COLDFIRE2M [MOTOROLA]
Microprocessor;
| 型号： | COLDFIRE2M |
| 厂家： | 
MOTOROLA |
| 描述： | Microprocessor |
| 文件： | 总253页 (文件大小：1233K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
ColdFire 2/2M
Integrated Microprocessor
User’s Manual
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MOTOROLA
ColdFire2/2M User’s Manual
iii
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iv
ColdFire2/2M User’s Manual
MOTOROLA
PREFACE
The ColdFire2/2M Integrated Microprocessor User’s Manual describes the programming,
capabilities, and operation of the ColdFire2/2M device. Refer to the MCF5200 ColdFire
Family Programmer’s Reference Manual Rev. 1.0 for information on the ColdFire Family of
microprocessors.
Throughout this document, the ColdFire2/2M integrated microprocessor is referred to as
“the ColdFire2/2M.”
CONTENTS
This user manual is organized as follows:
Section 1: Overview
Section 2: Signal Summary
Section 3: Master Bus Operations
Section 4: Exception Processing
Section 5: Integrated Memories
Section 6: Multiply-Accumulate Unit
Section 7: Debug Support
Section 8: Test Operation
Section 9: Instruction Execution Timing
Section 10: Electrical Characteristics
Appendix A: Register Summary
Appendix B: New MAC Instructions
Index
MOTOROLA
ColdFire2/2M User’s Manual
v
TABLE OF CONTENTS
Paragraph
Number
Page
Number
Title
Section 1
Overview
1.1
1.1.1
1.1.2
1.2
1.3
1.3.1
FlexCore Integrated Processors..................................................................1-2
FlexCore Advantages.............................................................................1-4
FlexCore Module Types .........................................................................1-4
Development Cycle......................................................................................1-5
System Architecture.....................................................................................1-8
Internal Bus Structure.............................................................................1-8
Master Bus.........................................................................................1-8
Slave Bus...........................................................................................1-9
External Bus ......................................................................................1-9
Test Bus.............................................................................................1-9
System Functional Blocks ......................................................................1-9
Alternate Master ................................................................................1-9
ColdFire2/2M .....................................................................................1-9
I-Cache Data Array..........................................................................1-10
I-Cache Tag Array ...........................................................................1-10
Master Bus Arbiter (MARB) .............................................................1-10
ROM Array.......................................................................................1-11
Slave Modules .................................................................................1-11
SRAM Array.....................................................................................1-11
System Bus Controller (SBC) ..........................................................1-11
Programming Model ..................................................................................1-11
Integer Unit User Programming Model.................................................1-11
Data Registers (D0 – D7) ................................................................1-12
Address Registers (A0 – A6) ...........................................................1-12
Stack Pointer (A7,SP)......................................................................1-12
Program Counter (PC).....................................................................1-12
Condition Code Register (CCR) ......................................................1-12
MAC Unit User Programming Model ....................................................1-13
Accumulator (ACC)..........................................................................1-14
Mask Register (MASK) ....................................................................1-14
MAC Status Register (MACSR).......................................................1-14
Supervisor Programming Model...........................................................1-14
1.3.1.1
1.3.1.2
1.3.1.3
1.3.1.4
1.3.2
1.3.2.1
1.3.2.2
1.3.2.3
1.3.2.4
1.3.2.5
1.3.2.6
1.3.2.7
1.3.2.8
1.3.2.9
1.4
1.4.1
1.4.1.1
1.4.1.2
1.4.1.3
1.4.1.4
1.4.1.5
1.4.2
1.4.2.1
1.4.2.2
1.4.2.3
1.4.3
MOTOROLA
ColdFire2/2M User’s Manual
vii
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
1.4.3.1
1.4.3.2
1.4.3.3
1.4.3.4
1.4.3.5
1.4.3.6
1.5
Status Register (SR)........................................................................1-14
Cache Control Register (CACR)......................................................1-15
Access Control Registers (ACR0, ACR1)........................................1-15
Vector Base Register (VBR)............................................................1-15
ROM Base Address Register (ROMBAR0) .....................................1-15
SRAM Base Address Register (RAMBAR0)....................................1-15
Integer Data Formats.................................................................................1-16
Organization of Data in Registers..............................................................1-16
Organization of Integer Data Formats in Registers..............................1-16
Organization of Integer Data Formats in Memory ................................1-17
Addressing Mode Summary ......................................................................1-18
Instruction Set Summary ...........................................................................1-19
1.6
1.6.1
1.6.2
1.7
1.8
Section 2
Signal Summary
2.1
2.2
Introduction..................................................................................................2-1
Master Bus Signals......................................................................................2-3
68K Interrupt Acknowledge Mode Enable (IACK_68K)..........................2-3
Master Address Bus (MADDR[31:0]) .....................................................2-3
Master Arbiter Control (MARBC[1:0]).....................................................2-3
Master Freeze (MFRZB) ........................................................................2-4
Master Kill (MKILLB) ..............................................................................2-4
Master Read Data Bus (MRDATA[31:0]) ...............................................2-4
Master Read Data Input Enable (MIE) ...................................................2-4
Master Read/Write (MRWB)...................................................................2-4
Master Reset (MRSTB)..........................................................................2-4
Master Size (MSIZ[1:0]) .........................................................................2-4
Master Transfer Acknowledge (MTAB) ..................................................2-5
Master Transfer Error Acknowledge (MTEAB).......................................2-5
Master Transfer Modifier (MTM[2:0])......................................................2-5
Master Transfer Start (MTSB)................................................................2-6
Master Transfer Type (MTT[1:0]) ...........................................................2-6
Master Write Data Bus (MWDATA[31:0])...............................................2-6
Master Write Data Output Enable (MWDATAOE)..................................2-6
General Control Signals ..............................................................................2-6
Clock (CLK)............................................................................................2-6
Interrupt Priority Level (IPLB[2:0])..........................................................2-6
Integrated Memory Signals..........................................................................2-7
Instruction Cache Signals.......................................................................2-7
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
2.2.9
2.2.10
2.2.11
2.2.12
2.2.13
2.2.14
2.2.15
2.2.16
2.2.17
2.3
2.3.1
2.3.2
2.4
2.4.1
viii
ColdFire2/2M User’s Manual
MOTOROLA
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
2.4.1.1
2.4.1.2
2.4.1.3
2.4.1.4
2.4.1.5
2.4.1.6
2.4.1.7
2.4.1.8
2.4.1.9
2.4.1.10
2.4.1.11
2.4.1.12
2.4.2
2.4.2.1
2.4.2.2
2.4.2.3
2.4.2.4
2.4.2.5
2.4.3
Instruction Cache Address Bus (ICH_ADDR[14:2])...........................2-7
Instruction Cache Data Chip-Select (ICHD_CSB).............................2-7
Instruction Cache Data Input Bus (ICHD_DI[31:0]) ...........................2-7
Instruction Cache Data Output Bus (ICHD_DO[31:0]).......................2-7
Instruction Cache Data Strobe (ICHD_ST)........................................2-7
Instruction Cache Data Read/Write (ICHD_RWB).............................2-7
Instruction Cache Size (ICH_SZ[2:0])................................................2-8
Instruction Cache Tag Chip-Select (ICHT_CSB)...............................2-8
Instruction Cache Tag Input Bus (ICHT_DI[31:8]).............................2-8
Instruction Cache Tag Output Bus (ICHT_DO[31:8]) ........................2-8
Instruction Cache Tag Strobe (ICHT_ST)..........................................2-9
Instruction Cache Tag Read/Write (ICHT_RWB) ..............................2-9
Integrated ROM Signals .........................................................................2-9
ROM Address Bus (ROM_ADDR[14:2])............................................2-9
ROM Data Output Bus (ROM_DO[31:0])...........................................2-9
ROM Enable (ROM_ENB[1:0])..........................................................2-9
ROM Size (ROM_SZ[2:0]).................................................................2-9
ROM Valid (ROM_VLD)...................................................................2-10
Integrated SRAM Signals .....................................................................2-10
SRAM Address Bus (SRAM_ADDR[14:2])......................................2-10
SRAM Chip-Select (SRAM_CSB)....................................................2-10
SRAM Data Input Bus (SRAM_DI[31:0]) .........................................2-11
SRAM Data Output Bus (SRAM_DO[31:0]).....................................2-11
SRAM Size (SRAM_SZ[2:0])...........................................................2-11
SRAM Strobe (SRAM_ST[3:0]) .......................................................2-11
SRAM Read/Write (SRAM_RWB[3:0]) ............................................2-11
2.4.3.1
2.4.3.2
2.4.3.3
2.4.3.4
2.4.3.5
2.4.3.6
2.4.3.7
2.5
Debug Signals ...........................................................................................2-11
Break Point (BKPTB)............................................................................2-11
Debug Data (DDATA[3:0])....................................................................2-12
Development Serial Clock (DSCLK).....................................................2-12
Development Serial Input (DSI)............................................................2-12
Development Serial Output (DSO) .......................................................2-12
Processor Status (PST[3:0]).................................................................2-12
Test Signals...............................................................................................2-12
Integrated Memory Test Signals...........................................................2-12
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
2.6
2.6.1
MOTOROLA
ColdFire2/2M User’s Manual
ix
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
2.6.1.1
2.6.1.2
2.6.1.3
2.6.1.4
2.6.1.5
2.6.1.6
2.6.1.7
2.6.1.8
2.6.1.9
2.6.1.10
2.6.1.11
2.6.1.12
2.6.1.13
2.6.1.14
2.6.2
2.6.2.1
2.6.2.2
2.6.2.3
2.6.2.4
2.6.2.5
2.6.2.6
2.6.2.7
2.6.2.8
2.6.2.9
2.6.2.10
2.6.2.11
2.6.2.12
2.6.2.13
Test Address Bus (TEST_ADDR[14:2]) ..........................................2-13
Test Control (TEST_CTRL).............................................................2-13
Test IDATA Read (TEST_IDATA_RD)............................................2-13
Test IDATA Write (TEST_IDATA_WRT) .........................................2-13
Test Instruction Cache Read Hit (TEST_RHIT)...............................2-13
Test Invalidate Inhibit (TEST_IVLD_INH)........................................2-13
Test ITAG Write (TEST_ITAG_WRT)..............................................2-13
Test KTA Mode Enable (TEST_KTA)..............................................2-13
Test Mode Enable (TEST_MODE)..................................................2-13
Test SRAM Read (TEST_SRAM_RD) ............................................2-13
Test SRAM Write (TEST_SRAM_WRT)..........................................2-13
Test Read (TEST_RD) ....................................................................2-13
Test ROM Read (TEST_ROM_RD) ................................................2-13
Test Write Inhibit (TEST_WR_INH).................................................2-13
Scan Signal Description .......................................................................2-13
Scan Enable (SCAN_ENABLE).......................................................2-14
Scan Exercise Array (SCAN_XARRAY)..........................................2-14
Scan Input (SCAN_IN[15:0]) ...........................................................2-14
Scan Mode (SCAN_MODE) ............................................................2-14
Scan Output (SCAN_OUT[15:0]).....................................................2-14
Scan Test Ring Clock (TR_CLK).....................................................2-14
Scan Test Ring Core Mode Enable (TR_CORE_EN) .....................2-14
Scan Test Ring Data Input 0 (TR_DI0)............................................2-14
Scan Test Ring Data Input 1 (TR_DI1)............................................2-14
Scan Test Ring Data Output 0 (TR_DO0).......................................2-14
Scan Test Ring Data Output 1 (TR_DO1).......................................2-14
Scan Test Ring Enable (TR_EN).....................................................2-14
Scan Test Ring Mode (TR_MODE).................................................2-14
Section 3
Master Bus Operation
3.1
Signal Description........................................................................................3-1
68K Interrupt Acknowledge Mode Enable (IACK_68K)..........................3-1
Master Address Bus (MADDR[31:0]) .....................................................3-1
Master Arbiter Control (MARBC[1:0]).....................................................3-1
Master Freeze (MFRZB) ........................................................................3-2
Master Kill (MKILLB) ..............................................................................3-2
Master Read Data Bus (MRDATA[31:0]) ...............................................3-2
Master Read Data Input Enable (MIE) ...................................................3-2
Master Read/Write (MRWB)...................................................................3-2
Master Reset (MRSTB)..........................................................................3-2
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.1.8
3.1.9
x
ColdFire2/2M User’s Manual
MOTOROLA
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
3.1.10
3.1.11
3.1.12
3.1.13
3.1.14
3.1.15
3.1.16
3.1.17
Master Size (MSIZ[1:0])..........................................................................3-2
Master Transfer Acknowledge (MTAB) ..................................................3-2
Master Transfer Error Acknowledge (MTEAB).......................................3-3
Master Transfer Modifier (MTM[2:0])......................................................3-3
Master Transfer Start (MTSB) ................................................................3-3
Master Transfer Type (MTT[1:0]) ...........................................................3-3
Master Write Data Bus (MWDATA[31:0])...............................................3-4
Master Write Data Output Enable (MWDATAOE)..................................3-4
3.2
Data Transfer Mechanism ...........................................................................3-4
Transfer Type Control Signals................................................................3-4
ColdFire2/2M Access.........................................................................3-4
Alternate Master Access....................................................................3-5
Emulator Mode Access......................................................................3-5
Interrupt Acknowledge Access ..........................................................3-5
CPU Space Access ...........................................................................3-5
Data Bus Requirements .........................................................................3-5
Data Transfers.............................................................................................3-6
Byte, Word, and Longword Read Transfers ...........................................3-6
Byte, Word, and Longword Write Transfers ...........................................3-9
Line Read Transfer...............................................................................3-11
Line Write Transfers .............................................................................3-14
Misaligned Operands.................................................................................3-18
Invalid Master Bus Cycles .........................................................................3-20
Pipeline Stalls ............................................................................................3-20
Interrupt Acknowledge Bus Cycles............................................................3-21
Interrupt Acknowledge Bus Cycle (Terminated normally) ....................3-22
Spurious Interrupt Acknowledge Bus Cycle .........................................3-27
Master Bus Exception Control Cycles .......................................................3-27
Bus Errors.............................................................................................3-28
Fault-on-Fault Halt................................................................................3-29
Reset Operation.........................................................................................3-29
Master Bus Arbitration ...............................................................................3-30
Master Bus Arbitration Algorithm..........................................................3-30
Park on ColdFire2/2M......................................................................3-30
Park on Alternate Master.................................................................3-30
Park on Current Master ...................................................................3-31
Bus Arbitration Programming Model.....................................................3-31
3.2.1
3.2.1.1
3.2.1.2
3.2.1.3
3.2.1.4
3.2.1.5
3.2.2
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.4
3.5
3.6
3.7
3.7.1
3.7.2
3.8
3.8.1
3.8.2
3.9
3.10
3.10.1
3.10.1.1
3.10.1.2
3.10.1.3
3.10.2
Section 4
Exception Processing
4.1
Exception Processing Overview ..................................................................4-1
MOTOROLA
ColdFire2/2M User’s Manual
xi
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
4.1.1
4.1.1.1
4.1.2
4.1.3
4.1.4
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
4.2.10
4.2.11
4.2.11.1
4.2.11.2
Exception Stack Frame Definition ..........................................................4-3
Self-Aligning Stack ............................................................................4-4
Exception Vectors ..................................................................................4-5
Multiple Exceptions ................................................................................4-6
Fault-on-Fault Halt..................................................................................4-6
Exceptions...................................................................................................4-7
Reset Exception .....................................................................................4-7
Access Error Exception..........................................................................4-7
Address Error Exception ........................................................................4-8
Illegal Instruction Exception....................................................................4-9
Privilege Violation Exception..................................................................4-9
Trace Exception .....................................................................................4-9
Unimplemented Opcode Exception........................................................4-9
Debug Interrupt ....................................................................................4-10
Format Error Exceptions ......................................................................4-10
TRAP Instruction Exceptions................................................................4-10
Interrupt Exception ...............................................................................4-10
Level Seven Interrupts.....................................................................4-11
Spurious, Autovectored, and Uninitialized Interrupts.......................4-12
Section 5
Integrated Memories
5.1
5.1.1
Instruction Cache.........................................................................................5-1
Instruction Cache Signal Description .....................................................5-1
Instruction Cache Address Bus (ICH_ADDR[14:2]) ..........................5-2
Instruction Cache Data Chip-Select (ICHD_CSB).............................5-2
Instruction Cache Data Input Bus (ICHD_DI[31:0])...........................5-2
Instruction Cache Data Output Bus (ICHD_DO[31:0]) ......................5-2
Instruction Cache Data Strobe (ICHD_ST)........................................5-2
Instruction Cache Data Read/Write (ICHD_RWB) ............................5-3
Instruction Cache Size (ICH_SZ[2:0]) ...............................................5-3
Instruction Cache Tag Chip-Select (ICHT_CSB)...............................5-3
Instruction Cache Tag Input Bus (ICHT_DI[31:8]).............................5-3
Instruction Cache Tag Output Bus (ICHT_DO[31:8]) ........................5-3
Instruction Cache Tag Strobe (ICHT_ST) .........................................5-4
Instruction Cache Tag Read/Write (ICHT_RWB) ..............................5-4
Instruction Cache Physical Organization................................................5-4
Interaction With Other Modules..............................................................5-4
Cache Miss Fetch Algorithm/Line Fills ...................................................5-4
Cacheability............................................................................................5-5
Invalidating Cache Entries......................................................................5-5
5.1.1.1
5.1.1.2
5.1.1.3
5.1.1.4
5.1.1.5
5.1.1.6
5.1.1.7
5.1.1.8
5.1.1.9
5.1.1.10
5.1.1.11
5.1.1.12
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
5.1.7
5.1.8
5.1.9
Cache Coherency...................................................................................5-6
Reset ......................................................................................................5-6
Instruction Cache Programming Model ..................................................5-6
5.2
5.2.1
5.3
5.3.1
5.3.1.1
5.3.1.2
5.3.1.3
5.3.1.4
5.3.1.5
5.3.2
Access Control Registers ............................................................................5-8
ACR Programming Model.......................................................................5-8
ROM Module..............................................................................................5-10
ROM Signal Description .......................................................................5-10
ROM Address Bus (ROM_ADDR[14:2])..........................................5-11
ROM Data Output Bus (ROM_DO[31:0]).........................................5-11
ROM Enable (ROM_ENB[1:0])........................................................5-11
ROM Size (ROM_SZ[2:0])...............................................................5-12
ROM Valid (ROM_VLD)...................................................................5-12
ROM Programming Model....................................................................5-12
SRAM Module............................................................................................5-14
SRAM Signal Description .....................................................................5-14
SRAM Address Bus (SRAM_ADDR[14:2])......................................5-15
SRAM Chip-Select (SRAM_CSB)....................................................5-16
SRAM Data Input Bus (SRAM_DI[31:0]) .........................................5-16
SRAM Data Output Bus (SRAM_DO[31:0]).....................................5-16
SRAM Size (SRAM_SZ[2:0])...........................................................5-16
SRAM Strobe (SRAM_ST[3:0]) .......................................................5-16
SRAM Read/Write (SRAM_RWB[3:0]) ............................................5-16
SRAM Programming Model..................................................................5-16
5.4
5.4.1
5.4.1.1
5.4.1.2
5.4.1.3
5.4.1.4
5.4.1.5
5.4.1.6
5.4.1.7
5.4.2
Section 6
Multiply-Accumulate Unit
6.1
6.2
6.2.1
6.2.2
6.2.3
6.3
Introduction..................................................................................................6-1
MAC Programming Model ...........................................................................6-2
Accumulator (ACC).................................................................................6-2
MAC Status Register (MACSR)..............................................................6-2
Mask Register (MASK)...........................................................................6-3
Shifting Operations ......................................................................................6-4
Overflow Mode.............................................................................................6-4
MAC Instruction Set Summary ....................................................................6-5
6.4
6.5
Section 7
Debug Support
7.1
7.1.1
7.1.2
Signal Description........................................................................................7-1
Break Point (BKPTB)..............................................................................7-1
Debug Data (DDATA[3:0])......................................................................7-2
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
7.1.3
7.1.4
7.1.5
7.1.6
7.2
7.2.1
Development Serial Clock (DSCLK).......................................................7-2
Development Serial Input (DSI)..............................................................7-2
Development Serial Output (DSO).........................................................7-2
Processor Status (PST[3:0])...................................................................7-2
Real-Time Trace..........................................................................................7-2
Processor Status Signal Encoding.........................................................7-3
Continue Execution (PST = $0).........................................................7-3
Begin Execution of an Instruction (PST = $1)....................................7-3
Entry into User Mode (PST = $3) ......................................................7-3
Begin Execution of PULSE or WDDATA instructions (PST = $4) .....7-3
Begin Execution of Taken Branch (PST = $5)...................................7-4
Begin Execution of RTE Instruction (PST = $7) ................................7-5
Begin Data Transfer (PST = $8 - $A) ................................................7-5
Exception Processing (PST = $C).....................................................7-5
Emulator-Mode Exception Processing (PST = $D) ...........................7-5
Processor Stopped (PST = $E) .........................................................7-5
Processor Halted (PST = $F) ............................................................7-5
Background Debug Mode (BDM) ................................................................7-5
CPU Halt ................................................................................................7-6
BDM Serial Interface ..............................................................................7-7
Receive Packet Format .....................................................................7-8
Transmit Packet Format ....................................................................7-9
BDM Command Set ...............................................................................7-9
BDM Command Set Summary ..........................................................7-9
ColdFire BDM Commands...............................................................7-10
Command Sequence Diagram ........................................................7-11
Command Set Descriptions.............................................................7-12
Read A/D Register (RAREG/RDREG).......................................7-13
Write A/D Register (WAREG/WDREG)......................................7-13
Read Memory Location (READ).................................................7-14
Write Memory Location (WRITE) ...............................................7-16
Dump Memory Block (DUMP)....................................................7-17
Fill Memory Block (FILL) ............................................................7-19
Resume Execution (GO)............................................................7-21
No Operation (NOP)...................................................................7-21
Read Control Register (RCREG) ...............................................7-22
Write Control Register (WCREG)...............................................7-23
Read Debug Module Register (RDMREG) ................................7-24
Write Debug Module Register (WDMREG)................................7-25
Unassigned Opcodes.................................................................7-25
Real-Time Debug Support.........................................................................7-26
Theory of Operation .............................................................................7-26
7.2.1.1
7.2.1.2
7.2.1.3
7.2.1.4
7.2.1.5
7.2.1.6
7.2.1.7
7.2.1.8
7.2.1.9
7.2.1.10
7.2.1.11
7.3
7.3.1
7.3.2
7.3.2.1
7.3.2.2
7.3.3
7.3.3.1
7.3.3.2
7.3.3.3
7.3.3.4
7.3.3.4.1
7.3.3.4.2
7.3.3.4.3
7.3.3.4.4
7.3.3.4.5
7.3.3.4.6
7.3.3.4.7
7.3.3.4.8
7.3.3.4.9
7.3.3.4.10
7.3.3.4.11
7.3.3.4.12
7.3.3.4.13
7.4
7.4.1
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
7.4.1.1
7.4.1.2
7.4.2
7.4.2.1
7.4.2.2
7.4.2.3
7.4.2.4
7.4.2.5
7.4.2.6
7.4.3
Emulator Mode ................................................................................7-27
Reuse of Debug Module Hardware .................................................7-28
Programming Model .............................................................................7-28
Address Breakpoint Registers (ABLR, ABHR) ................................7-29
Address Attribute Register (AATR)..................................................7-30
Program Counter Breakpoint Register (PBR, PBMR) .....................7-32
Data Breakpoint Register (DBR, DBMR).........................................7-33
Trigger Definition Register (TDR) ....................................................7-34
Configuration/Status Register (CSR)...............................................7-36
Concurrent BDM and Processor Operation..........................................7-39
Motorola Recommended BDM Pinout..................................................7-39
Differences Between the ColdFire2/2M BDM and CPU32 BDM ..........7-40
7.4.4
7.4.5
Section 8
Test Operation
8.1
8.1.1
Integrated Memory Testing..........................................................................8-1
Test Bus Signal Description ...................................................................8-1
Test Address Bus (TEST_ADDR[14:2]).............................................8-1
Test Control (TEST_CTRL) ...............................................................8-1
Test IDATA Read (TEST_IDATA_RD) ..............................................8-1
Test IDATA Write (TEST_IDATA_WRT) ...........................................8-2
Test Instruction Cache Read Hit (TEST_RHIT).................................8-2
Test Invalidate Inhibit (TEST_IVLD_INH)..........................................8-2
Test ITAG Write (TEST_ITAG_WRT)................................................8-2
Test KTA Mode Enable (TEST_KTA)................................................8-2
Test Mode Enable (TEST_MODE) ....................................................8-2
Test SRAM Read (TEST_SRAM_RD)...............................................8-2
Test SRAM Write (TEST_SRAM_WRT)............................................8-2
Test Read (TEST_RD) ......................................................................8-2
Test ROM Read (TEST_ROM_RD)...................................................8-2
Test Write Inhibit (TEST_WR_INH)...................................................8-2
Theory of Operation................................................................................8-2
Test Mode...............................................................................................8-3
Instruction Cache Tag RAM Testing.......................................................8-3
Instruction Cache Tag RAM Write Function ......................................8-3
Instruction Cache Tag RAM Read Function ......................................8-5
Instruction Cache Data RAM Testing .....................................................8-6
Instruction Cache Data RAM Write Function.....................................8-6
Instruction Cache Data RAM Read Function.....................................8-8
Instruction Cache KTA Mode Testing.....................................................8-9
ROM Testing ........................................................................................8-11
8.1.1.1
8.1.1.2
8.1.1.3
8.1.1.4
8.1.1.5
8.1.1.6
8.1.1.7
8.1.1.8
8.1.1.9
8.1.1.10
8.1.1.11
8.1.1.12
8.1.1.13
8.1.1.14
8.1.2
8.1.3
8.1.4
8.1.4.1
8.1.4.2
8.1.5
8.1.5.1
8.1.5.2
8.1.6
8.1.7
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
8.1.7.1
8.1.8
8.1.8.1
8.1.8.2
8.2
ROM Read Function........................................................................8-11
SRAM Testing ......................................................................................8-13
SRAM Write Function......................................................................8-13
SRAM Read Function......................................................................8-15
Scan Testing..............................................................................................8-16
Scan Signal Description .......................................................................8-16
Scan Enable (SCAN_ENABLE).......................................................8-16
Scan Exercise Array (SCAN_XARRAY)..........................................8-16
Scan Input (SCAN_IN[15:0]) ...........................................................8-16
Scan Mode (SCAN_MODE) ............................................................8-17
Scan Output (SCAN_OUT[15:0]).....................................................8-17
Scan Test Ring Clock (TR_CLK).....................................................8-17
Scan Test Ring Core Mode Enable (TR_CORE_EN) .....................8-17
Scan Test Ring Data Input 0 (TR_DI0)............................................8-17
Scan Test Ring Data Input 1 (TR_DI1)............................................8-17
Scan Test Ring Data Output 0 (TR_DO0).......................................8-17
Scan Test Ring Data Output 1 (TR_DO1).......................................8-17
Scan Test Ring Enable (TR_EN).....................................................8-17
Scan Test Ring Mode (TR_MODE).................................................8-17
Test Ring..............................................................................................8-17
Burn-In Testing..........................................................................................8-18
Data Retention Testing..............................................................................8-18
8.2.1
8.2.1.1
8.2.1.2
8.2.1.3
8.2.1.4
8.2.1.5
8.2.1.6
8.2.1.7
8.2.1.8
8.2.1.9
8.2.1.10
8.2.1.11
8.2.1.12
8.2.1.13
8.2.2
8.3
8.4
Section 9
Instruction Execution Timing
9.1
9.2
9.3
9.4
9.5
9.6
9.7
Timing Assumptions ....................................................................................9-1
MOVE Instruction Execution Times.............................................................9-2
Standard One-Operand Instruction Execution Times..................................9-4
Standard Two-Operand Instruction Execution Times..................................9-5
Miscellaneous Instruction Execution Times.................................................9-7
MAC Instruction Execution Timing ..............................................................9-8
Branch Instruction Execution Times............................................................9-8
Section 10
Electrical Chacteristics
10.1
Definitions of Specifications.......................................................................10-1
Current .................................................................................................10-1
Voltage .................................................................................................10-1
Capacitance .........................................................................................10-2
AC Switching Parameters and Waveforms ..........................................10-2
10.1.1
10.1.2
10.1.3
10.1.4
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
10.2
ColdFire2 Data Sheet ................................................................................10-6
Appendix A
Register Summary
A.1
A.2
Register Access Methods........................................................................... A-1
Register Formats ........................................................................................ A-2
Appendix B
New MAC Instructions
B.1
B.2
B.3
B.4
Enhanced Integer Multiply Instructions....................................................... B-1
New MAC Instructions ................................................................................ B-1
New Register Instructions......................................................................... B-12
Operation Code Map ................................................................................ B-22
MOTOROLA
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xvii
LIST OF ILLUSTRATIONS
Figure
Page
Number
Title
Number
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
FlexCore Integrated Processor Typical Die Layout...........................................1-3
Design System Overview..................................................................................1-7
ColdFire2/2M System Diagram.........................................................................1-8
ColdFire2/2M Block Diagram ..........................................................................1-10
Integer Unit User Programming Model............................................................1-12
Condition Code Register (CCR)......................................................................1-13
MAC Unit User Programming Model...............................................................1-13
Supervisor Programming Model......................................................................1-14
Status Register (SR) .......................................................................................1-15
1-10 Organization of Integer Data Formats in Data Registers ................................1-16
1-11 Organization of Integer Data Formats in Address Registers...........................1-17
1-12 Memory Operand Addressing .........................................................................1-18
2-1
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
ColdFire2/2M Detailed Block Diagram..............................................................2-1
Byte, Word, and Longword Read Transfer Flowchart.......................................3-7
Normal Transfer (without Wait States)..............................................................3-8
Byte, Word, and Longword Write Transfer Flowchart .......................................3-9
Normal Write Transfer (with wait states).........................................................3-10
Line Read Transfer Flowchart.........................................................................3-12
Line Read Transfer (without wait states).........................................................3-13
Line Write Transfer Flowchart.........................................................................3-15
Line Write Transfer (without wait states).........................................................3-16
Line Write Transfer (with wait states)..............................................................3-17
3-10 Example of a Misaligned Longword Transfer ................................................3-18
3-11 Example of a Misaligned Word Transfer.........................................................3-18
3-12 Misaligned Word Read Transfer .....................................................................3-19
3-13 Example Master Bus Wait State .....................................................................3-21
3-14 Interrupt Acknowledge Bus Cycle Flowchart...................................................3-23
3-15 ColdFire Mode Interrupt Acknowledge Bus Cycle...........................................3-24
3-16 68K Mode Interrupt Acknowledge Bus Cycle..................................................3-26
3-17 Bus Exception Cycle .......................................................................................3-29
3-18 Initial Power-On Reset ....................................................................................3-30
4-1
4-2
5-1
5-2
5-3
5-4
5-5
Exception Processing Flowchart.......................................................................4-2
Exception Stack Frame Form............................................................................4-3
Example 8 Kbyte Instruction Cache Interface Diagram ....................................5-2
Cache Control Register (CACR) .......................................................................5-6
Access Control Register (ACR0, ACR1)...........................................................5-9
Example 8 Kbyte ROM Interface Diagram......................................................5-11
ROM Base Address Register (ROMBAR0).....................................................5-12
MOTOROLA
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xix
LIST OF ILLUSTRATIONS (Continued)
Figure
Page
Number
Title
Number
5-6
5-7
6-1
6-2
6-3
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
Example 8 Kbyte SRAM Interface Diagram....................................................5-15
SRAM Base Address Register (RAMBAR0)...................................................5-17
MAC Flow Diagram...........................................................................................6-2
MAC Status Register (MACSR)........................................................................6-3
MAC Mask Register (MASK) ............................................................................6-4
Processor/Debug Module Interface ..................................................................7-1
Example PST Diagram .....................................................................................7-4
BDM Serial Transfer .........................................................................................7-8
BDM Signal Sampling.......................................................................................7-8
Receive BDM Packet........................................................................................7-8
Transmit BDM Packet.......................................................................................7-9
Command Sequence Diagram........................................................................7-12
Debug Programming Model............................................................................7-29
Address Breakpoint Low Register (ABLR)......................................................7-29
7-10 Address Breakpoint High Register (ABHR) ....................................................7-30
7-11 Address Attribute Register (AATR).................................................................7-30
7-12 Program Counter Breakpoint Register (PBR).................................................7-32
7-13 Program Counter Breakpoint Mask Register (PBMR) ....................................7-33
7-14 Data Breakpoint Register (DBR).....................................................................7-33
7-15 Data Breakpoint Mask Register (DBMR) ........................................................7-33
7-16 Trigger Definition Register (TDR) ...................................................................7-34
7-17 Configuration/Status Register (CSR)..............................................................7-37
7-18 Recommended BDM Connector.....................................................................7-40
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
10-1
Test Instruction Cache Tag Write Cycles..........................................................8-4
Test Instruction Cache Tag Read Cycles .........................................................8-5
Test Instruction Cache Data Write Cycles ........................................................8-7
Test Instruction Cache Data Read Cycles........................................................8-8
KTA Mode Cycles ...........................................................................................8-10
Test ROM Read Cycles ..................................................................................8-12
Test SRAM Write Cycles ................................................................................8-14
Test SRAM Read Cycles ................................................................................8-15
t
and t
Measurements..........................................................................10-2
PLH
PHL
10-2 t and t Measurements ...................................................................................10-2
r
f
10-3 Internal Cell Three-State Measurements and Example Circuits.....................10-3
10-4 Recovery Time..........................................................................................10-4
10-5 t and t Measurements Between Data and a Control Signal .......................10-4
t
rec
su
h
10-6 t and t Measurements Between Data and Clock Signals...........................10-4
su
h
10-7 Switching Waveforms Showing t
and t
Measurements.......................10-5
w(L)
w(H)
A-1
A-2
A-3
A-4
Address Attribute Register (AATR)...................................................................A-2
Address Breakpoint High Register (ABHR) ......................................................A-2
Address Breakpoint Low Register (ABLR)........................................................A-2
Access Control Register (ACR0, ACR1)...........................................................A-3
xx
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MOTOROLA
LIST OF ILLUSTRATIONS (Continued)
Figure
Page
Number
Title
Number
A-5
A-6
A-7
1-8
1-9
Cache Control Register (CACR) ...................................................................... A-3
Condition Code Register (CCR)....................................................................... A-3
Configuration/Status Register (CSR) ............................................................... A-4
Data Breakpoint Mask Register (DBMR) ......................................................... A-4
Data Breakpoint Register (DBR)...................................................................... A-4
1-10 MAC Status Register (MACSR) ....................................................................... A-4
1-11 MAC Mask Register (MASK)............................................................................ A-5
1-12 Program Counter Breakpoint Mask Register (PBMR)...................................... A-5
1-13 Program Counter Breakpoint Register (PBR) .................................................. A-5
A-14 SRAM Base Address Register (RAMBAR0) .................................................... A-5
A-15 ROM Base Address Register (ROMBAR0)...................................................... A-6
A-16 Status Register (SR) ........................................................................................ A-6
A-17 Trigger Definition Register (TDR)..................................................................... A-6
MOTOROLA
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LIST OF TABLES
Table
Page
Number
Title
Number
1-1
1-2
1-3
1-4
1-5
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
MOVEC Register Map.....................................................................................1-14
Integer Data Formats ......................................................................................1-16
Effective Addressing Modes and Categories..................................................1-19
Notational Conventions...................................................................................1-19
Instruction Set Summary.................................................................................1-21
Signal Summary................................................................................................2-2
Master Arbiter Control Encoding.......................................................................2-4
Master Bus Transfer Size Encoding..................................................................2-5
Master Bus Transfer Modifier Encoding............................................................2-5
Master Bus Transfer Type Encoding.................................................................2-6
Interrupt Levels and Mask Values.....................................................................2-7
Cache Configuration Encoding .........................................................................2-8
Valid Tag RAM Data Signals.............................................................................2-8
Valid ROM Address Bits....................................................................................2-9
2-10 ROM Configuration Encoding .........................................................................2-10
2-11 Valid SRAM Address Bits................................................................................2-10
2-12 SRAM Configuration Encoding .......................................................................2-11
2-13 Processor Status Encoding.............................................................................2-12
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
4-1
4-2
4-3
4-4
5-1
5-2
5-3
5-4
5-5
5-6
5-7
Master Arbiter Control Encoding.......................................................................3-1
Master Bus Transfer Size Encoding..................................................................3-2
Master Bus Transfer Modifier Encoding............................................................3-3
Master Bus Transfer Type Encoding.................................................................3-4
MRDATA Requirements for Read Transfers.....................................................3-5
MWDATA Bus Requirements for Write Transfers.............................................3-6
Allowable Line Access Patterns......................................................................3-11
Memory Alignment Cycles ..............................................................................3-19
MTAB and MTEAB Assertion Results.............................................................3-27
Stack Pointer Alignment....................................................................................4-5
Exception Vector Assignments .........................................................................4-5
Exception Priority Groups .................................................................................4-6
Interrupt Levels and Mask Values...................................................................4-11
Cache Configuration Encoding .........................................................................5-3
Valid Tag RAM Data Signals.............................................................................5-3
Initial Fetch Offset and CLNF Bits.....................................................................5-5
Cache Line Fill Encoding ..................................................................................5-8
Valid ROM Address Bits..................................................................................5-11
ROM Configuration Encoding .........................................................................5-12
Valid ROM Base Address Bits ........................................................................5-13
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LIST OF TABLES (Continued)
Figure
Page
Number
Title
Number
5-8
5-9
Valid SRAM Address Bits ...............................................................................5-15
SRAM Configuration Encoding.......................................................................5-16
5-10 Valid SRAM Base Address Bits ......................................................................5-17
6-1
6-2
6-3
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
Mask Addressing Mode ....................................................................................6-4
Accumulator Result in Saturation Mode............................................................6-5
MAC Instruction Set Summary..........................................................................6-6
Processor Status Encoding ..............................................................................7-2
CPU-Generated Message Encoding ................................................................7-9
BDM Command Summary..............................................................................7-10
BDM Size Field Encoding ...............................................................................7-11
Control Register Map......................................................................................7-22
Definition of DRc Encoding - Read .................................................................7-24
Definition of DRc Encoding - Write .................................................................7-25
DDATA, CSR[31:28] Breakpoint Response....................................................7-26
Shared BDM/Breakpoint Hardware.................................................................7-28
7-10 Misaligned Data Operand References............................................................7-34
7-11 BDM Connector Correlation............................................................................7-40
9-1
9-2
9-3
9-4
9-5
9-6
9-7
9-8
9-9
A-1
Misaligned Operand References ......................................................................9-2
Move Byte and Word Execution Times.............................................................9-3
Move Long Execution Times ............................................................................9-3
One Operand Instruction Execution Times.......................................................9-4
Two Operand Instruction Execution Times.......................................................9-5
Miscellaneous Instruction Execution Times......................................................9-7
MAC Instruction Execution Times.....................................................................9-8
General Branch Instruction Execution Times....................................................9-8
BRA, BCC Instruction Execution Times............................................................9-8
Register Summary ............................................................................................A-1
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LIST OF ACRONYMS
Acronym
Definition
BCD ........................................................binary coded decimal
BDM........................................................background debug mode
CAD ........................................................computer-aided design
CPU ........................................................central processing unit
DSP ........................................................digital signal processing
ET ...........................................................execution time
IACK .......................................................interrupt acknowledge
IFP ..........................................................instruction fetch pipeline
LRU.........................................................least recently used
LSB.........................................................least significant bit
LSW........................................................least significant word
MAC........................................................multiply-accumulate
MARB .....................................................master bus arbiter
MSB........................................................most significant bit
MSW.......................................................most significant word
OEP ........................................................operand execution pipeline
RISC .......................................................reduced instruction set computer
ROM .......................................................read-only memory
SBC ........................................................system bus controller
SRAM .....................................................static random access memory
TA ...........................................................transfer acknowledge
TS ...........................................................transfer start
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SECTION 1
OVERVIEW
This is a summary of the use and operation of the FlexCore ColdFire® microprocessor core
(referred to as the ColdFire2) and FlexCore ColdFire microprocessor core with the Multiply-
Accumulate unit (MAC), referred to as the ColdFire2M. It also contains a detailed set of
timing and electrical specifications. All references to ColdFire2/2M will apply to both the
ColdFire2 and the ColdFire2M devices. Refer to the ColdFire Programmer’s Reference
Manual Rev 1.0 (MCF5200PRM/AD) for detailed information on the operation of the
instruction set and addressing modes.
The ColdFire2/2M is part of the FlexCore Program, a semicustom, standard-cell based
design program. Based on the concept of variable-length Reduced Instruction Set Computer
(RISC) technology, ColdFire combines the architectural simplicity of conventional 32-bit
RISC with a memory-saving, variable-length instruction set. In the FlexCore program, high-
volume manufacturers can create their own integrated microprocessor containing a core
processor (such as the ColdFire2/2M) and their own proprietary technology. A FlexCore
integrated processor allows significant reductions in component count, power consumption,
board space, and cost—resulting in higher system reliability and performance.
The main features of the ColdFire2/2M processor include:
• 32-bit address bus which can directly address up to 4 Gbytes
• 32-bit data bus
• Variable-length RISC
• Optimized instruction set for high-level language constructs
• Sixteen general-purpose 32-bit data- and address- registers
• Multiply Accumulate (MAC) unit for DSP applications (ColdFire2M only)
• Supervisor/user modes for system protection
• Vector-base register to relocate exception-vector table
• Special core interfacing signals for integrated memories
• Full debug support
The ColdFire2/2M has 32-bit address and data busses. The 32-bit address bus allows direct
addressing of up to 4 Gbytes. A misalignment unit provides support for misaligned data
accesses, and an optional bus arbitration unit provides support for additional bus masters.
The ColdFire2/2M also supports an integrated instruction cache, SRAM, and ROM
(maximum of 32 Kbyte each.)
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The ColdFire2/2M supports a subset of the 68000 instruction set, and the ColdFire2M has
the added functionality of a Multiply Accumulate (MAC) unit for DSP applications. The
removed instructions include binary coded decimal, bit field, logical rotate, decrement and
branch, integer division, and integer multiply with a 64-bit result. In addition, only the twelve
addressing modes supported by the 68000 are supported. User-mode code developed for
the ColdFire2 processor will run unchanged on 68020, 68030, 68040, and 68060
processors. The new MAC instructions on the ColdFire2M processor will not run on other
processors.
A complete debug module is integrated into the ColdFire2/2M. This unit provides real-time
trace, background debug mode, and real-time debug support. This includes a parallel
processor status port, a subset of the background debug mode (BDM) functionality found on
Motorola’s 683xx family of parts, and real-time breakpoint capability. This built-in debug
support results in a standard debug interface to established tools for all ColdFire-based
processors.
1.1 FLEXCORE INTEGRATED PROCESSORS
The FlexCore design methodology allows designers of high-volume digital systems and
third-party technology providers to place their proprietary circuitry on-chip with a Motorola
microprocessor core. By using FlexCore, a designer can reduce the total system cost,
component count, and power consumption while providing higher performance and greater
reliability. Custom logic, memory, and peripheral modules can be added to a core processor
to produce the most cost-effective solution for a designer's system. Core processors provide
special power-management features such as 5 V, 3.3 V, and static operation. The 68000
family of processors have a proven architecture with a broad base of application and system
software support, including real-time kernels, operating systems, and compilers, in addition
to a wide range of tools to support software development. In the future, additional processing
architectures will be included in the FlexCore program, including PowerPC and Digital
Signal Processing (DSP). Figure 1-1 shows a typical die layout of a FlexCore integrated
processor.
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CUSTOMER-DESIGNED
LOGIC
SPECIAL-FUNCTION
OR MEMORY BLOCK
FLEXCORE FAMILY
PROCESSOR CORE
SPECIAL FUNCTION
OR MEMORY BLOCK
Figure 1-1. FlexCore Integrated Processor Typical Die Layout
Complete product lines can be created using FlexCore by implementing one base design
using a variety of core processors. Designers already familiar with 680x0 Family design can
easily migrate to FlexCore processors as the core processors use similar interfaces.
Additionally, many peripheral modules and memory elements are available for integration.
Motorola has developed a complete design system for the customer that includes both a
broad cell-based library and effective Computer-Aided Design (CAD) tools. By building on
Motorola's proven 680x0 microprocessor architecture and superior manufacturing
capabilities, FlexCore offers designers the best path to higher system integration.
FlexCore custom processors are ideal for:
• High-volume users of 8-, 16-, and 32-bit integrated solutions requiring higher system
performance whose needs are not met by standard 68300 Family devices.
• Designers of high-volume applications who need to reduce cost, space, and/or power
consumption.
• Third-party technology providers who want to deliver their proprietary application-
specific technology to a worldwide marketplace.
To develop a solution that best suits system requirements in the shortest time frame,
integrated processor design is performed by the designer using a methodology created,
tested, and documented by Motorola. The resulting netlist is then laid out by Motorola,
verified, and fabricated in silicon. This enables FlexCore integrated processors to be
produced quickly and cost-effectively, with the resulting device integrating many of the
discrete functions needed in the final system.
To implement the application-specific logic, the designer uses Motorola's standard-cell
library. This library offers an extensive range of design elements, memory configurations,
and an expanding array of peripheral modules. Each cell in the library has been designed
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for optimum size, power, and performance. The added flexibility of high-speed, high-density
cells allows the designer to achieve the most cost-effective solution while satisfying critical
timing requirements. The standard cell library has been thoroughly characterized and
maintained to ensure a smooth transition from a simulated design to working silicon. If both
Motorola and the customer have the desire, a custom part may also become a standard
product. Standard products are sold on the open market, allowing costs to be spread over
additional units, resulting in lower component prices for high-volume users.
Third-party technology providers can use the same methodology to combine their
application-specific systems expertise with a core processor. The resulting device is
manufactured by Motorola and can be delivered to the marketplace through either the
technologist’s or Motorola’s marketing and sales channels.
Refer to the Design System User’s Guide for Semicustom & FlexCore for more information
on the FlexCore design methodology.
1.1.1 FlexCore Advantages
Developers face challenges in reducing product cost. By incorporating user-designed logic
and Motorola-supplied functions into a single FlexCore processor, a system designer can
realize significant savings in cost, power consumption, board space, and pin count. The
equivalent functionality can easily require 20 separate components. Each component might
have 16–64 pins, totaling over 350 connections. Each connection is a candidate for a bad
solder joint or misrouted trace. Each component is another part to qualify, purchase,
inventory, and maintain. Each component requires a share of the printed circuit board. Each
component draws power—often to drive large buffers and circuit board traces to get signals
to another chip. Each component must be individually placed and attached to a printed
circuit board. The signals between the core processor unit and a peripheral might not be
compatible nor run from the same clock, requiring time delays or other special design
considerations.
In a FlexCore integrated processor, the major functions and glue logic are all properly
connected internally, timed with the same clock, and fully tested. Only essential signals are
brought out to pins. The processor is then assembled and tested in a surface-mount
package for the smallest possible footprint.
1.1.2 FlexCore Module Types
The three types of FlexCore modules are:
• Hard Module
— Not alterable
— Laid out
— Has a technology file containing timing data
— Has a defined test scheme
• Soft Module
— Netlist
— Not alterable other than by clock tree insertion
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— Not laid out
— Has a defined test scheme
— Simulation test fixture is provided
• Parameterizable Module
— Alterable via insertion of predefined parameters
— Behavioral model
— Definition of parameters defines test scheme
— Customer selects parameter values and Motorola synthesizes the design
The ColdFire2/2M is available as a hard module only.
1.2 DEVELOPMENT CYCLE
There are several steps that must be followed in order to create a FlexCore integrated mi-
croprocessor with a ColdFire2/2M. Figure 1-2 illustrates the standard cell design flow. These
steps include:
• Schematic capture on workstation—Use the engineering workstation to implement the
required system functions with a ColdFire2/2M, memory blocks, peripherals, and cells
from the Motorola standard cell library.
• Verilog modules—Optionally use Verilog to implement complex user modules or
system interconnect of standard cells.
• Generate test patterns—Generate the stimulus and test patterns for the design to be
used during functional simulation.
• Module compilation—Use Motorola software to generate compiled modules (SRAM,
ROM, etc.)
• Functional simulation—Ensure that the logic of the system is functionally sound by
simulating the design. (No timing information is yet associated with the simulations, and
all propagation delays are preset to a unit delay.)
• Logic synthesis—The behavioral and structural level description of the design is
mapped to a more efficient structural description using Synopsys. This final description
is a netlist of standard cell components.
• Electrical rule check—Motorola software verifies the electrical integrity of the design.
This includes checking connectivity, fan-out, edge rates, and other electrical rules.
• Calculate node delays— Motorola software calculates the estimated propagation
delays of each node in the circuit. The design software estimates delays based on the
fanout, input rise/fall times, drive characteristics, and estimated interconnect
capacitances of the netlist.
• Path delay analysis—With path delay information, the delays between the clocked
elements of the circuit can be determined, and the critical paths that limit the clock rate
can be identified. Checking for setup, hold, and pulse-width violations can also be
accomplished.
• Perform real-time simulation—The real-time simulation is run to verify full functionality
using the estimated propagation delays calculated by the design tools.
• Package and pinout definition—Develop the package and pin definition file.
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• Extract test vectors—The simulator records the input/output patterns generated during
the real-time simulation. The test vectors that Motorola will use to test the prototypes
are derived from these patterns.
• Post testkit verification—Simulate the design using the extracted test vectors to ensure
proper operation.
• Perform fault grading—Determine the fault coverage of the extracted test vectors.
• Timing constraints—Chip-level timing constraints are created to be used during
floorplanning, clock tree synthesis, placement, and routing.
• Floor planning/Clock tree synthesis—Floor planning and clock tree synthesis are
performed by Motorola using the design timing constraints provided by the designer.
• Automatic place & route—The circuit’s physical layout is created by Motorola from the
netlist using automatic place and route software.
• Post-layout delay calculation—After the cells are placed and routed, the interconnect
resistances and capacitances are extracted by Motorola. Extracted elements replace
those estimated earlier during the pre-layout calculation of the node delays.
• Re-simulate—The circuit is re-simulated with Verilog to ensure no problems have
arisen due to a change in load conditions.
• In-place optimization—If the new delay information causes the simulation to fail,
Synopsys is used to further optimize the layout. Placement and routing is then
repeated. This cycle continues until the final layout, with post-layout delay, satisfies the
design goals.
• Post testkit simulation—Simulate the design using the extracted test vectors to ensure
proper operation.
• Re-extract test vectors—Extract the test vectors again in order to account for timing
changes due to more accurate delay analysis after layout and routing.
• Power simulation—A power simulation is performed to determine if the design meets
the necessary design goals. Power simulation should also be run early in the design
cycle to ensure design goals are met.
• Netlist comparison—The netlist after place and route is compared by Motorola to the
original netlist to check for connectivity errors.
• Pattern, mask, and wafer generation—Motorola generates the patterns, masks, and
wafers.
• Assembly/test—Parts are assembled by Motorola and tested using the test vectors.
• Ship tested prototypes—Tested prototypes are shipped from Motorola to the customer.
• Final test program—The final test is performed by Motorola.
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SCHEMATIC CAPTURE
ON WORKSTATION
VERILOG MODULES
GENERATE TEST PATTERNS
MODULE COMPILATION
FUNCTIONAL SIMULATION
LOGIC SYNTHESIS
ELECTRICAL RULE CHECK
CALCULATE NODE DELAYS
PATH DELAY ANALYSIS
PERFORM REAL-TIME
SIMULATION
TIMING CONSTRAINTS
PACKAGE AND PINOUT
DEFINITION
FLOOR PLANNING /
CLOCK TREE SYNTHESIS
EXTRACT TEST VECTORS
POST TESTKIT VERIFICATION
PERFORM FAULT GRADING
AUTOMATIC PLACE & ROUTE
POST-LAYOUT DELAY
CALCULATION
IN-PLACE OPTIMIZATION
RE-SIMULATE
POST TESTKIT SIMULATION
EXTRACT TEST VECTORS
POWER SIMULATION
NETLIST COMPARISON
PATTERN, MASK AND
WAFER GENERATION
OPTIONAL STEPS TO
BE DONE IN PARALLEL
ASSEMBLY / TEST
STEPS TO BE DONE
IN PARALLEL
SHIP TESTED PROTOTYPES
FINAL TEST PROGRAM
MOTOROLA
CUSTOMER
Figure 1-2. Design System Overview
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1.3 SYSTEM ARCHITECTURE
Most FlexCore custom processors will be designed according to a standard system
architecture. A block diagram of this architecture is shown in Figure 1-3. This architecture
contains the standardized busses and modules discussed below.
I-CACHE
DATA
I-CACHE
TAG
ARRAY
ARRAY
TEST
BUS
EXTERNAL
BUS
SYSTEM
BUS
MASTER
BUS
ARBITER
CONTROLLER
MASTER
BUS
MASTER
BUS
(OPTIONAL)
COLDFIRE2/2M
SLAVE
BUS
SLAVE
MODULE
MASTER
BUS
SLAVE
MODULE
ALTERNATE
MASTER
(OPTIONAL)
SRAM
ARRAY
ROM
ARRAY
SLAVE
MODULE
Figure 1-3. ColdFire2/2M System Diagram
For more information on ColdFire system configurations refer to the MCF5204 User’s
Manual (MCF5204UM/AD) and the MCF5206 User’s Manual (MCF5206UM/AD.)
1.3.1 Internal Bus Structure
1.3.1.1 MASTER BUS. The master bus is the primary data interface for the ColdFire2/2M.
It is a basic two-cycle unidirectional bus. Devices on the master bus are capable of initiating
bus transactions. This bus includes a 32-bit address bus, 32-bit read data bus, 32-bit write
data bus, and various control signals. None of the signals can be tri-stated. As a result, an
optional master bus arbiter is required if multiple masters are present in the system. Refer
to Section 3 Master Bus Operation for more information.
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1.3.1.2 SLAVE BUS. The slave bus is a simplified bus that provides the interface between
the internal master bus and the on-chip peripheral modules. The system bus controller
(SBC) transfers information between the master bus and the slave bus and is the slave bus
master. Only the SBC can initiate slave bus transactions. The slave bus includes device
select lines, interrupt lines, output enables, write enables, interrupt vector enables, and
other control signals to interface to slave modules. All signals are unidirectional and can not
be tri-stated.
1.3.1.3 EXTERNAL BUS. The external bus provides the interface between the internal
master bus and external resources. This bus has no predefined requirements. It can be
asynchronous or synchronous. The address and data bus widths may be different than the
internal master bus. The SBC provides the necessary translation between the master and
external busses.
1.3.1.4 TEST BUS. The test bus provides an interface for performing extensive tests of the
integrated memories. Signals are provided to control reading and writing of the integrated
SRAMs, SROMs, instruction cache tag RAM, and the instruction cache data RAM.
1.3.2 System Functional Blocks
1.3.2.1 ALTERNATE MASTER. Any device that is required to initiate bus transactions is
required to be on the master bus. All master bus devices except the ColdFire2/2M that
initiate bus transactions are considered to be alternate masters. Use of alternate masters
requires a master bus arbiter module. Examples of alternate masters include DMA
controllers and coprocessors.
1.3.2.2 COLDFIRE2/2M. The ColdFire2/2M is the primary CPU for any ColdFire custom
processor. It has dedicated busses for instruction cache and integrated memories. The
master bus is the data interface bus used for all data movement to and from the CPU and
is usually connected to the system bus controller. Clock and debug signals are connected
directly to I/O pins. See Section 2 Signal Summary for more information on all of the
ColdFire2/2M interface signals. A block diagram of the CPU is shown in Figure 1-4.
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COLDFIRE
CORE
INTERNAL
BUS
MULTIPLY
ACCUMULATE
UNIT
(COLDFIRE2M ONLY)
INSTRUCTION
CACHE
CONTROLLER
SRAM
CONTROLLER
ROM
CONTROLLER
SRAM
INTERFACE
ROM
INTERFACE
INSTRUCTION CACHE
INTERFACE
Figure 1-4. ColdFire2/2M Block Diagram
1.3.2.3 I-CACHE DATA ARRAY. The optional instruction cache data array is a compiled
RAM used to hold cache data. It is connected directly to the ColdFire2/2M via a dedicated
bus. Refer to Section 5.1 Instruction Cache for more information on the cache
configuration and interface signals.
1.3.2.4 I-CACHE TAG ARRAY. The optional instruction cache tag array is a compiled
RAM used to hold tag information for the cache. It is connected directly to the ColdFire2/2M
via a dedicated bus. Refer to Section 5.1 Instruction Cache for more information on the
cache configuration and the interface signals.
1.3.2.5 MASTER BUS ARBITER (MARB). The optional master bus arbiter is required to
support multiple masters on the master bus. It performs bus control and multiplexing for the
unidirectional signals on the master bus. Refer to Section 3.10 Master Bus Arbitration for
more information.
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1.3.2.6 ROM ARRAY. The optional ROM array is a compiled ROM used to hold boot code,
critical code, and monitor code. It is connected directly to the ColdFire2/2M via a dedicated
bus. Refer to Section 5.3 ROM Module for more information on the ROM configuration and
the interface signals.
1.3.2.7 SLAVE MODULES. The slave modules are on-chip peripherals. They
communicate with the ColdFire2/2M via the slave bus and SBC. Slave modules are always
bus slaves and cannot initiate bus transactions except via interrupts. Examples of slave
modules include serial ports, parallel ports, and timers.
1.3.2.8 SRAM ARRAY. The optional SRAM array is a compiled RAM used to hold critical
variables and the stack. It is connected directly to the ColdFire2/2M processor via a
dedicated bus. Refer to Section 5.4 SRAM Module for more information on the SRAM
configuration and the interface signals.
1.3.2.9 SYSTEM BUS CONTROLLER (SBC). The system bus controller is responsible for
providing overall control of the slave and external busses. The system bus controller is the
single slave-bus master and interrupt controller, a possible external bus master, bus arbiter
and interrupt controller, and a master-bus slave and interrupt controller. The SBC provides
programmable registers to configure the memory map and interrupt control. The SBC
provides master bus cycle termination for accesses to slave modules on the slave bus. It
also generates interrupts on the master bus when requested by slaves on the slave bus, and
it responds to interrupt acknowledge cycles on the master bus.
1.4 PROGRAMMING MODEL
The ColdFire2/2M programming model consists of three register groups: integer unit user,
MAC unit user, and supervisor. Programs executing in the user mode use only the registers
in the integer and MAC groups. System software executing in the supervisor mode can
access all registers and use the control registers in the supervisor group to perform
supervisor functions. The following paragraphs provide a brief description of the registers in
the user and supervisor models. Refer to Appendix A Register Summary.
1.4.1 Integer Unit User Programming Model
Figure 1-5 illustrates the integer portion of the user programming model. It consists of the
following registers:
• 16 general-purpose 32-bit registers (D0 – D7, A0 – A7)
• 32-bit Program Counter (PC)
• 8-bit Condition Code Register (CCR)
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31
16 15
8
7
0
Data Register 0 (D0)
Data Register 1 (D1)
Data Register 2 (D2)
Data Register 3 (D3)
Data Register 4 (D4)
Data Register 5 (D5)
Data Register 6 (D6)
Data Register 7 (D7)
Address Register 0 (A0)
Address Register 1 (A1)
Address Register 2 (A2)
Address Register 3 (A3)
Address Register 4 (A4)
Address Register 5 (A5)
Address Register 6 (A6)
Stack Pointer (SP,A7)
Program Counter (PC)
Condition Code Register (CCR)
Figure 1-5. Integer Unit User Programming Model
1.4.1.1 DATA REGISTERS (D0 – D7) . Registers D0–D7 are used as data registers for bit
(1 bit), byte (8 bits), word (16 bits), and long word (32 bits) operations and may also be used
as index registers.
1.4.1.2 ADDRESS REGISTERS (A0 – A6) . These registers can be used as software
stack pointers, index registers, or base address registers and may be used for word and long
word operations.
1.4.1.3 STACK POINTER (A7,SP) . ColdFire2/2M supports a single hardware stack
pointer (A7) used during stacking for subroutine calls, returns, and exception handling. The
initial value of A7 is loaded from the reset exception vector, address $0. The same register
is used for user mode and supervisor mode, and may be used for word and long word
operations.
A subroutine call saves the PC on the stack, and the return restores the PC from the stack.
Both the PC and the Status Register (SR) are saved on the stack during the processing of
exceptions and interrupts. The return from exception instruction restores the SR and PC
values from the stack.
1.4.1.4 PROGRAM COUNTER (PC). The PC contains the address of the currently
executing instruction. During instruction execution and exception processing, the processor
automatically increments the contents of the PC or places a new value in the PC, as
appropriate. For some addressing modes, the PC can be used as a pointer for PC-relative
operand addressing.
1.4.1.5 CONDITION CODE REGISTER (CCR). The CCR is the least significant byte of the
processor Status Register (SR), as shown in Figure 1-6. Bits 4–0 represent indicator flags
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based on results generated by processor operations. Bit 4, the extend bit (X bit), is also used
as an input operand during multiprecision arithmetic computations.
BITS
FIELD
RESET
R/W
7
-
6
-
5
-
4
X
3
N
2
Z
1
V
0
C
-
-
-
-
-
-
-
-
R
R
R
R/W
R/W
R/W
R/W
R/W
Figure 1-6. Condition Code Register (CCR)
Field Definitions:
X[4]—Extend Condition Code
Assigned the value of the carry bit for arithmetic operations; otherwise not affected or set to
a specified result.
N[3]—Negative Condition Code
Set if the most significant bit of the result is set; otherwise cleared.
Z[2]—Zero Condition Code
Set if the result equals zero; otherwise cleared.
V[1]—Overflow Condition Code
Set if an arithmetic overflow occurs implying that the result cannot be represented in the
operand size; otherwise cleared.
C[0]—Carry Condition Code
Set if a carryout of the most significant bit of the operand occurs for an addition, or if a borrow
occurs in a subtraction; otherwise cleared.
1.4.2 MAC Unit User Programming Model
Figure 1-7 illustrates the MAC portion of the user programming model available on the
ColdFire2M only. It consists of the following registers:
• 32-bit accumulator (ACC)
• 16-bit mask register (MASK)
• 8-bit MAC status register (MACSR)
31
16 15
8
7
0
Accumulator (ACC)
Mask Register (MASK)
MAC Status Register (MACSR)
Figure 1-7. MAC Unit User Programming Model
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See Section 6.2 MAC Programming Model for more details.
1.4.2.1 ACCUMULATOR (ACC). This is a 32-bit special purpose register used to
accumulate the results of MAC operations.
1.4.2.2 MASK REGISTER (MASK). This is a 16-bit special purpose register used to hold
the address mask for MAC load operations.
1.4.2.3 MAC STATUS REGISTER (MACSR). This is an 8-bit special purpose register
used to hold the status of MAC operations.
1.4.3 Supervisor Programming Model
System programers use the supervisor programming model to implement sensitive
operating system functions. The following paragraphs briefly describe the registers in the
supervisor programming model. All accesses that affect the control features of the
ColdFire2/2M are in the supervisor programming model, which consist of the registers
available to users as well as the registers listed in Figure 1-8.
31
16 15
0
Cache Control Register (CACR)
Access Control Register 0 (ACR0)
Access Control Register 1 (ACR1)
Vector Base Register (VBR)
ROM Base Address Register (ROMBAR0)
SRAM Base Address Register (RAMBAR0)
Status Register (SR)
Figure 1-8. Supervisor Programming Model
Most of the control registers are accessed via the MOVEC instruction using the control
register definitions shown in Table 1-1. These are a subset of the registers defined in the
ColdFire Programmer’s Reference Manual Rev. 1.0 (MCF5200PRM/AD).
Table 1-1. MOVEC Register Map
RC[11:0]
$002
REGISTER DEFINITION
Cache Control Register (CACR)
$004
Access Control Register 0 (ACR0)
Access Control Register 1 (ACR1)
Vector Base Register (VBR)
$005
$801
$C00
$C04
ROM Base Address Register (ROMBAR0)
RAM Base Address Register 0 (RAMBAR0)
Refer to Appendix A Register Summary for a description of the access methods for all of
the register in the ColdFire2/2M.
1.4.3.1 STATUS REGISTER (SR). Figure 1-9 illustrates the SR, which stores the
processor status and contains the condition codes that reflect the results of a previous
operation. The low-order byte of the SR is the condition code register (CCR.)
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BITS
FIELD
RESET
R/W
15
T
14
-
13
S
12
M
11
-
10
8
7
5
4
X
3
N
2
Z
1
V
0
C
I
7
-
0
0
1
1
0
0
R
0
0
0
0
0
R/W
R
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
Figure 1-9. Status Register (SR)
Field Definitions:
T[15]—Trace Enable
When set, the processor will perform a trace exception after every instruction; otherwise no
trace exception is performed.
S[13]—Supervisor / User State
Denotes the processor privilege mode: supervisor mode (S set) or user mode (S cleared).
M[12]—Master / Interrupt State
This bit is cleared by an interrupt exception, and can be set by software during execution of
the RTE or move to SR instructions.
I[10:8]—Interrupt Priority Mask
Defines the current interrupt priority. Interrupt requests are inhibited for all priority levels less
than or equal to the current priority, except the level seven request, which cannot be
masked.
1.4.3.2 CACHE CONTROL REGISTER (CACR). The CACR controls the cache operation.
This includes cache enable, cache freeze, cache invalidate, cache mode, and default write
protect. See Section 5.1.11 Cache Control Register (CACR) for more information.
1.4.3.3 ACCESS CONTROL REGISTERS (ACR0, ACR1). The ACRs allow definition of
access attributes for two definable memory regions. These attributes include burst control,
instruction caching, and write protection. These attributes override the defaults in the CACR.
See Section 5.2.1 ACR Programming Model for more information.
1.4.3.4 VECTOR BASE REGISTER (VBR). The VBR contains the base address of the
exception vector table in memory. The displacement of an exception vector is added to the
value in this register to access the vector table. Only the upper 12 bits of the VBR are used
and the lower 20 bits are filled with zeros. This forces the exception vector table to be aligned
on a 1 MByte boundary. This register is reset to zero.
1.4.3.5 ROM BASE ADDRESS REGISTER (ROMBAR0). The ROMBAR0 register
configures the internal ROM module. This includes the base address, code space masks,
and enable. See Section 5.3.2 ROM Programming Model for more information.
1.4.3.6 SRAM BASE ADDRESS REGISTER (RAMBAR0). The RAMBAR0 register
configures the internal SRAM module. This includes the base address, write protect, code
MOTOROLA
ColdFire2/2M User’s Manual
1-15
Overview
space masks, and enable. See Section 5.4.3 RAM Programming Model for more
information.
1.5 INTEGER DATA FORMATS
Table 1-2 lists the operand data formats that are supported by the integer unit. Integer unit
operands can reside in registers, memory, or instructions. The operand size for each
instruction is either explicitly encoded in the instruction or implicitly defined by the instruction
operation.
Table 1-2. Integer Data Formats
OPERAND DATA FORMAT
Bit
SIZE
1 Bit
Byte Integer
8 Bits
16 Bits
32 Bits
Word Integer
Long-Word Integer
1.6 ORGANIZATION OF DATA IN REGISTERS
The following paragraphs describe data organization within the data, address, and control
registers.
1.6.1 Organization of Integer Data Formats in Registers
Figure 1-10 shows the integer format for data registers. Each integer data register is 32 bits
wide. Byte and word operands occupy the lower 8- and 16-bit portions of integer data
registers, respectively. Long-word operands occupy the entire 32 bits of integer data
registers. A data register that is either a source or destination operand only uses or changes
the appropriate lower 8 or 16 bits in byte or word operations, respectively. The remaining
high-order portion does not change. The least significant bit (LSB) of all integer sizes is zero,
the most significant bit (MSB) of a longword integer is 31, the MSB of a word integer is 15,
and the MSB of a byte integer is 7.
31
1
0
30
_
<
BIT (0 MODULO (OFFSET)
LSB
MSB
< 31,OFFSET OF 0 = MSB)
31
7
0
BYTE
NOT USED
MSB
LSB
31
0
15
16-BIT WORD
LONG WORD
LSB
LOW-ORDER WORD
NOT USED
MSB
31
0
MSB
LSB
LONG WORD
Figure 1-10. Organization of Integer Data Formats in Data Registers
Because address registers and stack pointers are 32-bits wide, address registers cannot be
used for byte-size operands. When an address register is a source operand, either the low-
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ColdFire2/2M User’s Manual
MOTOROLA
Overview
order word or the entire longword operand is used, depending on the operation size. When
an address register is the destination operand, the entire register becomes affected, despite
the operation size. If the source operand is a word size, it is sign-extended to 32 bits and
then used in the operation to an address register destination. Address registers are primarily
for addresses and address computation support. The instruction set (See Section 1.8
Instruction Set Summary) explains how to add, compare, and move the contents of
address registers. Figure 1-11 illustrates the integer format for address registers.
31
16
15
0
SIGN-EXTENDED
16-BIT ADDRESS OPERAND
31
0
FULL 32-BIT ADDRESS OPERAND
Figure 1-11. Organization of Integer Data Formats in Address Registers
Control registers vary in size according to function. Some control registers have undefined
bits reserved for future definition by Motorola. Those particular bits read as zeros and must
be written as zeros for future compatibility.
All operations to the SR and CCR are word-size operations. For all CCR operations, the
upper byte is read as all zeros and is ignored when written, despite privilege mode.
1.6.2 Organization of Integer Data Formats in Memory
The ColdFire2/2M uses a big-endian addressing scheme. The byte-addressable
organization of memory allows lower addresses to correspond to higher order bytes. The
address N of a long-word data item corresponds to the address of the high order word. The
lower order word is located at address N + 2. The address N of a word data item
corresponds to the address of the high order byte. The lower order byte is located at address
N + 1. This organization is shown in Figure 1-12.
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ColdFire2/2M User’s Manual
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Overview
31
23
15
7
0
LONG WORD $00000000
WORD $00000000
WORD $00000002
BYTE $00000000
BYTE $00000001
BYTE $00000002
BYTE $00000003
BYTE $00000007
LONG WORD $00000004
WORD $00000004
BYTE $00000004 BYTE $00000005
WORD $00000006
BYTE $00000006
LONG WORD $FFFFFFFC
WORD $FFFFFFFC
BYTE $FFFFFFFC BYTE $FFFFFFFD
WORD $FFFFFFFE
BYTE $FFFFFFFE
BYTE $FFFFFFFF
Figure 1-12. Memory Operand Addressing
1.7 ADDRESSING MODE SUMMARY
The addressing modes are grouped into categories according to the mode of use. Data
addressing modes refer to data operands. Memory addressing modes refer to memory
operands. Alterable addressing modes refer to alterable (writable) operands. Control
addressing modes refer to memory operands without an associated size.
These categories sometimes combine to form new categories that are more restrictive. Two
combined classifications are alterable memory (both alterable and memory) and data
alterable (both alterable and data). Table 1-3 lists a summary of effective addressing modes
and their categories. Only the twelve addressing modes supported by the 68000 are
available on the ColdFire2/2M.
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ColdFire2/2M User’s Manual
MOTOROLA
Overview
Table 1-3. Effective Addressing Modes and Categories
CATEGORY
CONTROL
MODE
FIELD
REG.
FIELD
ADDRESSING MODES
SYNTAX
DATA
MEMORY
ALTERABLE
Register Direct
Data
Dn
An
000
001
reg. no.
reg. no.
X
—
—
—
—
X
X
Address
—
Register Indirect
Address
(An)
(An)+
–(An)
010
011
100
101
reg. no.
reg. no.
reg. no.
reg. no.
X
X
X
X
X
X
X
X
X
—
—
X
X
X
X
X
Address with Postincrement
Address with Predecrement
Address with Displacement
(d , An)
16
Address Register Indirect with Index
8-Bit Displacement
(d , An, Xn)
110
111
111
reg. no.
010
X
X
X
X
X
X
X
X
X
X
8
Program Counter Indirect
with Displacement
(d , PC)
—
—
16
Program Counter Indirect with Index
8-Bit Displacement
(d , PC, Xn)
8
011
Absolute Data Addressing
Short
Long
(xxx).W
(xxx).L
111
111
000
001
X
X
X
X
X
X
—
—
Immediate
#<xxx>
111
100
X
X
—
—
1.8 INSTRUCTION SET SUMMARY
Table 1-4 lists the notational conventions used throughout this manual unless otherwise
specified. Table 1-5 lists the ColdFire2/2M instruction set by opcode. This instruction set is
a reduced version of the 68000 instruction set. The removed instructions include BCD, bit
field, logical rotate, decrement and branch, integer division, and integer multiply with a 64-
bit result. Nine new MAC instructions have been added.
Table 1-4. Notational Conventions
OPCODE WILDCARDS
cc
Logical Condition (example: NE for not equal)
REGISTER OPERANDS
An
Ay,Ax
Dn
Any Address Register n (example: A3 is address register 3)
Source and destination address registers, respectively
Any Data Register n (example: D5 is data register 5)
Source and destination data registers, respectively
Any Address or Data Register
Dy,Dx
Rn
Ry,Rx
Rw
Any source and destination registers, respectively
Any second source register
Rc
Any Control Register (example VBR is the vector base register)
REGISTER/PORT NAMES
MAC Accumulator
ACC
DDATA
CCR
Debug Data Port
Condition Code Register (lower byte of status register)
MAC Status Register
Mask Register
MACSR
MASK
PC
Program Counter
PST
Processor Status Port
Status Register
SR
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ColdFire2/2M User’s Manual
1-19
Overview
Table 1-4. Notational Conventions (Continued)
MISCELLANEOUS OPERANDS
#<data>
Immediate data following the instruction word(s).
Effective Address
<ea>
<label>
<list>
Assemble Program Label
List of registers (example: D3–D0)
Shift operation: Shift left (<<), Shift Right (>>)
Operand data size: Byte (B), Word (W), Longword (L)
<shift>
<size>
OPERATIONS
Arithmetic addition or postincrement indicator
Arithmetic subtraction or predecrement indicator
Arithmetic multiplication
+
–
¥
~
L
V
Invert; operand is logically complemented
Logical AND
Logical OR
Logical exclusive OR
<<
>>
Shift left (example: D0 << 3 is shift D0 left 3 bits)
Shift right (example: D0 >> 3 is shift D0 right 3 bits)
Source operand is moved to destination operand
Two operands are exchanged
→
←→
sign-extended
All bits of the upper portion are made equal to the high-order bit of the lower portion
If <condition>
Test the condition. If true, the operations after ‘then’ are performed. If the condition is false and the optional ‘else’ clause
is present, the operations after ‘else’ are performed. If the condition is false and else is omitted, the instruction performs no
operation. Refer to the Bcc instruction description as an example.
then <operations>
else <operations>
&
|
and
or
SUBFIELDS AND QUALIFIERS
Optional Operation
{}
()
Identifies an indirect address
d
Displacement Value, n-Bits Wide (example: d is a 16-bit displacement)
16
n
Address
Bit
Calculated Effective Address (pointer)
Bit Selection (example: Bit 3 of D0)
Least Significant Bit (example: MSB of D0)
Least Significant Word
LSB
LSW
MSB
MSW
Most Significant Bit
Most Significant Word
CONDITION CODE REGISTER BIT NAMES
Carry Bit in CCR
C
N
V
X
Z
Negative Bit in CCR
Overflow Bit in CCR
Extend Bit in CCR
Zero Bit in CCR
1-20
ColdFire2/2M User’s Manual
MOTOROLA
Overview
Table 1-5. Instruction Set Summary
INSTRUCTION
OPERAND SYNTAX
OPERAND SIZE
OPERATION
ADD
Dy,<ea>,x
<ea>y,Dx
32
32
Source + Destination → Destination
ADDA
ADDI
ADDQ
ADDX
AND
<ea>y,Ax
#<data>,Dx
#<data>,<ea>x
Dy,Dx
32
32
32
32
Source + Destination → Destination
Immediate Data + Destination → Destination
Immediate Data + Destination → Destination
Source + Destination + X → Destination
Source L Destination → Destination
Dy,<ea>x
<ea>y,Dx
32
32
ANDI
ASL
#<data>,Dx
32
Immediate Data L Destination → Destination
Dx,Dy
#<data>,Dn
32
32
X/C
X/C
←
(Dy << Dx)
←
0
←
(Dy << #<data>)
←
0
ASR
Dx,Dy
<data>,Dx
32
32
MSB
MSB
→
(Dy >> Dx)
→
X/C
→ X/C
→
(Dy >> #<data>)
Bcc
<label>
8,16
If Condition True, Then PC + d
→
PC
n
BCHG
Dy,<ea>x
8,32
8,32
~(<Bit Number> of Destination)
~(<Bit Number> of Destination)
PC + d
→ Z, Bit of Destination
#<data>,<ea>x
BCLR
Dy,<ea>x
8,32
8,32
→
Z, 0
→
→
Bit of Destination
#<data>,<ea>x
BRA
<label>
8,16
→
PC
Z, 1
n
BSET
Dy,<ea>x
8,32
8,32
~(<Bit Number> of Destination) →
Bit of Destination
#<data>,<ea>x
BSR
<label>
8,16
SP – 4
→ SP; PC → (SP); PC + d → PC
n
BTST
Dy,<ea>x
8,32
8,32
~(<Bit Number> of Destination) → Z
#<data>,<ea>x
CLR
CMPI
CMP
<ea>x
#<data>,Dx
<ea>y,Dx
<ea>y,Ax
(An)
8,16,32
8,16,32
32
0 → Destination
Destination – Immediate Data
Destination - Source
CMPA
CPUSH
EOR
32
Destination - Source
32
Push and Invalidate Cache Line
Dy,<ea>x
#<data>,Dx
32
Source Destination → Destination
Immediate Data Destination Destination
EORI
EXT
32
→
Dx
Dx
8
→
16
32
Sign-Extended Destination
→
Destination
16
→
EXTB
HALT
JMP
JSR
Dx
none
8
→
32
Sign-Extended Destination
→
Destination
none
none
none
32
Enter Halted State
<ea>y
<ea>y
→
→
PC
(SP); <ea>y
An
Ax; SP + d16 → SP
<ea>y
SP – 4
→
SP; Next PC
→ PC
LEA
<ea>y,Ax
Ax,#<data>
Address of <ea>
SP; Ax (SP); SP
(Dy << Dx)
→
LINK
LSL
32
SP – 4
→
→
→
Dx,Dy
32
32
X/C
←
←
0
#<data>,Dx
X/C
0
←
→
(Dx << #<data>)
(Dy >> Dx)
←
0
LSR
Dx,Dy
32
32
→
X/C
#<data>,Dx
0
→
(Dx >> #<data>)
→
X/C
MAC
MACL
†
Rw,Rx ,<shift>
16
32
×
×
16 + 32 → 32
32 + 32 → 32
ACC + (Rw
×
Rx){ << 1 | >> 1}
→
ACC
†
Rw,Rx,<shift>,<ea>,Ry 16
32
×
×
16 + 32 → 32
32 + 32 → 32
ACC + (Rw
×
Rx){ << 1 | >> 1}
→
ACC; (<ea>{& MASK})
→
Ry
MOVE
<ea>y,<ea>x
ACC,Rx
Dx
8,16,32
32
Source
ACC
CCR Destination
→
Destination
MOVE from ACC
†
→ Rn
MOVE from CCR
16
→
NOTE:
†Available on the ColdFire2M only.
MOTOROLA
ColdFire2/2M User’s Manual
1-21
Overview
Table 1-5. Instruction Set Summary (Continued)
INSTRUCTION
MOVE from MACSR
OPERAND SYNTAX
OPERAND SIZE
OPERATION
†
MACSR,Rx
MACSR,CCR
32
8
MACSR
→
Rx
MACSR
→
CCR
MOVE from MASK
†
MASK,Rx
Dx
32
16
MASK →
Rx
MOVE from SR
SR
→
Destination
MOVE to ACC
†
Rx,ACC
32
32
Rx
→
ACC
#<data>,ACC
#<data>
→
ACC
MOVE to CCR
Dy,CCR,
16
Source
→
→
CCR
CCR
#<data>,CCR
#<data>
MOVE to MACSR
†
Rn,MACSR
32
Rn
→
MACSR
#<data>,MACSR
#<data>
→ MACSR
MOVE to MASK
†
Rn,MASK
32
32
Rn
→
MASK
#<data>,MASK
#<data>
→ MASK
MOVE to SR
Dy,SR
16
Source
→
SR
SR
#<data>,SR
#<data> →
MOVEA
MOVEC
MOVEM
<ea>y,Ax
Rn,Rc
16,32
→
32
Source
Rn
Listed Registers
Source Listed Registers
Sign-extended Immediate Data Destination
ACC - (Rw Rx){ << 1 | >> 1} SF ACC
→
Destination
Rc
Destination
32
→
list,<ea>x
<ea>y,list
32
32
→
→
MOVEQ
#<data>,Dx
8
→
32
→
MSAC
†
Rw,Rx,<shift>
32 - 16
32 - 32
×
×
16
→
→
32
32
×
→
32
MSACL
†
Rw,Rx,<shift>,<ea>,Ry
32 - 16
32 - 32
×
×
16
32
→
→
32
32
ACC - (Rw × Rx){ << 1 | >> 1} SF → ACC; (<ea>{& MASK}) → Ry
MULS
<ea>y,Dx
<ea>y, DI
16 x 16
32 x 32
→
→
32
32
Source
×
Destination
→ Destination
(Signed or unsigned)
MULU
<ea>y,Dx
<ea>y, DI
16 x 16
32 x 32
→
32
32
Source x Destination Destination
→
→
(Signed or unsigned)
0 – Destination Destination
0 – Destination – X Destination
PC + 2 PC; Pipeline synchronized
~ Destination Destination
Source Destination
NEG
NEGX
NOP
NOT
OR
<ea>x
<ea>x
none
32
→
32
none
32
→
→
<ea>x
→
Dy,<ea>x
<ea>y,Dx
32
V
→
Destination
ORI
PEA
#<data>,Dx
<ea>y
none
32
32
Immediate Data
SP – 4
Generate unique PST value
SR; (SP+4) PC; SP+ 8
(SP) PC; SP + 4 SP
If condition true, then 1's Destination;
V
Destination
→
Destination
→
SP; <ea>y → (SP)
PULSE
RTE
none
none
none
8
none
(SP+2)
→
→
→ PC
RTS
none
→
→
Scc
Dx
→
Else 0's Destination
→
STOP
SUB
#<data>
16
Immediate data SR; Enter Stopped State
→
Dy,<ea>x
<ea>y,Dx
32
32
Destination - Source
→
Destination
SUBA
SUBI
<ea>,Ax
#<data>,Dx
#<data>,<ea>x
Dy,Dx
32
32
Destination - Source
→
Destination
Destination – Immediate data
Destination – Immediate data
→
→
Destination
Destination
SUBQ
SUBX
SWAP
TRAP
32
32
Destination – Source – X
→ Destination
Dx
16
MSW of Dx ←→ LSW of Dx
none
none
SP – 4
SP – 2
→
SP; PC
SP; SR
→
→
(SP);
(SP);
→
SP – 2
→
SP; Format
→
(SP);
Vector Address
→ PC
NOTE:
†Available on the ColdFire2M only.
1-22
ColdFire2/2M User’s Manual
MOTOROLA
Overview
Table 1-5. Instruction Set Summary (Continued)
INSTRUCTION
OPERAND SYNTAX
OPERAND SIZE
OPERATION
TRAPF
none
none
16
PC + 2
→
PC;
PC;
PC
#<data>
PC + 4
→
32
PC + 6→
TST
<ea>y
Ax
8,16,32
32
Set Integer Condition Codes
SP; (SP) Ax; SP + 4
(<ea>y) DDATA port
DEBUG; <ea>y + 4 → DEBUG
UNLK
Ax
→
→
→ SP
WDDATA
WDEBUG
<ea>y
<ea>y
8,16,32
64
→
<ea>y
→
NOTE:
†Available on the ColdFire2M only.
MOTOROLA
ColdFire2/2M User’s Manual
1-23
SECTION 2
SIGNAL SUMMARY
2.1 INTRODUCTION
This section describes the ColdFire2/2M input and output signals. Figure 2-1 shows the
ColdFire2/2M along with the signal interface. The signals are listed alphabetically in Table
2-1. All ColdFire2/2M signals are unidirectional and synchronous.
BKPTB
DSCLK
DSI
MADDR[31:0]
MARBC[1:0]
MFRZB
MKILLB
MRWB
I-CACHE
UNIT
DEBUG
UNIT
DSO
DDATA[3:0]
PST[3:0]
MSIZ[1:0]
MTM[2:0]
MTSB
MTT[1:0]
MWDATA[31:0]
CPU
MWDATAOE
MRDATA[31:0]
MIE
CORE
MTAB
MTEAB
MRSTB
TEST_ADDR[14:2]
TEST_CTRL
TEST_RHIT
MAC UNIT
TEST_IVLD_INH
TEST_ITAG_WRT
TEST_IDATA_RD
TEST_IDATA_WRT
TEST_KTA
(COLDFIRE2M)
TEST
PORT
TEST_MODE
TEST_SRAM_RD
TEST_SRAM_WRT
TEST_RD
TEST_ROM_RD
TEST_WR_INH
SRAM
UNIT
ROM
UNIT
Figure 2-1. ColdFire2/2M Detailed Block Diagram
MOTOROLA
ColdFire2/2M User’s Manual
2-1
Signal Summary
Table 2-1. Signal Summary
SIGNAL
MNEMONIC
IACK_68K
BKPTB
INPUT/OUTPUT
Input
ACTIVE STATE
High
Low
68K Interrupt Acknowledge Mode
Break Point
Input
Clock
CLK
Input
High
High
High
High
High
High
Low
Debug Data
DDATA[3:0]
DSCLK
Output
Input
Development Serial Clock
Development Serial Data Input
Development Serial Data Output
Instruction Cache Address Bus
Instruction Cache Data Chip-Select
Instruction Cache Data Input Bus
Instruction Cache Data Output Bus
Instruction Cache Data Strobe
Instruction Cache Data Write Enable
Instruction Cache Size
Instruction Cache Tag Chip-Select
Instruction Cache Tag Input Bus
Instruction Cache Tag Output Bus
Instruction Cache Tag Strobe
Instruction Cache Tag Write Enable
Interrupt Priority Level
Master Address Bus
DSI
Input
DSO
Output
Output
Output
Output
Input
ICH_ADDR[14:2]
ICHD_CSB
ICHD_DI[31:0]
ICHD_DO[31:0]
ICHD_ST
ICHD_RWB
ICH_SZ[2:0]
ICHT_CSB
ICHT_DI[31:8]
ICHT_DO[31:8]
ICHT_ST
High
High
High
Low
Output
Output
Input
High
Low
Output
Output
Input
High
High
High
Low
Output
Output
Input
ICHT_RWB
IPLB[2:0]
Low
MADDR[31:0]
MARBC[1:0]
MFRZB
Output
Output
Output
Output
Input
High
High
Low
Master Arbiter Control
Master Freeze
Master Kill
MKILLB
Low
Master Read Data Bus
Master Read Data Input Enable
Master Read/Write
MRDATA[31:0]
MIE
High
High
Low
Input
MRWB
Output
Input
Master Reset
MRSTB
Low
Master Size
MSIZ[1:0]
Output
Input
High
Low
Master Transfer Acknowledge
Master Transfer Error Acknowledge
Master Transfer Modifier
Master Transfer Start
Master Transfer Type
Master Write Data Bus
Master Write Data Output Enable
Processor Status
MTAB
MTEAB
Input
Low
MTM[2:0]
Output
Output
Output
Output
Output
Output
Output
Input
High
Low
MTSB
MTT[1:0]
High
High
High
High
High
High
Low
MWDATA[31:0]
MWDATAOE
PST[3:0]
ROM Address Bus
ROM_ADDR[14:2]
ROM_DO[31:0]
ROM_ENB[1:0]
ROM_SZ[2:0]
ROM_VLD
SCAN_ENABLE
SCAN_XARRAY
SI[15:0]
ROM Data Output Bus
ROM Enable
Output
Input
ROM Size
High
High
High
High
High
High
High
High
ROM Valid
Input
Scan Enable
Input
Scan Exercise Array
Input
Scan Input
Input
Scan Mode
SCAN_MODE
SO[15:0]
Input
Scan Output
Input
Scan Test Ring Clock
TR_CLK
Input
2-2
ColdFire2/2M User’s Manual
MOTOROLA
Signal Summary
Table 2-1. Signal Summary (Continued)
SIGNAL
Scan Test Ring Core Mode Enable
Scan Test Ring Data Input
Scan Test Ring Data Output
Scan Test Ring Enable
Scan Test Ring Mode
SRAM Address Bus
SRAM Chip-Select
SRAM Data Input Bus
SRAM Data Output Bus
SRAM Size
MNEMONIC
CORE_TEST
INPUT/OUTPUT
ACTIVE STATE
High
High
High
High
High
High
Low
Input
Input
TR_SDI[1:0]
TR_SDO[1:0]
Output
Input
TR_SE
TR_MODE
Input
SRAM_ADDR[14:2]
SRAM_CSB
Output
Output
Output
Input
SRAM_DI[31:0]
SRAM_DO[31:0]
SRAM_SZ[2::0]
SRAM_ST[3::0]
SRAM_RWB[3:0]
TEST_ADDR[14:2]
TEST_CTRL
High
High
High
High
Low
Input
SRAM Strobe
Output
Output
Input
SRAM Read/Write
Test Address Bus
High
High
High
High
High
High
High
High
High
High
High
High
High
High
Test Control
Input
Test Invalidate Inhibit
Test ITAG Write
TEST_IVLD_INH
TEST_ITAG_WRT
TEST_RHIT
Input
Input
Test Instruction Cache Read Hit
Test IDATA Read
Output
Input
TEST_IDATA_RD
TEST_IDATA_WRT
TEST_KTA
Test IDATA Write
Input
Test KTA Mode Enable
Test Mode Enable
Input
TEST_MODE
TEST_SRAM_RD
TEST_SRAM_WRT
TEST_RD
Input
Test SRAM Read
Input
Test SRAM Write
Input
Test Read
Input
Test ROM Read
TEST_ROM_RD
TEST_WR_INH
Input
Test Write Inhibit
Input
2.2 MASTER BUS SIGNALS
2.2.1 68K Interrupt Acknowledge Mode Enable (IACK_68K)
This active-high input signal enables the 68K interrupt acknowledge mode. In this mode, the
Master Address Bus, MADDR[31:0], MTT[1:0], and MTM[2:0] signals mimic the 68K
address bus and function codes during interrupt acknowledge and CPU space bus cycles.
This is a static input. Refer to Section 3.7.1 Interrupt Acknowledge Bus Cycle for more
information.
2.2.2 Master Address Bus (MADDR[31:0])
During a normal bus cycle, this 32-bit output bus provides the address of the first item of a
bus transfer. It is capable of addressing 4 Gbytes of address space.
2.2.3 Master Arbiter Control (MARBC[1:0])
These output signals can be used to specify the mode of operation for an optional arbitration
module. They reflect the bit positions [17:16] in the CACR. If an optional arbitration module
is not used, these signals can be used as general purpose output signals. The CACR is
accessible in supervisor mode as control register $002 using the MOVEC instruction.
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Signal Summary
2.2.4 Master Freeze (MFRZB)
This active-low output signal indicates that the core has been halted. MFRZB is not part of
the M-Bus protocol. It is simply a signal that can be used to alert timers or other peripheral
modules that the core has been halted.
2.2.5 Master Kill (MKILLB)
This active-low output signal qualifies MTSB (i.e. it can assert in other cycles but is only
significant in a cycle where MSTB is asserted). When MKILLB is asserted simultaneously
with MTSB assertion, this indicates a hit in a K-Bus memory and that the external cycle must
be inhibited. This means the current master bus transaction is no longer required and should
be ignored (MTAB should not be asserted). MKILLB is asserted late in the MTSB cycle. Note
that if there is no K-Bus resident memory (ICACHE, SRAM, or ROM), MKILLB never
asserts. See Table 2-2 for MTSB/MKILLB interaction in table format.
Table 2-2. M-Bus Protocol with respect to MTSB and MKILLB
MTSB
MKILLB
M-BUS PROTOCOL
0
0
1
1
0
X
Initiate M-Bus transfer
Nop
Nop
2.2.6 Master Read Data Bus (MRDATA[31:0])
These input signals provide the read data path between the system and the ColdFire2/2M.
The read data bus is 32-bits wide and can transfer 8, 16 or 32 bits of data per bus transfer.
During a line transfer, the data bus is time-multiplexed across multiple clock cycles to
transfer 128 bits.
2.2.7 Master Read Data Input Enable (MIE)
This active-high input signal enables the capturing of MRDATA[31:0]. Power consumption
can be reduced by minimizing signal switching in the ColdFire2/2M by negating MIE when
MRDATA[31:0] is invalid. MIE must be asserted during all functional operation with one
master and during K-Bus memory testing.
2.2.8 Master Read/Write (MRWB)
This output signal indicates the direction of the data transfer for the current bus cycle. A high
level indicates a read cycle and a low level indicates a write cycle.
2.2.9 Master Reset (MRSTB)
This active-low input signal instructs all master bus modules, including the ColdFire2/2M, to
enter reset mode. The ColdFire2/2M will then initiate a reset exception.
2.2.10 Master Size (MSIZ[1:0])
These output signals indicate the data size for the bus transfer. Refer to Table 2-3 for the
bus size encoding.
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Signal Summary
Table 2-3. Master Bus Transfer Size Encoding
MSIZ[1:0]
TRANSFER SIZE
Longword (4 bytes)
Byte (1 byte)
00
01
10
11
Word (2 bytes)
Line (16 bytes)
2.2.11 Master Transfer Acknowledge (MTAB)
This active-low input signal is asserted by master bus slaves to indicate the successful
completion of a requested bus transfer.
2.2.12 Master Transfer Error Acknowledge (MTEAB)
This active-low input signal is asserted by master bus slaves to indicate an error condition
for the current bus transfer. If MTAB and MTEAB are both asserted, the cycle is terminated
with an error because MTEAB always has precedence over MTAB.
2.2.13 Master Transfer Modifier (MTM[2:0])
These output signals provide supplemental information for each transfer type. The exact
meaning depends on the MTT[1:0], and IACK_68K signals as shown in Table 2-4.
Table 2-4. Master Bus Transfer Modifier Encoding
1
2
MTM[2:0] MTT[1:0]
COLDFIRE IACK MODE
Reserved
68K IACK MODE
000
001
0x
0x
0x
0x
0x
0x
0x
10
10
10
10
11
11
11
11
11
11
11
11
Reserved
User Data Access
User Code Access
Reserved
User Data Access
User Code Access
Reserved
010
011 - 100
101
Supervisor Data Access
Supervisor Data Access
Supervisor Code Access
Interrupt Acknowledge/CPU Space Access
Reserved
110
Supervisor Code Access
Reserved
111
000 - 100
101
Reserved
Emulator Mode Data Access
Emulator Mode Code Access
Reserved
Emulator Mode Data Access
Emulator Mode Code Access
Reserved
110
111
000
CPU Space Access
Reserved
001
Interrupt Acknowledge Level 1
Interrupt Acknowledge Level 2
Interrupt Acknowledge Level 3
Interrupt Acknowledge Level 4
Interrupt Acknowledge Level 5
Interrupt Acknowledge Level 6
Interrupt Acknowledge Level 7
Reserved
010
Reserved
011
Reserved
100
Reserved
101
Reserved
110
Reserved
111
Reserved
NOTES: 1. 68K interrupt acknowledge mode signal negated (IACK_68K = 0)
2. 68K interrupt acknowledge mode signal asserted (IACK_68K = 1)
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Signal Summary
2.2.14 Master Transfer Start (MTSB)
This active-low output signal indicates the start of each bus transfer.
2.2.15 Master Transfer Type (MTT[1:0])
These output signals indicate the type of access of the current bus cycle. The exact meaning
depends on the IACK_68K signal as shown in Table 2-5.
Table 2-5. Master Bus Transfer Type Encoding
1
2
MTT[1:0]
COLDFIRE IACK MODE
68K IACK MODE
00
01
10
11
ColdFire2/2M Access
Acknowledge/CPU Space/ColdFire2/2M Access
Alternate Master Access
Emulator Mode Access
Alternate Master Access
Emulator Mode Access
Acknowledge/CPU Space Access
Reserved
NOTES: 1. 68K interrupt acknowledge mode signal negated (IACK_68K = 0)
2. 68K interrupt acknowledge mode signal asserted (IACK_68K = 1)
2.2.16 Master Write Data Bus (MWDATA[31:0])
These output signals provide the write data path between the ColdFire2/2M and the system.
The write data bus is 32-bits wide and can transfer 8, 16 or 32 bits of data per bus transfer.
During a line transfer, the data bus is time-multiplexed across multiple clock cycles to carry
128 bits.
2.2.17 Master Write Data Output Enable (MWDATAOE)
This active-high output signal indicates that the ColdFire2/2M is driving the master write data
bus. This is used to control optional bidirectional data bus three-state drivers.
2.3 GENERAL CONTROL SIGNALS
2.3.1 Clock (CLK)
This input signal is the synchronous clock for the ColdFire2/2M. CLK is used to clock or
sequence the ColdFire2/2M internal logic.
2.3.2 Interrupt Priority Level (IPLB[2:0])
These active-low input signals indicate the encoded priority level of the requested interrupt.
Level seven, which cannot be masked, has the highest priority. Level zero indicates no
interrupt has been requested. These signals must maintain the interrupt request until the
ColdFire2/2M acknowledges the interrupt to guarantee that the interrupt is recognized.
Table 2-6 lists the interrupt levels, the IPLB[2:0] states, and the mask value that allows an
interrupt at each level.
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Signal Summary
Table 2-6. Interrupt Levels and Mask Values
CONTROL LINE STATUS
INTERRUPT MASK LEVEL
REQUESTED
INTERRUPT LEVEL
REQUIRED FOR RECOGNITION
IPLB[2] IPLB[1] IPLB[0]
0
1
2
3
4
5
6
7
High
High
High
High
Low
Low
Low
Low
High
High
Low
Low
High
High
Low
Low
High
Low
High
Low
High
Low
High
Low
No Request
0
0-1
0-2
0-3
0-4
0-5
0-7
2.4 INTEGRATED MEMORY SIGNALS
These signals interface the ColdFire2/2M to an integrated instruction cache, ROMs and
SRAMs.
2.4.1 Instruction Cache Signals
The signals interface the ColdFire2/2M to an optional integrated instruction cache.
2.4.1.1 INSTRUCTION CACHE ADDRESS BUS (ICH_ADDR[14:2]). These registered
output signals provide the address of the current bus cycle (i.e. fetch cycle) to the integrated
cache RAMs. ICH_ADDR is only updated on fetch cycles (i.e. ICH_ADDR does not get
updated on SRAM or ROM hits). This bus should be connected to the address bus (A) of
the two compiled cache RAMs.
2.4.1.2 INSTRUCTION CACHE DATA CHIP-SELECT (ICHD_CSB). This active-low,
output signal indicates the cache data RAM is currently selected to perform a data transfer
with the ColdFire2/2M. This bus should be connected to the chip-select (CSB) signal of the
compiled cache data RAM.
2.4.1.3 INSTRUCTION CACHE DATA INPUT BUS (ICHD_DI[31:0]). These output
signals provide the write data path between the ColdFire2/2M and the cache data RAM. The
data bus is 32-bits wide and should be connected to the data inputs (DBI) of the compiled
cache data RAM.
2.4.1.4 INSTRUCTION CACHE DATA OUTPUT BUS (ICHD_DO[31:0]). These input
signals provide the read data path between the cache data RAM and the ColdFire2/2M. The
data bus is 32-bits wide and should be connected to the data outputs (DBO) of the compiled
cache data RAM.
2.4.1.5 INSTRUCTION CACHE DATA STROBE (ICHD_ST). This output signal initiates a
read or write cycle to the cache data RAM on a low-to-high transition. This signal should be
connected to the strobe input (ST) signal of the compiled cache data RAM.
2.4.1.6 INSTRUCTION CACHE DATA READ/WRITE (ICHD_RWB). This output signal
indicates the direction of the data transfer to the cache data RAM. A high level indicates a
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Signal Summary
read cycle and a low level indicates a write cycle. It should be connected to the read/write
(RWB) signal of the compiled cache data RAM.
2.4.1.7 INSTRUCTION CACHE SIZE (ICH_SZ[2:0]). These static inputs specify the size
of the compiled cache RAMs connected to the ColdFire2/2M processor. Table 2-7 lists the
possible cache configurations. ICH_SZ[2:0] does not affect the CACR in any way; thus a
MOVEC instruction will write the CACR regardless of the ICH_SZ specification (which is
contrary to the SRAM_SZ and ROM_SZ effect during RAMBAR and ROMBAR loading).
Table 2-7. Cache Configuration Encoding
TAG RAM (BITS)
DATA RAM (BITS)
CACHE SIZE
(BYTES)
ICH_SZ[2:0]
ADDRESS
DATA
ADDRESS
DATA
None
512
000
001
010
011
100
101
110
111
-
5
-
-
-
24
23
22
21
20
19
18
7
32
32
32
32
32
32
32
1 K
6
8
2 K
7
9
4 K
8
10
11
12
13
8 K
9
16K†
32K†
10
11
NOTE: †16K and 32K RAMS may require a reduced operating frequency in HPF65
ColdFire2 Hard Macro.
2.4.1.8 INSTRUCTION CACHE TAG CHIP-SELECT (ICHT_CSB). This active-low output
signal indicates the cache tag RAM is currently selected to perform a data transfer with the
ColdFire2/2M. This signal should be connected to the chip-select (CSB) signal of the
compiled cache tag RAM.
2.4.1.9 INSTRUCTION CACHE TAG INPUT BUS (ICHT_DI[31:8]). These output signals
provide the write data path between the ColdFire2/2M and the cache tag RAM. The data bus
is 24-bits wide. Bit eight is always the valid bit and is always used as seen in the cache
configuration shown in Table 2-8. This bus should be connected to the data inputs (DBI) of
the compiled cache tag RAM. Functionally, ICH_ADDR[31:9] is what gets written onto
ICHT_DI[31:9] and ICHT_DI[8] is written with the valid state of the entry.
Table 2-8. Valid Tag RAM Data Signals
CACHE SIZE
VALID DATA BITS
(BYTES)
512
1 K
2 K
4 K
8 K
16K
32K
ICHT_Dx[31:8]
ICHT_Dx[31:10,8]
ICHT_Dx[31:11,8]
ICHT_Dx[31:12,8]
ICHT_Dx[31:13,8]
ICHT_Dx[31:14,8]
ICHT_Dx[31:15,8]
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Signal Summary
2.4.1.10 INSTRUCTION CACHE TAG OUTPUT BUS (ICHT_DO[31:8]). These input
signals provide the read data path between the cache tag RAM and the ColdFire2/2M. The
data bus is 24-bits wide. Bit eight is always the valid bit and is always used regardless of the
cache configuration as shown in Table 2-8. This bus should be connected to the data
outputs (DBO) of the compiled cache tag RAM. Unused signals must be tied low.
2.4.1.11 INSTRUCTION CACHE TAG STROBE (ICHT_ST). This output signal initiates a
read or write cycle to the cache tag RAM on a low-to-high transition. This signal should be
connected to the strobe input (ST) signal of the compiled cache tag RAM.
2.4.1.12 INSTRUCTION CACHE TAG READ/WRITE (ICHT_RWB). This output signal
indicates the direction of the data transfer to the cache tag RAM. A high level indicates a
read cycle and a low level indicates a write cycle. It should be connected to the read/write
(RWB) signal of the compiled cache tag RAM.
2.4.2 Integrated ROM Signals
These signals interface the ColdFire2/2M to the optional integrated ROMs.
2.4.2.1 ROM ADDRESS BUS (ROM_ADDR[14:2]). These output signals provide the
address of the current bus cycle to the integrated ROMs. This bus should be connected to
the address bus (A) of the compiled ROMs. The number of valid address signals depends
on the total ROM size as shown in Table 2-9.
Table 2-9. Valid ROM Address Bits
TOTAL ROM SIZE
VALID ROM_ADDR BITS
None
0
512
1 K
2 K
4 K
8 K
16K
32K
ROM_ADDR[8:2]
ROM_ADDR[9:2]
ROM_ADDR[10:2]
ROM_ADDR[11:2]
ROM_ADDR[12:2]
ROM_ADDR[13:2]
ROM_ADDR[14:2]
2.4.2.2 ROM DATA OUTPUT BUS (ROM_DO[31:0]). These input signals provide the
read data path from the integrated ROMs to the ColdFire2/2M. The data bus is 32-bits wide
and can transfer 8, 16, or 32 bits of data per bus transfer. During a line transfer, the data
lines are time-multiplexed across multiple cycles to carry 128 bits. This bus should be
connected to the data outputs (DO) of the compiled ROMs.
2.4.2.3 ROM ENABLE (ROM_ENB[1:0]). These active-low, output signals indicate the
ROMs are currently selected to drive the ROM_DO[31:0] bus. These signals should be
connected individually to the enable signal (ROMENB) signal of the compiled ROMs. Both
are asserted for 32-bit accesses. ROM_ENB[0] connects to the MSW while ROM_ENB[1]
connects to the LSW.
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Signal Summary
2.4.2.4 ROM SIZE (ROM_SZ[2:0]). These static inputs specify the size of the compiled
ROMs connected to the ColdFire2/2M. These pins need to stay valid during all operation.
Table 2-10 lists the possible ROM configurations. If the ROM_SZ pins are zero, the ROM
cannot be enabled via a CPU space write to ROMBAR. Therefore if the ROM is enabled
while the ROM_SZ pins are at zero, the processor behaves as if no ROM module existed.
Table 2-10. ROM Configuration Encoding
1
TOTAL ROM SIZE
ADDRESS
DATA
(BITS)
-
ROM_SZ[2:0]
(BYTES)
None
512
(BITS)
000
001
010
011
100
101
110
-
7
2 @ 16
2 @ 16
2 @ 16
2 @ 16
2 @ 16
2 @ 16
1 K
8
2 K
9
4 K
10
11
12
8 K
2
16K
2
111
13
2 @ 16
32K
NOTES: 1. 2 ROMs, each 16-bits wide
2. 16K and 32K ROMs may require a reduced operating frequency.
2.4.2.5 ROM VALID (ROM_VLD). This active-high input signal determines if the ROM
module should be active immediately after a hard reset. Thus, if asserted, the first fetches
($0, $4) go to ROM instead of external memory. ROM_VLD controls the reset value of the
ROM base address register (i.e. the ROM must be based at $0000 if ROM_VLD is
asserted).
2.4.3 Integrated SRAM Signals
These signals interface the ColdFire2/2M to the optional integrated SRAMs.
2.4.3.1 SRAM ADDRESS BUS (SRAM_ADDR[14:2]).
These registered output signals provide the address of the current bus cycle to the
integrated SRAMs. This bus should be connected to the address bus (A) of the four
compiled SRAMs. The number of valid address signals depends on the total SRAM size as
shown in Table 2-11.
Table 2-11. Valid SRAM Address Bits
TOTAL SRAM SIZE
VALID SRAM_ADDR BITS
None
0
512
1 K
2 K
4 K
8 K
16K
32K
SRAM_ADDR[8:2]
SRAM_ADDR[9:2]
SRAM_ADDR[10:2]
SRAM_ADDR[11:2]
SRAM_ADDR[12:2]
SRAM_ADDR[13:2]
SRAM_ADDR[14:2]
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2.4.3.2 SRAM CHIP-SELECT (SRAM_CSB). This active-low output signal indicates the
SRAMs are currently selected to perform a data transfer with the ColdFire2/2M. This signal
should be connected to the chip-select (CSB) signal of the four compiled SRAMs.
2.4.3.3 SRAM DATA INPUT BUS (SRAM_DI[31:0]). These output signals provide the
write data path between the ColdFire2/2M and the integrated SRAM. The data bus is 32-bits
wide and can transfer 8, 16, or 32 bits of data per bus transfer. During a line transfer, the
data lines are time-multiplexed across multiple cycles to carry 128 bits. This bus should be
connected to the data inputs (DBI) of the four compiled SRAMs. If only one byte is being
written, the byte will be replicated on all 4 lines likewise a word will be replicated in both word
positions.
2.4.3.4 SRAM DATA OUTPUT BUS (SRAM_DO[31:0]). These input signals provide the
read data path between the integrated RAM and the ColdFire2/2M. The data bus is 32-bits
wide and can transfer 8, 16 or 32 bits of data per bus transfer. During a line transfer, the data
lines are time-multiplexed across multiple cycles to carry 128 bits. This bus should be
connected to the data outputs (DBO) of the four compiled SRAMs.
2.4.3.5 SRAM SIZE (SRAM_SZ[2:0]). These static inputs specify the size of the compiled
SRAMs connected to the ColdFire2/2M. These pins need to stay valid during all operation.
If the SRAM_SZ pins are zero, the SRAM cannot be enabled via a CPU space write to
RAMBAR. Therefore if the RAM is enabled while the SRAM_SZ pins are at zero, the
processor behaves as if no SRAM module existed.
Table 2-12 lists the possible SRAM configurations.
Table 2-12. SRAM Configuration Encoding
1
TOTAL SRAM SIZE
ADDRESS
DATA
(BITS)
-
RAM_SZ[2:0]
(BYTES)
None
512
(BITS)
000
001
010
011
100
101
110
-
7
4@8
4@8
4@8
4@8
4@8
4@8
1 K
8
2 K
9
4 K
10
11
12
8 K
2
16K
2
111
13
4@8
32K
NOTES: 1. 4 RAMs, each 8-bits wide
2. 16K and 32K RAMs may require a reduced operating
frequency.
2.4.3.6 SRAM STROBE (SRAM_ST[3:0]). These output signals initiate a read or write
cycle to the integrated SRAMs on a low-to-high transition. These signals should be
connected individually to the strobe input (ST) signals of the four compiled SRAMs. The
ST[0] signal connects to the high-order byte and ST[3] connects to the low-order byte.
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2.4.3.7 SRAM READ/WRITE (SRAM_RWB[3:0]). These output signals indicate the
direction of the data transfer to the to the integrated SRAMs. A high level indicates a read
cycle and a low level indicates a write cycle. They should be connected individually to the
read/write (RWB) signal of the four compiled SRAMs. Like SRAM_ST[3:0], the
SRAM_RWB[3] signal connects to the high-order byte and SRAM_ST[0] connects to the
low-order byte.
2.5 DEBUG SIGNALS
2.5.1 Break Point (BKPTB)
This active-low, unidirectional input signal is used to request a manual break point. It will
cause the processor to enter a halted state after the completion of the current instruction.
This status will be reflected on the processor status (PST) outputs.
2.5.2 Debug Data (DDATA[3:0])
These output signals display the captured processor status and break point status.
2.5.3 Development Serial Clock (DSCLK)
This input signal is used as the development serial clock for the serial interface to the Debug
Module.The maximum frequency is 1/2 the clock (CLK) frequency.
2.5.4 Development Serial Input (DSI)
This input signal provides the single-bit communication for the Debug Module commands.
2.5.5 Development Serial Output (DSO)
This output signal provides single-bit communication for the Debug Module responses.
2.5.6 Processor Status (PST[3:0])
These output signals report the processor status. Table 2-13 shows the encoding of these
signals. These signals indicate the current status of the processor pipeline and, as a result,
are not related to the current bus transfer.
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Signal Summary
.
Table 2-13. Processor Status Encoding
PST[3:0]
(HEX) (BINARY)
DEFINITION
$0
$1
$2
$3
$4
$5
$6
$7
$8
$9
$A
$B
$C
$D
$E
$F
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Continue execution
Begin execution of an instruction
Reserved
Entry into user-mode
Begin execution of PULSE and WDDATA instructions
Begin execution of taken branch
Reserved
Begin execution of RTE instruction
Begin 1-byte transfer on DDATA
Begin 2-byte transfer on DDATA
Begin 3-byte transfer on DDATA
Begin 4-byte transfer on DDATA
Exception processing†
Emulator-mode entry exception processing†
Processor is stopped, waiting for interrupt†
Processor is halted †
NOTE: †These encodings are asserted for multiple cycles.
2.6 TEST SIGNALS
2.6.1 SIGNALS REQUIRED TO PERFORM SCAN TEST
This section describes the ColdFire2/2M signals dedicated to the scan testing of the
ColdFire2/2M. All ColdFire2/2M signals are unidirectional and synchronous.
2.6.1.1 SCAN ENABLE (SCAN_ENABLE). This active-high input signal enables scan
testing of the ColdFire2/2M. It forces all internal flip-flops to be linked together into sixteen
parallel scan chains. This signal must be negated for functional operation.
2.6.1.2 SCAN EXERCISE ARRAY (SCAN_XARRAY). This active-high input signal is
used to exercise the integrated memory arrays during scan testing. This signal causes
random writes to the internal RAMs by strobing the write strobes while scanning.
2.6.1.3 SCAN INPUT (SI[15:0]). These input signals are connected to the16 internal
ColdFire2/2M scan chain inputs.
2.6.1.4 SCAN MODE (SCAN_MODE). This active-high, unidirection input signal gates off
all memory array outputs during scan testing.SCAN_MODE should be held asserted for the
duration of scan testing.
2.6.1.5 SCAN OUTPUT (SO[15:0]). These output signals are connected to the 16 internal
ColdFire2/2M scan chain outputs.
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2.6.1.6 IO TEST RING CLOCK (TRCLK). This input signal is the synchronous clock used
to transition the test ring during scan testing. TR_CLK is connected to the clock input of all
IO test ring registers.
2.6.1.7 IO TEST RING CORE MODE ENABLE (CORE_TEST). This active-high input
signal enables the core mode of the test ring during scan testing. The test ring is in scan
core mode if CORE_TEST is asserted and in scan ASIC mode if CORE_TEST is negated.
2.6.1.8 IO TEST RING DATA INPUT (TR_SDI[1:0]). These input signals are the serial
data inputs for test ring chain one and zero.
2.6.1.9 IO TEST RING DATA OUTPUT (TR_SDO[1:0]). These output signals are the
serial output data from test ring chain one and zero.
2.6.1.10 IO TEST RING ENABLE (TR_SE). This active-high input signal enables the test
ring. TR_SE is connected to the scan enable input of all IO test ring scannable registers.
2.6.1.11 IO TEST RING MODE (TR_MODE). This active-high input signal enables the
scan test mode of the test ring. The test ring is in scan test mode if TR_MODE is asserted
and in normal functional mode if negated. TR_MODE should be asserted for the duration of
scan testing, and be held negated for the duration of memory testing and during functional
operation of the device.
2.6.2 Integrated Memory Test Signals
This section describes the ColdFire2/2M signals dedicated to testing the integrated
memories. Other signals are required to be either controlled or brought out (muxed) to
package pins as well (See Section 8 Test Operation).
2.6.2.1 TEST ADDRESS BUS (TEST_ADDR[14:2]). These input signals specify an
address when testing the integrated memories.
2.6.2.2 TEST CONTROL (TEST_CTRL). This active-high input signal indicates the test
address bus (TEST_ADDR[14:2]) will be latched on the next positive clock edge.
2.6.2.3 TEST IDATA READ (TEST_IDATA_RD). This active-high input signal tests the
instruction cache data memory read operation.
2.6.2.4 TEST IDATA WRITE (TEST_IDATA_WRT). This active-high input signal tests the
instruction cache data memory write operation.
2.6.2.5 TEST INSTRUCTION CACHE READ HIT (TEST_RHIT). This active-high output
signal indicates a hit has occurred when accessing the instruction cache during memory
array testing.
2.6.2.6 TEST INVALIDATE INHIBIT (TEST_IVLD_INH). This active-high input signal
inhibits the invalidate operation when testing the instruction cache.
2.6.2.7 TEST ITAG WRITE (TEST_ITAG_WRT). This active-high input signal tests the
instruction cache tag memory write operation.
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Signal Summary
2.6.2.8 TEST KTA MODE ENABLE (TEST_KTA). This active-high input signal allows the
instruction cache tag and data arrays to be read in parallel, mimicking the functional
operation. This allows testing of the speed path from the tag and data arrays to the core.
2.6.2.9 TEST MODE ENABLE (TEST_MODE). This active-high input signal enables all of
the integrated memory test signals. TEST_MODE should be asserted for the duration of
memory testing.
2.6.2.10 TEST SRAM READ (TEST_SRAM_RD). This active-high input signal tests the
integrated SRAM memory read operation.
2.6.2.11 TEST SRAM WRITE (TEST_SRAM_WRT). This active-high input signal tests the
integrated SRAM memory write operation.
2.6.2.12 TEST READ (TEST_RD). This active-high input signal tests read operations on all
of the integrated memories.
2.6.2.13 TEST ROM READ (TEST_ROM_RD). This active-high input signal tests the
integrated ROM memory read operation.
2.6.2.14 TEST WRITE INHIBIT (TEST_WR_INH). This active-high input signal disables
the write strobes to the SRAM and instruction cache compiled RAMS. TEST_WR_INH
should be negated for the duration of memory test.
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SECTION 3
MASTER BUS OPERATION
The master bus provides a basic two cycle bus protocol, similar to that used by previous
generations of M68000 microprocessors. Basic cycles are defined as the transfer start (TS)
cycle and the transfer acknowledge (TA) cycle. The address and control information is
driven onto the bus during the TS cycle, and the data is valid during the subsequent TA
cycle. By delaying the assertion of the transfer acknowledge signal, the bus automatically
inserts wait states to easily accommodate any slave response speed. The following sections
detail the signal descriptions, data transfer mechanism, and bus transfer protocols.
3.1 SIGNAL DESCRIPTION
This section describes the ColdFire2/2M signals associated with the master bus. All
ColdFire2/2M signals are unidirectional and synchronous.
3.1.1 68K Interrupt Acknowledge Mode Enable (IACK_68K)
This active-high input signal enables the 68K interrupt acknowledge mode. In this mode, the
MADDR[31:0], MTT[1:0], and MTM[2:0] signals mimic the 68K address bus and function
codes during interrupt acknowledge and CPU space bus cycles. This is a static input. Refer
to Section 3.7.1 Interrupt Acknowledge Bus Cycle for more information.
3.1.2 Master Address Bus (MADDR[31:0])
During a normal bus cycle, this 32-bit output bus provides the address of the first item of a
bus transfer. It is capable of addressing four Gbytes of address space.
3.1.3 Master Arbiter Control (MARBC[1:0])
These output signals can be used to specify the mode of operation for an optional arbitration
module. They reflect the bit positions [17:16] in the CACR. If an optional arbitration module
is not used, these signals can be used as general purpose output signals.
3.1.4 Master Freeze (MFRZB)
This active-low output signal indicates that the core has been halted. MFRZB is not part of
the M-Bus protocol. It is simply a signal that can be used to alert timers or other peripheral
modules that the core has been halted.
3.1.5 Master Kill (MKILLB)
This active-low output signal qualifies MTSB (i.e. it can assert in other cycles but is only
significant in a cycle where MSTB is asserted). When MKILLB is asserted simultaneously
with MTSB assertion, this indicates a hit in a K-Bus memory and that the external cycle must
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Master Bus Operation
be inhibited. This means the current master bus transaction is no longer required and should
be ignored (MTAB should not be asserted). MKILLB is asserted late in the MTSB cycle. Note
that if there is no K-Bus resident memory (ICACHE, SRAM, or ROM), MKILLB never
asserts. See Table 3-1 for MTSB/MKILLB interaction in table format.
Table 3-1. M-Bus Protocol with respect to MTSB and MKILLB
MTSB
MKILLB
M-BUS PROTOCOL
0
0
1
1
0
X
Initiate M-Bus transfer
Nop
Nop
3.1.6 Master Read Data Bus (MRDATA[31:0])
These input signals provide the read data path between the system and the ColdFire2/2M
device. The read data bus is 32-bits wide and can transfer 8, 16 or 32 bits of data per bus
transfer. During a line transfer, the data bus is time-multiplexed across multiple clock cycles
to transfer 128 bits.
3.1.7 Master Read Data Input Enable (MIE)
This active-high input signal enables the capturing of MRDATA[31:0]. Power consumption
can be reduced by minimizing signal switching in the ColdFire2/2M by negating MIE when
MRDATA[31:0] is invalid. MIE must be asserted during all one-master functional operation
and during K-Bus memory testing.
3.1.8 Master Read/Write (MRWB)
This output signal indicates the direction of the data transfer for the current bus cycle. A high
level indicates a read cycle and a low level indicates a write cycle.
3.1.9 Master Reset (MRSTB)
This active-low input signal instructs all master bus modules, including the ColdFire2/2M
device, to enter reset mode. The ColdFire2/2M processor will then initiate a reset exception.
3.1.10 Master Size (MSIZ[1:0])
These output signals indicate the data size for the bus transfer. Refer to Table 3-2 for the
bus size encoding.
Table 3-2. Master Bus Transfer Size Encoding
MSIZ[1:0]
TRANSFER SIZE
Longword (4 bytes)
Byte (1 byte)
00
01
10
11
Word (2 bytes)
Line (16 bytes)
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3.1.11 Master Transfer Acknowledge (MTAB)
This active low input signal is asserted by master bus slaves to indicate the successful
completion of a requested bus transfer.
3.1.12 Master Transfer Error Acknowledge (MTEAB)
This active low input signal is asserted by master bus slaves to indicate an error condition
for the current bus transfer. If MTAB and MTEAB are both asserted, the cycle is terminated
with an error because MTEAB always has precedence over MTAB.
3.1.13 Master Transfer Modifier (MTM[2:0])
These output signals provide supplemental information for each transfer type. The exact
meaning depends on the MTT[1:0], and IACK_68K signals as shown in Table 3-3.
Table 3-3. Master Bus Transfer Modifier Encoding
1
2
MTM[2:0] MTT[1:0]
COLDFIRE IACK MODE
Reserved
68K IACK MODE
000
001
0x
0x
0x
0x
0x
0x
0x
10
10
10
10
11
11
11
11
11
11
11
11
Reserved
User Data Access
User Code Access
Reserved
User Data Access
User Code Access
Reserved
010
011 - 100
101
Supervisor Data Access
Supervisor Data Access
Supervisor Code Access
Interrupt Acknowledge/CPU Space Access
Reserved
110
Supervisor Code Access
Reserved
111
000 - 100
101
Reserved
Emulator Mode Data Access
Emulator Mode Code Access
Reserved
Emulator Mode Data Access
Emulator Mode Code Access
Reserved
110
111
000
CPU Space Access
Reserved
001
Interrupt Acknowledge Level 1
Interrupt Acknowledge Level 2
Interrupt Acknowledge Level 3
Interrupt Acknowledge Level 4
Interrupt Acknowledge Level 5
Interrupt Acknowledge Level 6
Interrupt Acknowledge Level 7
Reserved
010
Reserved
011
Reserved
100
Reserved
101
Reserved
110
Reserved
111
Reserved
NOTES: 1. 68K interrupt acknowledge mode signal negated (IACK_68K = 0)
2. 68K interrupt acknowledge mode signal asserted (IACK_68K = 1)
3.1.14 Master Transfer Start (MTSB)
This active low output signal indicates the start of each bus transfer.
3.1.15 Master Transfer Type (MTT[1:0])
These output signals indicate the type of access of the current bus cycle. The exact meaning
depends on the IACK_68K signal as shown in Table 3-4.
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Table 3-4. Master Bus Transfer Type Encoding
1
2
MTT[1:0]
COLDFIRE IACK MODE
ColdFire2/2M Access
Alternate Master Access
Emulator Mode Access
68K IACK MODE
00
01
10
Acknowledge/CPU Space/ColdFire2/2M Access
Alternate Master Access
Emulator Mode Access
11
Acknowledge/CPU Space Access
Reserved
NOTES: 1. 68K interrupt acknowledge mode signal negated (IACK_68K = 0)
2. 68K interrupt acknowledge mode signal asserted (IACK_68K = 1)
3.1.16 Master Write Data Bus (MWDATA[31:0])
These output signals provide the write data path between the ColdFire2/2M and the system.
The write data bus is 32-bits wide and can transfer 8, 16 or 32 bits of data per bus transfer.
During a line transfer, the data bus is time-multiplexed across multiple clock cycles to carry
128 bits.
3.1.17 Master Write Data Output Enable (MWDATAOE)
This active high output signal indicates that the ColdFire2/2M is driving the master write data
bus. This is used to control optional bidirectional data bus three-state drivers.
3.2 DATA TRANSFER MECHANISM
3.2.1 Transfer Type Control Signals
The transfer type control signals indicate the type of bus transaction occurring on the master
bus. This includes the master transfer type (MTT[1:0]) and master transfer modifier
(MTM[2:0]) signals. The MTT[1:0] signals indicates the type of transfer and the MTM[2:0]
signals provide supplemental information. The encodings for MTT[1:0] and MTM[2:0] are
shown in Table 3-3 and Table 3-4. The transfer type attributes for accesses made through
the debug module are determined by the programming of the debug module (see Section
7.4.2.2 Address Attribute Register (AATR)).
3.2.1.1 COLDFIRE2/2M ACCESS. If the ColdFire2/2M requests a master bus transfer, it
drives the MTT[1:0] signals with a ColdFire2/2M access encoding. The MTM[2:0] encoding
will depend on the privilege mode and address space of the transfer:
Privilege Mode—Supervisor/User Mode Access
When the supervisor (S) bit in the status register (SR) is set, the ColdFire2/2M will drive
MTM[2:0] with one of the supervisor mode encodings during a master bus transfer. When
the S bit in the SR is clear, the ColdFire2/2M will drive MTM[2:0] with one of the user mode
access encodings.
Address Space—Code/Data Access
If the ColdFire2/2M accesses the code space, it will drive MTM[2:0] with one of the code
access encodings during a master bus transfer. Code space accesses are opcode fetches
or operand fetches in one of the PC relative addressing modes. If the ColdFire2/2M
accesses the data space, it will drive MTM[2:0] with one of the data access encodings. Data
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Master Bus Operation
space accesses are operand fetches that are not in one of the PC relative addressing
modes.
3.2.1.2 ALTERNATE MASTER ACCESS. When an alternate master requests a master
bus transfer, the MTT[1:0] signals should be driven with the alternate master access
encoding by the alternate master. The MTM[2:0] encoding is the same as that for the
ColdFire2/2M access.
3.2.1.3 EMULATOR MODE ACCESS. Accesses made while in emulator mode generate
emulator mode accesses on the master bus. This is controlled by the configuration/status
register (CSR) in the Debug module. Refer to Section 7.4.1.1 Emulator Mode.
Emulator mode accesses result in he MTT[1:0] signals being driven with the emulator mode
access encoding. The encoding of the MTM[2:0] signals will be one of the emulator mode
encodings depending on the address space as defined for the ColdFire2/2M access.
3.2.1.4 INTERRUPT ACKNOWLEDGE ACCESS. Interrupt acknowledge bus cycles are
indicated as an acknowledge/CPU space access on the MTT[1:0] signals (the encoding
depends on the interrupt acknowledge mode). If the ColdFire2/2M is in the ColdFire interrupt
acknowledge mode, the MTM[2:0] signals are driven with the pending interrupt level
number. In the 68K interrupt acknowledge mode, the MTM[2:0] signals will be driven high.
Refer to Section 3.7 Interrupt Acknowledge Bus Cycles.
3.2.1.5 CPU SPACE ACCESS. CPU space accesses are indicated as a acknowledge/
CPU space access on the MTT[1:0] signals. The MTM[2:0] signals are driven with a CPU
space encoding. The specific encoding depends on the interrupt acknowledge mode. Many
debug commands and MOVEC instructions result in CPU space accesses.
3.2.2 Data Bus Requirements
The ColdFire2/2M designates all operands for transfers on a byte-boundary system. A line-
sized operand (16 bytes) is four longwords. For all data transfers, MADDR[31:2] indicates
the longword base address of the first byte of the reference item. MADDR[1:0] indicates the
byte offset from this base address. The MSIZ[1:0] signals along with the low-order two
address signals are used to determine how the data bus is used. Table 3-5 indicates the
MRDATA[31:0] requirements for slave devices when responding to read transfers. A “-”
indicates a “don’t care”, i.e. the value is ignored.
Table 3-5. MRDATA Requirements for Read Transfers
TRANSFER SIZE MSIZ[1:0] MADDR[1:0] MRDATA[31:24] MRDATA[23:16] MRDATA[15:8] MRDATA[7:0]
Byte
01
01
01
01
10
10
00
11
00
01
10
11
00
10
00
00
Byte Data
-
-
-
-
-
-
Byte Data
-
-
-
-
Byte Data
-
-
Byte Data
Word
Word Data
-
-
Word Data
Long
Line
Longword Data
First Longword Data
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Master Bus Operation
Some of the system bus controllers (SBC) within the ColdFire architecture support
dynamically-sized external data transfers, i.e., the slave indicates the width of the data port
at the time of the transfer. To support this bus sizing feature, there are certain data
replication functions which must be performed by all master devices, including the
ColdFire2/2M, during write cycles. Table 3-6 indicates the MWDATA[31:0] requirements for
master devices when initiating write transfers.
Table 3-6. MWDATA Bus Requirements for Write Transfers
TRANSFER SIZE MSIZ[1:0] MADDR[1:0] MWDATA[31:24] MWDATA[23:16] MWDATA[15:8] MWDATA[7:0]
Byte
Word
Long
Line
01
10
00
11
--
Byte Data
Byte Data
Byte Data
Byte Data
-0
Word Data
Word Data
00
00
Longword Data
First Longword Data
Note that the ColdFire2/2M device, as well as all masters, places the byte operand on all
byte lanes for a byte write cycle, and the word operand on both word lanes for a word write
cycle.
3.3 DATA TRANSFERS
3.3.1 Byte, Word, and Longword Read Transfers
For byte, word, and longword read accesses, the ColdFire2/2M requests data from a slave
device. The bus operations are similar for the different sized accesses, with the MSIZ[1:0]
signals defining the access size. Based on the transfer size, the data is placed on the
appropriate byte lanes of the read data bus (MRDATA[31:0]). This read transfer is defined
in Figure 3-1.
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Master Bus Operation
MASTER
SLAVE
1) DRIVE ADDRESS ON MADDR[31:0]
2) SET MRWB TO READ (MRWB = 1)
3) SET MSIZ[1:0] TO BYTE, WORD, OR LONG
4) SET MTT[1:0], MTM[2:0] TO SIGNAL THE
APPROPRIATE ACCESS TYPE
1) DECODE THE ADDRESS AND SELECT
THE APPROPRIATE SLAVE DEVICE.
INSERT NECESSARY WAIT-STATES.
5) ASSERT MTSB FOR ONE CLK CYCLE
1) DRIVE THE DATA ON THE APPROPRIATE
BYTE LANES OF THE MRDATA[31:0] BUS,
BASED ON MSIZ[1:0], MADDR1:0].
2) ASSERT MIE FOR ONE CLK CYCLE.
2) ASSERT MTAB FOR ONE CLK CYCLE.
1) REGISTER THE MRDATA[31:0] BUS
2) RECOGNIZE THE TRANSFER IS DONE
Figure 3-1. Byte, Word, and Longword Read Transfer Flowchart
See Figure 3-2 for an example of normal read and write master bus transfers without wait
states.
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Master Bus Operation
C1
A1
C2
C1
A2
C2
CLK
MADDR
MRWB
MSIZ
MTT
MTM
MTSB
MWDATA
MWDATAOE
MRDATA
MIE
D2
D1
MTAB
MTEAB
READ
WRITE
Figure 3-2. Normal Transfer (without Wait States)
Clock 1 (C1)
The read cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid values
on the master address bus (MADDR[31:0]) and transfer control signals. The MTT[1:0] and
MTM[2:0] signals identify the specific access type. The master read/write (MRWB) signal is
driven high for a read cycle, and the master size signals (MSIZ[1:0]) indicate transfer size.
The ColdFire2/2M asserts the master transfer start (MTSB) signal during C1 to indicate the
beginning of a bus cycle.
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB. The selected device uses the
MRWB and MSIZ signals to place the data on the master read data bus (MRDATA[31:0])
and assert the master input enable (MIE) signal. Concurrently, the selected device asserts
the master transfer acknowledge (MTAB) signal. At the end of C2, the ColdFire2/2M
samples the level of MTAB and latches the current value on MRDATA[31:0]. If MTAB is
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Master Bus Operation
asserted, the transfer terminates. If MTAB is not asserted, the ColdFire2/2M processor
ignores the data and inserts wait states instead of terminating the transfer. The ColdFire2/
2M continues to sample MTAB on successive rising edges of CLK until it is asserted. The
selected device negates the MIE and MTAB signals in the first half of the next CLK cycle.
3.3.2 Normal Tranfers with MKILLB
Figure3-3 illustrates normal tranfers (no wait states) with MKILLB asserted and negated:
C1
C2
C3
C4
C7
C5
C6
CLK
MADDR
MRWB
MSIZ
MTT
MTM
MTSB
MKILLB
MWDATA
WDATA
MRDATA
MIE
MTAB
MTEAB
Internal
External
Read
External
Write
Internal
Integ.
Memory
Write
Next
Access
Integ.
Memory
Read
Figure 3-3. Normal Transfer with MKILLB Timing Diagram (without wait states)
Clock 1 (C1)
The read cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid values
on the master address bus (MADDR[31:0]) and transfer control signals. The MTT[1:0] and
MTM[2:0] signals identify the specific access type. The master read/write (MRWB) signal is
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Master Bus Operation
driven high for a read cycle, and the master size signals (MSIZ[1:0]) indicate transfer size.
The ColdFire2/2M asserts the master transfer start (MTSB) signal during C1 to indicate the
beginning of a bus cycle. MKILLB does not assert during this cycle so the access will go
external via M-Bus.
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M processor negates MTSB. The selected device
uses the MRWB and MSIZ signals to place the data on the master read data bus
(MRDATA[31:0]) and assert the master input enable (MIE) signal. Concurrently, the
selected device asserts the master transfer acknowledge (MTAB) signal. At the end of C2,
the ColdFire2/2M processor samples the level of MTAB and latches the current value on
MRDATA[31:0]. If MTAB is asserted, the transfer terminates. If MTAB is not asserted, the
ColdFire2/2M ignores the data and inserts wait states instead of terminating the transfer.
The ColdFire2/2M continues to sample MTAB on successive rising edges of CLK until it is
asserted. The selected device negates the MIE and MTAB signals in the first half of the next
CLK cycle.
Clock 3 (C3)
Another read cycle begins in C3; however this read cycle will be to internal integrated
memory. During the first half of C3, the ColdFire2/2M places valid values on the master
address bus (MADDR[31:0]) and transfer control signals. The MTT[1:0] and MTM[2:0]
signals identify the specific access type. The master read/write (MRWB) signal is driven high
for a read cycle, and the master size signals (MSIZ[1:0]) indicate transfer size. The
ColdFire2/2M asserts the master transfer start (MTSB) signal during C3 to indicate the
beginning of a bus cycle. MKILLB asserts late in the cycle. The combination of the assertion
of both (MTSB and MKILLB signifies that the access will occur internally in integrated
memory and the M-Bus transaction is not needed. The internal access will complete in one
cycle; therefore another access can begin immediately on the following cycle.
Clock 4 (C4)
A write cycle starts in C4. During the first half of C4, the ColdFire2/2M places valid values
on the master address bus (MADDR[31:0]) and transfer control signals. The MTT[1:0] and
MTM[2:0] signals identify the specific access type. The master read/write (MRWB) signal is
driven low for a write cycle, and the master size signals (MSIZ[1:0]) indicate transfer size.
The ColdFire2/2M asserts the master transfer start (MTSB) signal during C4 to indicate the
beginning of a bus cycle. MKILLB does not assert during this cycle so the access will go
external via M-Bus.
Cycle 5 (C5)
During the first half of C5, the ColdFire2/2M negates MTSB. The selected device uses the
MRWB and MSIZ signals to take the data off the master write data bus (MWDATA[31:0].
Concurrently, the selected device asserts the master transfer acknowledge (MTAB signal.
At the end of C5, if MTAB is asserted, the transfer terminates. If MTAB is not asserted, the
ColdFire2/2M inserts wait states instead of terminating the transfer. The ColdFire2/2M
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Master Bus Operation
continues to sample MTAB on successive rising edges of CLK until it is asserted. The
selected device negates the (MTAB signal in the first half of the next CLK cycle.
Cycle 6 (C6)
Another write cycle begins in C6; however this write cycle will be to internal integrated
memory. During the first half of C6, the ColdFire2/2M places valid values on the master
address bus (MADDR[31:0]) and transfer control signals. The MTT[1:0] and MTM[2:0]
signals identify the specific access type. The master read/write (MRWB) signal is driven low
for a write cycle, and the master size signals (MSIZ[1:0]) indicate transfer size. The
ColdFire2/2M asserts the master transfer start (MTSB) signal during C6 to indicate the
beginning of a bus cycle. MKILLB asserts late in the cycle. The combination of the assertion
of both (MTSB and MKILLB signifies that the access will occur internally in integrated
memory and the M-Bus transaction is not needed. The internal access will complete in one
cycle; therefore another access can begin immediately on the following cycle.
Cycle 7 (C7)
Another access can begin in this cycle ((MTSB can assert).
3.3.3 Byte, Word, and Longword Write Transfers
For byte, word, and longword write accesses, the ColdFire2/2M transfers data to a slave
device. The bus operations are similar for the different sized accesses, with the MSIZ[1:0]
signals defining the access size. Based on the transfer size, the data is placed on the
appropriate byte lanes of the write data bus (MWDATA[31:0]). This write transfer is defined
in Figure 3-4.
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Master Bus Operation
MASTER
SLAVE
1) DRIVE ADDRESS ON MADDR[31:0]
2) SET MRWB TO WRITE (MRWB = 0)
3) SET MSIZ[1:0] TO BYTE, WORD, OR LONG
4) SET MTT[1:0], MTM2:0] TO SIGNAL THE
APPROPRIATE ACCESS TYPE
5) ASSERT MTSB FOR ONE CLK CYCLE
1) DECODE THE ADDRESS AND SELECT
THE APPROPRIATE SLAVE DEVICE.
INSERT NECESSARY WAIT-STATES.
1) CAPTURE THE DATA FROM THE
APPROPRIATE BYTE LANES OF THE
MWDATA[31:0] BUS, BASED ON
MSIZ[1:0], MADDR[1:0]
1) DRIVE DATA ONTO MWDATA[31:0]
2) ASSERT MWDATAOE
2) ASSERT MTAB FOR ONE CLK CYCLE
1) RECOGNIZE THE TRANSFER IS DONE
2) NEGATE MWDATAOE
Figure 3-4. Byte, Word, and Longword Write Transfer Flowchart
See Figure 3-2 for an example of a normal write transfer without wait states. Figure 3-5
shows an example of a normal write master bus transfer with wait states. Note the Cxw
nomenclature is used to define a wait state during the bus cycle—e.g., C2w.
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C1
A1
C2W
C2W
C2
CLK
MADDR
MRWB
MSIZ
MTT
MTM
MTSB
MWDATA
MWDATAOE
MTAB
D1
MTEAB
WRITE
Figure 3-5. Normal Write Transfer (with Wait States)
Clock 1 (C1)
The write cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid values
on the master address bus (MADDR[31:0]) and transfer control signals. The master transfer
type (MTT[1:0]) and master transfer modifier (MTM[2:0]) signals identify the specific access
type. The master read/write (MRWB) signal is driven low for a write cycle, and the master
size signals (MSIZ[1:0]) indicate transfer size. The ColdFire2/2M asserts the master transfer
start (MTSB) signal during C1 to indicate the beginning of a bus cycle.
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB, places the data on the master
write data bus (MWDATA[31:0]), and asserts the master write data output enable
(MWDATAOE) signal. Concurrently, the selected device asserts the master transfer
acknowledge (MTAB) signal if it is ready to latch the data. At the end of C2, the selected
device latches the current value on MWDATA[31:0], and the ColdFire2/2M samples the
level of MTAB. If MTAB is asserted, the bus cycle is terminated and the ColdFire2/2M
negates MWDATAOE in the first half on the next CLK cycle. If MTAB is not asserted, the
ColdFire2/2M inserts wait states instead of terminating the transfer. The ColdFire2/2M
continues to sample MTAB on successive rising edges of CLK until it is asserted.
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Master Bus Operation
3.3.4 Line Read Transfer
The ColdFire2/2M uses a line read access to fetch a four-longword operand using a burst
transfer. A line read accesses a block of four longwords, aligned to a 16-byte memory
boundary, by supplying a starting address that points to the critical longword in the four-
longword block. The address and attributes driven by the ColdFire2/2M remain stable
throughout the entire transfer. As a result, the slave device must increment MADDR[3:2]
internally to sequence for each transfer with the address wrapping around at the end of the
block. The allowable longword fetch patterns during a line access are shown in Table 3-7.
Table 3-7. Allowable Line Access Patterns
MADDR[3:2]
LONGWORD ACCESS ORDER
0 - 4 - 8 - C
00
01
10
11
4 - 8 - C - 0
8 - C - 0 - 4
C - 0 - 4 - 8
The responding slave device terminates each longword transfer on the MRDATA[31:0] bus
by asserting the transfer acknowledge control signal, MTAB. All devices on the master bus
must support burst accesses. The assertion of MTEAB aborts the line read access. See
Section 3.8.1 Access Errors for more information on MTEAB.
A line read burst is defined in Figure 3-6.
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Master Bus Operation
MASTER
SLAVE
1) DRIVE ADDRESS ON MADDR[31:0]
2) SET MRWB TO READ (MRWB = 1)
3) SET MSIZ[1:0] TO LINE
4) SET MTT[1:0] AND MTM[2:0] TO SIGNAL THE
APPROPRIATE ACCESS TYPE
1) DECODE THE ADDRESS AND SELECT
THE APPROPRIATE SLAVE DEVICE.
INSERT NECESSARY WAIT-STATES.
5) ASSERT MTSB FOR ONE CLK CYCLE
1) DRIVE THE DATA ON MRDATA[31:0].
2) ASSERT MIE FOR ONE CLK CYCLE.
3) ASSERT MTAB FOR ONE CLK CYCLE.
1) REGISTER THE MRDATA[31:0] BUS
2) RECOGNIZE THE 1ST TRANSFER IS DONE
1) DRIVE THE DATA ON MRDATA[31:0].
2) ASSERT MIE FOR ONE CLK CYCLE.
3) ASSERT MTAB FOR ONE CLK CYCLE.
1) REGISTER THE MRDATA[31:0] BUS
2) RECOGNIZE THE 2ND TRANSFER IS DONE
1) DRIVE THE DATA ON MRDATA[31:0].
2) ASSERT MIE FOR ONE CLK CYCLE.
3) ASSERT MTAB FOR ONE CLK CYCLE.
1) REGISTER THE MRDATA[31:0] BUS
2) RECOGNIZE THE 3RD TRANSFER IS DONE
1) DRIVE THE DATA ON MRDATA[31:0].
2) ASSERT MIE FOR ONE CLK CYCLE.
3) ASSERT MTAB FOR ONE CLK CYCLE.
1) REGISTER THE MRDATA[31:0] BUS
2) RECOGNIZE THE 4TH TRANSFER IS DONE
Figure 3-6. Line Read Transfer Flowchart
See Figure 3-7 for an example of a line read burst master bus transfer without wait states.
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Master Bus Operation
C1
A1
C2
C3
C4
C5
CLK
MADDR
MRWB
MSIZ
$3
MTT
MTM
MTSB
MRDATA
MIE
D1
D2
D3
D4
MTAB
MTEAB
Figure 3-7. Line Read Transfer (without Wait States)
Clock 1 (C1)
The line read cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid
values on the master address bus (MADDR[31:0]) and transfer control signals. The master
transfer type (MTT[1:0]) and master transfer modifier (MTM[2:0]) signals identify the specific
access type. The master read/write (MRWB) signal is driven high for a read cycle, and the
master size signals (MSIZ[1:0]) indicate transfer size (Line = $3). The ColdFire2/2M asserts
the master transfer start (MTSB) signal during C1 to indicate the beginning of a bus cycle.
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB. The selected device uses the
MRWB and MSIZ signals to place the data on the master read data bus (MRDATA[31:0])
and assert the master input enable (MIE) signal. The first transfer must supply the longword
at the corresponding long-word boundary. Concurrently, the selected device asserts master
transfer acknowledge (MTAB) signal. At the end of C2, the ColdFire2/2M samples the level
of MTAB and latches the current value on MRDATA[31:0]. If MTAB is asserted, the transfer
of the first longword terminates. If MTAB is not asserted, the ColdFire2/2M ignores the data
and inserts wait states instead of terminating the transfer. The ColdFire2/2M continues to
sample MTAB on successive rising edges of CLK until it is asserted.
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Master Bus Operation
Clock 3 (C3)
The ColdFire2/2M holds the address and transfer control signals constant during C3. The
selected device must increment the MADDR[3:2] signals to reference the next longword to
transfer, place the data on MRDATA[31:0], assert MIE, and assert MTAB. At the end of C3,
the ColdFire2/2M samples the level of MTAB and latches the current value on the
MRDATA[31:0] signals. If MTAB is asserted, the transfer terminates. If MTAB is not asserted
at the end of C3, the ColdFire2/2M ignores the latched data and inserts wait states instead
of terminating the transfer. The ColdFire2/2M continues to sample MTAB on successive
rising edges of CLK until it is asserted.
Clock 4 (C4)
This clock is identical to C3 except that once MTAB is recognized as being asserted, the
latched value corresponds to the third longword of data for the burst.
Clock 5 (C5)
This clock is identical to C3 except that once MTAB is recognized, the latched value
corresponds to the fourth longword of data for the burst. This is the last clock cycle of the
line read transaction. The selected device negates the MIE and MTAB signals in the first half
of the next CLK cycle.
3.3.5 Line Write Transfers
The line write transfer is similar to the line read transfer. This 16-byte burst write transfer is
defined in Figure 3-8.
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Master Bus Operation
MASTER
SLAVE
1) DRIVE ADDRESS ON MADDR[31:0]
2) SET MRWB TO WRITE (MRWB = 0)
3) SET MSIZ[1:0] TO LINE
4) SET MTT[1:0] AND MTM[2:0] TO SIGNAL THE
APPROPRIATE ACCESS TYPE
1) DECODE THE ADDRESS AND SELECT
THE APPROPRIATE SLAVE DEVICE
5) ASSERT MTSB FOR ONE CLK CYCLE
2) INSERT NECESSARY WAIT-STATES
1) DRIVE DATA ONTO MWDATA[31:0]
2) ASSERT MWDATAOE
1) CAPTURE THE DATA FROM
MWDATA[31:0]
1) RECOGNIZE THE 1ST TRANSFER IS DONE
2) ASSERT MTAB FOR ONE CLK CYCLE
1) DRIVE DATA ONTO MWDATA[31:0]
1) CAPTURE THE DATA FROM
MWDATA[31:0]
2) ASSERT MTAB FOR ONE CLK CYCLE
1) RECOGNIZE THE 2ND TRANSFER IS DONE
1) DRIVE DATA ONTO MWDATA
[31:0]
1) CAPTURE THE DATA FROM
MWDATA[31:0]
2) ASSERT MTAB FOR ONE CLK CYCLE
2) RECOGNIZE THE 3RD TRANSFER IS DONE
1) DRIVE DATA ONTO MWDATA[31:0]
1) CAPTURE THE DATA FROM
MWDATA[31:0]
2) ASSERT MTAB FOR ONE CLK CYCLE
1) RECOGNIZE THE 4TH TRANSFER IS DONE
2) NEGATE MWDATAOE
Figure 3-8. Line Write Transfer Flowchart
The assertion of MTEAB will abort a line write transfer. See Section 3.8.1 Access Errors
for more information on MTEAB. It is the slave’s responsibility to increment and wrap the
MADDR[3:2] signals internally.
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Master Bus Operation
See Figure 3-9 for an example of a line write master bus transfer without wait states.
C1
A1
C2
C3
C4
C5
CLK
MADDR
MRWB
MSIZ
$3
MTT
MTM
MTSB
MWDATA
MWDATAOE
MTAB
D1
D2
D3
D4
MTEAB
Figure 3-9. Line Write Transfer (without Wait States)
Clock 1 (C1)
The line write cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid
values on the master address bus (MADDR[31:0]) and transfer control signals. The master
transfer type (MTT[1:0]) and master transfer modifier (MTM[2:0]) signals identify the specific
access type. The master read/write (MRWB) signal is driven low for a write cycle, and the
master size signals (MSIZ[1:0]) indicate line size ($3). The ColdFire2/2M asserts the master
transfer start (MTSB) signal during C1 to indicate the beginning of a bus cycle.
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB, places the first longword of data
on the master write data bus (MWDATA[31:0]), and asserts the master write data output
enable (MWDATAOE) signal. Concurrently, the selected device asserts the master transfer
acknowledge (MTAB) signal if it is ready to latch the data. At the end of C2, the ColdFire2/
2M samples the level of MTAB, and the selected device latches MWDATA[31:0]. If MTAB is
asserted, the transfer of the first longword terminates. If MTAB is not asserted, the
ColdFire2/2M inserts wait states instead of terminating the transfer. The ColdFire2/2M
continues to sample MTAB on successive rising edges of CLK until it is recognized asserted.
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Master Bus Operation
Clock 3 (C3)
The ColdFire2/2M holds the address and transfer control signals constant during C3, but
drives MWDATA[31:0] with the second longword of data. The selected device must
increment MADDR[3:2] to reference the second longword address, and assert MTAB. At the
end of C3, the ColdFire2/2M samples the level of MTAB, and the selected device latches
MWDATA[31:0]. If MTAB is asserted, the transfer terminates. If MTAB is not recognized
asserted at the end of C3, the ColdFire2/2M inserts wait states instead of terminating the
transfer. The ColdFire2/2M continues to sample MTAB on successive rising edges of CLK
until it is recognized.
Clock 4 (C4)
This clock is identical to C3 except that once MTAB is asserted, the value corresponds to
the third longword of data for the burst.
Clock 5 (C5)
This clock is identical to C3 except that once MTAB is asserted, the data value corresponds
to the fourth longword of data for the burst. This is the last clock cycle of the line write
transaction and the ColdFire2/2M negates MWDATAOE in the first half of the next CLK
cycle.
See Figure 3-10 for an example of a line write master bus transfer with wait states. Note the
Cxw nomenclature that is used to define a wait state during the bus cycle, e.g., C2w.
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Master Bus Operation
C1
A1
C2W
C2
C3W
C3
C4W
C4
C5W
C5
CLK
MADDR
MRWB
MSIZ
$3
MTT
MTM
MTSB
MWDATA
MWDATAOE
MTAB
D1
D2
D3
D4
MTEAB
Figure 3-10. Line Write Transfer (with Wait States)
3.4 MISALIGNED OPERANDS
All ColdFire2/2M data formats can be located in memory on any byte boundary. A byte
operand is properly aligned at any address, a word operand is misaligned at an odd address,
and a longword is misaligned at an address that is not evenly divisible by four. However,
since operands can reside at any byte boundary, they can be misaligned. Although the
ColdFire2/2M does not enforce any alignment restrictions for data operands, including PC
relative data addressing, some performance degradation occurs when additional bus cycles
are required for longword or word operands that are misaligned. For maximum performance,
data items should be aligned on their natural boundaries. All instruction words and extension
words must reside on word boundaries. Attempting to prefetch an instruction word at an odd
address causes an address error exception. See Section 4.2.3 Address Error Exception
for more information.
The ColdFire2/2M misalignment unit converts misaligned operand accesses that are
noncachable to a sequence of aligned accesses. Figure 3-11 illustrates the transfer of a
longword operand from an odd address requiring more than one bus cycle. In this example,
the MSIZ[1:0] signals specify a byte transfer, and the byte offset is $1. The slave device
supplies the byte and acknowledges the data transfer. When the ColdFire2/2M starts the
second cycle, the MSIZ[1:0] signals specify a word transfer with a byte offset of $2. The next
two bytes are transferred during this cycle. The ColdFire2/2M then initiates the third cycle,
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Master Bus Operation
with the MSIZ[1:0] signals indicating a byte transfer. The byte offset is now $0; the port
supplies the final byte and the operation is complete. This example is similar to the one
illustrated in Figure 3-12 except that the operand is word sized and the transfer requires only
two bus cycles. Figure 3-13 illustrates a functional timing diagram for a misaligned word read
transfer.
31
24 23
16 15
8 7
0
Transfer 1
Transfer 2
Transfer 3
-
-
Byte 3
-
Byte 2
-
-
Byte 1
-
-
-
Byte 0
Figure 3-11. Example of a Misaligned Longword Transfer
31
24 23
16 15
8 7
0
Transfer 1
Transfer 2
-
-
-
-
-
Byte1
-
Byte 0
Figure 3-12. Example of a Misaligned Word Transfer
C1
A1
C2
C1
A2
C2
CLK
MADDR
MRWB
MSIZ
$1
$1
MTT
MTM
MTSB
MRDATA
MIE
D1
D2
MTAB
MTEAB
READ 1
READ 2
Figure 3-13. Misaligned Word Read Transfer
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Master Bus Operation
The combination of operand size and alignment determines the number of bus cycles
required to perform a particular memory access. Table 3-8 lists the number of bus cycles
required for different operand sizes with all possible alignment conditions for read and write
cycles. The table confirms that alignment significantly affects bus cycle throughput for
noncachable accesses. For example, in Figure 3-11 the misaligned longword operand took
three bus cycles because the first byte offset = $1. If the byte offset = $0, then it would have
taken one bus cycle. The ColdFire2/2M system designer and programmer should account
for these effects, particularly in time-critical applications.
Table 3-8. Memory Alignment Cycles
TRANSFER SIZE
Instruction
$0†
1
$1†
-
$2†
-
$3†
-
Byte Operand
1
1
1
1
Word Operand
Longword Operand
1
2
1
2
1
3
2
3
NOTE: †Where the byte offset (MADDR[1:0]) equals this encoding.
3.5 INVALID MASTER BUS CYCLES
The ColdFire2/2M starts a master bus transaction before it determines if the address hits in
the cache or is mapped to the internal memories. As a result, the ColdFire2/2M will assert
the MKILLB signal (late in that MTSB cycle) to indicate the current bus transaction resulted
in a hit in the cache or internal memories. When this signal is asserted, master bus slaves
must stop driving the master bus and must not return a MTAB or MTEAB. The current
master bus cycle must be inhibited.
The general priority scheme is as follows:
if (SRAM “hits”)
SRAM supplies data to the processor
else if (ROM “hits”)
ROM supplies data to the processor
else if (line fill buffer “hits”)
line fill buffer supplies data to the processor
else if (icache “hits”)
icache supplies data to the processor
else
master bus cycle accesses to reference data from non-local memory
Clock 1 (C1)
The read cycle starts in C1. During the first half of C1, the ColdFire2/2M places valid values
on the master address bus (MADDR[31:0]) and transfer control signals. The ColdFire2/2M
asserts the master transfer start (MTSB) signal during C1 to indicate the beginning of a bus
cycle.
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Master Bus Operation
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB. Because the MKILLB signal
was not asserted during the rising clock edge of C2, the selected device uses the MRWB
and MSIZ signals to place the data on the master read data bus (MRDATA[31:0]) and assert
the master input enable (MIE) signal. Concurrently, the selected device asserts the master
transfer acknowledge (MTAB) signal. At the end of C2, the ColdFire2/2M samples the level
of MTAB and captures the current value on MRDATA[31:0]. If MTAB is asserted, the transfer
terminates. If MTAB is not asserted, the ColdFire2/2M ignores the data and inserts wait
states instead of terminating the transfer. The ColdFire2/2M continues to sample MTAB on
successive rising edges of CLK until it is asserted. The selected device negates the MIE and
MTAB signals in the first half of the next CLK cycle.
Clock 3 (C3)
The read cycle starts in C3. The ColdFire2/2M asserts the MTSB signal, and then the
MKILLB signal. This signifies that the M-Bus cycle must be inhibited; i.e. the access has “hit”
in an internal-bus memory.
Clock 4 (C4)
Nop.
Clock 5 (C5)
The read cycle starts in C5. The ColdFire2/2M asserts the MTSB signal, and then the
MKILLB signal. This signifies that the M-Bus cycle must be inhibited; i.e. the access has “hit”
in an internal K-Bus memory.
Clock 6 (C6)
Another read cycle starts in C6. The C1 description applies here.
Clock 7 (C7)
During the first half of C7, the ColdFire2/2M negates MTSB. Because the MKILLB signal
was not asserted during the rising clock edge of C7, the selected device uses the MRWB
and MSIZ signals to place the data on the master read data bus (MRDATA[31:0]). The rest
of the C2 description applies here.
3.6 PIPELINE STALLS
In an idealized environment for maximum performance, all ColdFire2/2M references are
mapped to integrated memory resources and complete in a single clock cycle. Any memory
reference that generates a master bus access stalls the processor pipeline since the internal
transfer cannot be completed in a single clock cycle. This performance degradation factor
can be expressed as:
Pipeline Stall = Master Bus Clock Cycles - 1
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Master Bus Operation
where the stall is measured in clock cycles, and Master Bus Clock Cycles represents the
entire master bus transfer time in clock cycles. In the examples shown in Figure 3-14, the
read cycle with one wait state stalls the ColdFire2/2M for two clock cycles, and the zero wait
state write transfer produces a stall of one clock cycle.
C1
A1
C2W
C2
C1
A2
C2
CLK
MADDR
MRWB
MSIZ
MTT
MTM
MTSB
MWDATA
MWDATAOE
MRDATA
MIE
D2
D1
MTAB
MTEAB
READ
WRITE
Figure 3-14. Example Master Bus Wait State
3.7 INTERRUPT ACKNOWLEDGE BUS CYCLES
When a peripheral device requires the services of the ColdFire2/2M or is ready to send
information that the ColdFire2/2M requires, it can signal the ColdFire2/2M to take an
interrupt exception. The interrupt exception transfers control to a routine that responds
appropriately. The peripheral device uses the active-low interrupt priority level signals
(IPLB[2:0]) to signal an interrupt condition to the ColdFire2/2M and to specify the priority
level for the condition. Refer to Section 4 Exception Processing for a discussion on the
IPLB[2:0] levels.
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Master Bus Operation
The status register of the ColdFire2/2M, described in Section 1.4.3.1 Status Register (SR),
contains an interrupt priority mask (IPLB[2:o]). The value in the interrupt mask is the highest
priority level that the ColdFire2/2M ignores. When an interrupt request has a priority higher
than the value in the mask, the ColdFire2/2M makes the request a pending interrupt.
IPLB[2:0] must maintain the interrupt request level until the ColdFire2/2M acknowledges the
interrupt to guarantee that the interrupt is recognized. The ColdFire2/2M continuously
samples IPLB[2:0] on consecutive rising edges of CLK. As a result, the IPLB[2:0] signals are
synchronous and must meet setup and hold times to CLK. If the external IPLB[2:0] signals
are asynchronous, flip-flops should be used to synchronize them before they drive the
IPLB[2:0] signals on the ColdFire2/2M.
The ColdFire2/2M takes an interrupt exception for a pending interrupt within one instruction
boundary after processing any other pending exception with a higher priority. Thus, the
ColdFire2/2M executes at least one instruction in an interrupt exception handler before
recognizing another interrupt request. The following paragraphs describe the two kinds of
interrupt acknowledge bus cycles that can be executed as part of interrupt exception
processing.
3.7.1 Interrupt Acknowledge Bus Cycle (Terminated Normally)
When the ColdFire2/2M processes an interrupt exception, it performs an interrupt
acknowledge bus cycle to obtain the vector number that contains the starting location of the
interrupt exception handler. Most interrupting devices have programmable vector registers
that contain the interrupt vectors for the exception handlers they use. Others may have fixed
vector numbers. The values driven on MADDR[31:0], MTT[1:0], and MTM[2:0] are
dependent on the interrupt acknowledge mode. The interrupt acknowledge mode is
statically determined by the connection of the 68K interrupt acknowledge mode enable
(IACK_68K) signal.
The interrupt acknowledge bus cycle is a read transfer. If the ColdFire2/2M is in the ColdFire
interrupt acknowledge mode (IACK_68K negated), it differs from a normal read cycle in the
following respects:
1. MTT[1:0]= $3 to indicate a acknowledge/CPU space bus cycle.
2. Address signals MADDR[31:5] are set to all ones ($3FFFFFF). The MADDR[4:2]
signals are set to the pending interrupt number, and the MADDR[1:0] signals are
driven low.
3. MTM[2:0] are set to the interrupt request level, the inverted values of IPLB[2:0]. This
will be nonzero for all interrupt acknowledge cycles.
If the ColdFire2/2M is in the 68K interrupt acknowledge mode (IACK_68K asserted), it differs
in the following respects:
1. MTT[1:0] = $0 to indicate a Acknowledge/CPU space bus cycle.
2. Address signals MADDR[31:4] are set to all ones ($7FFFFFF). The MADDR[3:1]
signals are set to the pending interrupt number, and the MADDR[0] signal is driven
high.
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Master Bus Operation
3. MTM[2:0] = $7 to indicate an interrupt acknowledge cycle.
The responding device places the vector number on MRDATA[31:24] during the interrupt
acknowledge bus cycle, and the cycle is terminated normally with MTAB. Figure 3-15
illustrates a flowchart diagram for an interrupt acknowledge cycle terminated with MTAB.
MASTER
SLAVE
REQUEST INTERRUPT ON IPLB[2:0]
1) RECOGNIZE PENDING INTERRUPT
2) WAIT FOR INSTRUCTION BOUNDARY
1) DRIVE APPROPRIATE VALUE ON
MADDR[31:0]
2) SET MRWB TO READ ($1)
3) SET MSIZ[1:0] TO BYTE ($1)
4) SET MTT[1:0] TO ACKNOWLEDGE
5) DRIVE VALUE ON MTM[2:0]
1) DECODE THE ADDRESS AND SELECT
THE INTERRUPTING SLAVE DEVICE.
6) ASSERT MTSB FOR ONE CLK CYCLE
2) INSERT NECESSARY WAIT-STATES.
3) REMOVE INTERRUPT ON IPLB[2:0]
1) DRIVE THE VECTOR NUMBER ON
MRDATA[31:24]
1) LATCH VECTOR NUMBER
2) ASSERT MTAB FOR ONE CLK CYCLE.
3) ASSERT MIE FOR ONE CLK CYCLE.
2) RECOGNIZE THE TRANSFER IS DONE
Figure 3-15. Interrupt Acknowledge Bus Cycle Flowchart
See Figure 3-16 for an example of a ColdFire mode (IACK_68K negated) interrupt
acknowledge cycle. The interrupt shown occurs during a normal master bus read cycle with
no lower-order interrupts pending.
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Master Bus Operation
C1
C2
CLK
IPLB
MADDR[31:5]
MADDR[4:2]
MADDR[1:0]
MRWB
STACK
STACK
STACK
INT LEVEL
MSIZ
$1
MTT
$0
$5
MTM
INT LEVEL
MTSB
MWDATA
MWDATAOE
MRDATA[31:24]
MRDATA[23:0]
MIE
VEC
MTAB
MTEAB
INT
ACK
STACK
Figure 3-16. ColdFire Mode Interrupt Acknowledge Bus Cycle
Clock 1 (C1)
The interrupt acknowledge cycle starts in C1. During the first half of C1, the ColdFire2/2M
drives the master address bus (MADDR[31:5]) high, MADDR[1:0] low, the MTT[1:0] signals
to $3, and the MADDR[4:2] and MTM[2:0] signals to the interrupt level. The master read/
write (MRWB) signal is driven high for a read cycle, and the master size signals (MSIZ[1:0])
indicate transfer size (Byte = $1). The ColdFire2/2M asserts the master transfer start
(MTSB) signal during C1 to indicate the beginning of a bus cycle.
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Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB. The interrupting device uses
the MRWB and MSIZ signals to place the vector number on the high-order byte of the
master read data bus (MRDATA[31:24]) and assert the master input enable (MIE) signal.
Concurrently, the interrupting device asserts the master transfer acknowledge (MTAB)
signal. At the end of C2, the ColdFire2/2M samples the level of MTAB and latches the
current value on MRDATA[31:24]. If MTAB is asserted, the transfer terminates. If MTAB is
not asserted, the ColdFire2/2M ignores the data and inserts wait states instead of
terminating the transfer. The ColdFire2/2M continues to sample MTAB on successive rising
edges of CLK until it is asserted. The interrupting device negates the MIE and MTAB signals
in the first half of the next CLK cycle.
See Figure 3-17 for an example of a 68K mode (IACK_68K asserted) interrupt acknowledge
cycle. The interrupt is shown occurring during a normal master bus read cycle with no lower-
order interrupts pending.
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Master Bus Operation
C1
C2
CLK
IPLB
MADDR[31:4]
MADDR[3:1]
MADDR[0]
MRWB
STACK
STACK
STACK
INT LEVEL
MSIZ
$1
MTT
$0
$5
MTM
INT LEVEL
MTSB
MWDATA
MWDATAOE
MRDATA[31:24]
MRDATA[23:0]
MIE
VEC
MTAB
MTEAB
INT
ACK
STACK
Figure 3-17. 68K Mode Interrupt Acknowledge Bus Cycle
Clock 1 (C1)
The interrupt acknowledge cycle starts in C1. During the first half of C1, the ColdFire2/2M
drives the master address bus (MADDR[31:4]), MADDR[0], and the MTM[2:0] signals high,
the MTT[1:0] signals low, and MADDR[3:1] to the interrupt level. The master read/write
(MRWB) signal is driven high for a read cycle, and the master size signals (MSIZ[1:0])
indicate transfer size (Byte = $1). The ColdFire2/2M asserts the master transfer start
(MTSB) signal during C1 to indicate the beginning of a bus cycle.
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Master Bus Operation
Clock 2 (C2)
During the first half of C2, the ColdFire2/2M negates MTSB. The interrupting device uses
the MRWB and MSIZ signals to place the vector number on the high-order byte of the
master read data bus (MRDATA[31:24]) and assert the master input enable (MIE) signal.
Concurrently, the interrupting device asserts the master transfer acknowledge (MTAB)
signal. At the end of C2, the ColdFire2/2M samples the level of MTAB and latches the
current value on MRDATA[31:24]. If MTAB is asserted, the transfer terminates. If MTAB is
not asserted, the ColdFire2/2M ignores the data and inserts wait states instead of
terminating the transfer. The ColdFire2/2M continues to sample MTAB on successive rising
edges of CLK until it is asserted. The interrupting device negates the MIE and MTAB signals
in the first half of the next CLK cycle.
3.7.2 Spurious Interrupt Acknowledge Bus Cycle
When a device does not respond to an interrupt acknowledge bus cycle with MTAB, the
external logic typically returns the transfer error acknowledge signal (MTEAB). In this case,
it is the responsibility of the external logic to return the spurious interrupt vector number 24
($18) on MRDATA[31:24] and assert MIE. The vector number will be latched on the first
rising edge of CLK after MTEAB is asserted. Because the spurious interrupt vector number
is returned on MRDATA[31:24] in the same manor as a normal interrupt acknowledge,
MTAB may be asserted instead of MTEAB.
3.8 MASTER BUS EXCEPTION CONTROL CYCLES
The ColdFire2/2M bus architecture requires assertion of MTAB from an external device to
signal that a bus cycle is complete. MTAB is not asserted in the following cases:
• The external device does not respond to a normal bus cycle.
• No interrupt vector is provided during an interrupt acknowledge cycle.
• Various other application-dependent errors occur.
External circuitry should assert MTEAB when no device asserts MTAB within an appropriate
period of time after the ColdFire2/2M begins the bus cycle. This terminates the cycle and
allows the ColdFire2/2M to enter exception processing for the error condition.
To properly control termination of a bus cycle for a access error, MTAB and/or MTEAB must
be asserted and negated for the same rising edge of CLK. Table 3-9 lists the control signal
combinations and the resulting bus cycle terminations. Note that the access error Exception
taken upon an MTEAB assertion cannot be masked and will occur for both reads and writes
that result in MTEAB being asserted. access error terminations during burst cycles operate
as described in Section 3.3.4 Line Read Transfer and Section 3.3.5 Line Write
Transfers.
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Table 3-9. MTAB and MTEAB Assertion Results
MTAB
MTEAB
RESULT
Don’t Care
Asserted
Access Error—Terminate and Take Access Error Exception
This exception cannot be masked
Asserted
Negated
Negated
Negated
Normal Cycle Terminate and Continue
Insert Wait States
3.8.1 Access Errors
The system hardware can use the MTEAB signal to abort the current bus cycle when a fault
is detected as shown in Figure 3-18. An access error is recognized during a bus cycle in
which MTEAB is asserted. When the ColdFire2/2M recognizes an access error condition,
the access is terminated immediately. A line access that has MTEAB asserted for one of the
four longword transfers aborts without completing the remaining transfers.
When MTEAB is asserted to terminate a bus cycle, the ColdFire2/2M can enter access error
exception processing immediately following the bus cycle, or it can defer processing the
exception in the following manner. The instruction prefetch mechanism requests instruction
words from the instruction memory unit before it is ready to execute them. If an access error
occurs on an instruction fetch, the ColdFire2/2M does not take the exception until it attempts
to use the instruction. Should an intervening instruction cause a branch or should a task
switch occur, the access error exception for the unused access does not occur. Similarly, if
an access error is detected on the second, third, or fourth longword transfer for a line read
access, an access error exception is taken only if the execution unit is specifically requesting
that longword. Otherwise, the line is not placed in the cache, and the ColdFire2/2M repeats
the line access when another access references the line. If a misaligned operand spans two
longwords in a line, an access error on either the first or second transfer for the line causes
exception processing to begin immediately. An access error termination for any write
accesses or for read accesses that reference data specifically requested by the execution
unit causes the ColdFire2/2M to begin exception processing immediately. Refer to Section
4Exception Processing for details of access error exception processing.
When an access error terminates an access, the contents of the corresponding cache can
be affected. For a cache line read to replace a valid instruction line, the cache line being filled
is invalidated before the bus cycle begins and remains invalid if the replacement line access
is terminated with an access error.
Note that if an access is made to a space that is masked, it simply becomes mapped to the
next valid space; no access error is generated. See Section 5.5, Interactions Between K-
Bus Memories, for further information. When a write error occurs on a buffered write, an
access error will be generated but will not be reported on the instruction that generated the
write.
Access errors only occur because of the following:
1)
MTEAB asserts
2) MMU error; i.e. trying to write in a write protected space
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Master Bus Operation
(RAMBAR, ROMBAR, ACR1, ACR0, and CACR have write protect bits)
3) Accessing CPU space from the debug module while the processor in NOT halted or
stopped
C1
A1
C2
C1
A2
C2
CLK
MADDR
MRWB
MSIZ
MTT
MTM
MTSB
MWDATA
MWDATAOE
MRDATA
MIE
D2
D1
MTAB
MTEAB
ERROR
STACK
Figure 3-18. Bus Exception Cycle
3.8.2 Fault-on-Fault Halt
A fault-on-fault error occurs when an access or address error occurs during the exception
processing sequence - e.g., the ColdFire2/2M attempts to stack several words containing
information about the state of the machine while processing an access error exception. If an
access error occurs during the stacking operation, the second error is considered a fault-on-
fault error. A second access or address error that occurs during execution of an exception
handler or later, does not cause a fault-on-fault condition. The ColdFire2/2M indicates a
fault-on-fault condition by continuously driving the processor status (PST[3:0]) signals with
an encoded value of $F until it is reset. Only an external reset operation can restart a halted
ColdFire2/2M. See Section 7.3.1 CPU Halt for more information.
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Master Bus Operation
3.9 RESET OPERATION
An external device asserts the MRSTB signal to reset the ColdFire2/2M. When power is
applied to the system, external circuitry should assert MRSTB for a minimum of six clock
cycles after V and CLK are within tolerance. The MRSTB signal is not internally
DD
synchronized and must meet the specified setup and hold times to CLK. If the external reset
is asynchronous, two flip-flops should be used to synchronize the signal before it drives
MRSTB.
Figure 3-19 shows the general relationship between V , MRSTB, and the bus signals
DD
during the power-on reset operation. Resets during normal operation must follow the same
requirements as those for power-on reset.
C1
VDD
CLK
MRSTB
BUS
MTSB
T >= 6 CYCLES
T = 22CYCLES
Figure 3-19. Initial Power-On Reset
3.10 MASTER BUS ARBITRATION
The ColdFire2/2M implementation is fully compatible with other, optional alternate Master’s.
The M-Bus supports arbitration; i.e. where the arbitration is performed in an external module
to the ColdFire2/2M. This arbitration module could function as a multiplexer-based master
switch. The ColdFire2/2M and the alternate masters generate master bus requests via their
individual bus connections, with the arbitration logic selecting between the masters on a
transfer-by-transfer basis.
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SECTION 4
EXCEPTION PROCESSING
Exception processing is the activity performed by the ColdFire2/2M in preparing to execute
a special routine, called an exception handler, for any condition that causes an exception.
Exception processing does not include execution of the routine itself.
This section describes the processing for each type of integer unit exception, exception
priorities, the return from an exception, and bus fault recovery. Also described are the
formats of the exception stack frames.
4.1 EXCEPTION PROCESSING OVERVIEW
Exception processing is the transition from the normal processing of a program to the
processing required for any special internal or external condition that preempts normal
processing. External conditions that cause exceptions are interrupts from external devices,
access errors, resets, and the assertion of the breakpoint signal. Internal conditions that
cause exceptions are address errors, instruction traps, illegal instructions, privilege
violations, tracing, format errors, and interrupts from the debug module. Exception
processing uses an exception vector table and an exception stack frame.
Exception processing for the ColdFire2/2M is streamlined for performance. Differences from
prior 68000 family processors are:
• A simplified exception vector table
• Reduced relocation capabilities using the vector base register (VBR)
• A fixed-length exception stack frame format
• Elimination of simultaneous multiple exception support
• Use of a single self-aligning system stack
Exception processing is comprised of four major steps and can be defined as the time from
the detection of the fault condition until the fetch of the first instruction of the exception
handler has been initiated. Figure 4-1 illustrates a general flowchart for the steps taken by
the ColdFire2/2M during exception processing.
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Exception Processing
ENTRY
SAVE INTERNAL
COPY OF SR
ENABLE SUPERVISOR
MODE & DISABLE TRACE
DETERMINE
VECTOR NUMBER
SAVE CONTENTS TO
EXCEPTION FRAME
(SEE NOTE)
(FAULT-ON-FAULT)
Y
ACCESS ERROR?
N
CALCULATE ADDRESS
OF
EXCEPTION HANDLER
FETCH FIRST
INSTRUCTION OF
EXCEPTION HANDLER
(FAULT-ON-FAULT)
Y
ACCESS/ADDRESS
ERROR?
N
BEGIN EXECUTION
OF
HALTED
EXCEPTION HANDLER
STATE
EXIT
EXIT
NOTE: THIS BLOCK VARIES FOR RESET AND INTERRUPT EXCEPTIO
Figure 4-1. Exception Processing Flowchart
The processing of an exception on the ColdFire2/2M is composed of the following steps:
1. The ColdFire2/2M makes an internal copy of the status register (SR) and then enters
supervisor mode by setting the S-bit and disabling trace mode by clearing the T-bit in
the SR. The occurrence of an interrupt exception also forces the master/interrupt bit,
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M-bit, in the SR to be cleared and the interrupt priority mask, I[2:0], in the SR to be set
to the level of the current interrupt request
2. The ColdFire2/2M determines the exception vector number. For all faults except
interrupts, the ColdFire2/2M performs this calculation based on the exception type.
For interrupts, the ColdFire2/2M performs an interrupt acknowledge (IACK) bus cycle
to obtain the vector number from a peripheral device. The IACK cycle is mapped to a
special acknowledge address space with the interrupt level encoded in the address.
Refer to Section 3.7 Interrupt Acknowledge Bus Cycles.
3. The ColdFire2/2M saves the current context by creating an exception stack frame on
the system stack. The ColdFire2/2M supports a single stack pointer (SP) in the A7
address register, i.e., there is no notion of separate supervisor- or user- stack pointers.
As a result, the exception stack frame is created at a 0-modulo-4 address on the top
of the current system stack. Additionally, the ColdFire2/2M uses a simplified fixed-
length exception stack frame for all exceptions. The exception type determines
whether the program counter placed in the exception stack frame defines the location
of the faulting instruction or the address of the next instruction to be executed.
4. The ColdFire2/2M calculates the address of the first instruction of the exception
handler. By definition, the exception vector table is aligned on a 1 MByte boundary.
This instruction address is generated by fetching an exception vector from the table
located at the address defined in the vector base register. The index into the exception
table is calculated as (4 x vector_number). Once the exception vector has been
fetched, the contents of the vector determine the address of the first instruction of the
desired exception handler. After the instruction fetch for the first opcode of the
exception handler has been initiated, exception processing terminates and normal
instruction processing continues in the exception handler.
4.1.1 Exception Stack Frame Definition
A diagram of the exception stack frame is shown in Figure 4-2. The first long word of the
exception stack frame, pointed to by SP, contains the 16-bit format/vector word (F/V) and
the 16-bit status register, and the second long word contains the 32-bit program counter
address.
31
28 27 26 25
18 17 16 15
FS[1:0]
0
FORMAT
FS[3:2]
VECTOR[3:2]
STATUSREGISTER
PROGRAMCOUNTER[31:0]PC
Figure 4-2. Exception Stack Frame Form
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Exception Processing
Field Definitions:
FORMAT—Exception Frame Format
This field is always written with a value of $4, $5, $6, or $7 by the ColdFire2/2M indicating a
two long-word frame format. The specific value depends on the value of the stack pointer
(SP) before the exception occurred.
0100 = Original SP[1:0] set to 00
0101 = Original SP[1:0] set to 01
0110 = Original SP[1:0] set to 10
0111 = Original SP[1:0] set to 11
FS—Fault Status
This field is defined for access and address errors only and written as zeros for all other
types of exceptions.
0000 = Not address or access error
0001 = Reserved
001x = Reserved
0100 = Error on instruction fetch
0101 = Reserved
011x = Reserved
1000 = Error on operand write
1001 = Attempted write to write-protected space
101x = Reserved
1100 = Error on operand read
1101 = Reserved
111x = Reserved
VECTOR—Exception Vector Number
This 8-bit vector number defines the exception vector number used to index into the
exception vector table. For internal exceptions, this number is calculated by the ColdFire2/
2M, and for external interrupts, this number is read during the IACK cycle as described in
Section 3.7 Interrupt Acknowledge Bus Cycles. Refer to Table 4-2 for exception vector
assignments.
PC—Program Counter
This field contains the 32-bit program counter at the time of the exception. The instruction
at this address is the faulting instruction or the next instruction depending on the type of
exception.
4.1.1.1 SELF-ALIGNING STACK. The ColdFire2/2M aligns the stack to a longword
boundary before the exception stack frame is placed on the stack. As a result, the difference
between the SP before the exception and the SP at the start of the exception handler may
be more than two longwords, but the location of the exception stack frame is always at the
top of the stack. As seen in Table 4-1, the format field reflects the SP alignment and is used
when an RTE instruction executes to correctly restore the SP to its original value.
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Table 4-1. Stack Pointer Alignment
ORIGINAL SP [1:0] @
TIME OF EXCEPTION,
SP @ 1ST INSTRUCTION
OF EXCEPTION HANDLER
FORMAT FIELD
00
01
10
11
0100
0101
0110
0111
(Original SP) - 8
(Original SP) - 9
(Original SP) - 10
(Original SP) - 11
4.1.2 Exception Vectors
The ColdFire2/2M supports a 1024-byte vector table aligned on any 1 MByte address
boundary (see Table 4-2). The table contains 256 exception vectors where the first 64 are
defined by Motorola and the remaining 192 are user-defined.The exception table order does
not have any priority. It is an area in memory reserved for the storage of the first address
used within the different exception handler routines. The reserved areas in the exception
table are for future expansion and can be used as long as the application does not care if
these areas become valid regions in future ColdFire processors.
Table 4-2. Exception Vector Assignments
VECTOR
OFFSET
STACKED
PROGRAM
COUNTER
VECTOR NUMBER
ASSIGNMENT
HEX
$0
DECIMAL
HEX
$000
0
1
-
Reset Initial Stack Pointer
Reset Initial Program Counter
Access Error
$1
$004
-
$2
2
$008
Fault
Fault
Fault
-
$3
3
$00C
Address Error
$4
4
$010
Illegal Instruction
$5-$7
$8
5-7
8
$014-$01C
$020
Reserved
Fault
Next
Fault
Fault
Next
-
Privilege Violation
$9
9
$024
Trace
$A
10
$028
Unimplemented Line-A Opcode
Unimplemented Line-F Opcode
Debug Interrupt
$B
11
$02C
$C
12
$030
$D
13
$034
Reserved
$E
14
$038
Fault
Next
-
Format Error
$F
15
$03C
Optional Uninitialized Interrupt
Reserved
$10-$17
$18
16-23
24
$040-$05C
$060
Next
Next
Next
-
Optional Spurious Interrupt
Optional Level 1-7 Autovectored Interrupts
TRAP # 0-15 Instructions
Reserved
$19-$1F
$20-$2F
$30-$3F
$40-$FF
25-31
32-47
48-63
64-255
$064-$07C
$080-$0BC
$0C0-$0FC
$100-$3FC
Next
User-Defined Interrupts
NOTES: 1. “Fault” refers to the PC of the instruction that caused the exception
2. “Next” refers to the PC of the next instruction that follows the instruction that caused
the fault.
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Exception Processing
The ColdFire2/2M inhibits sampling for interrupts during exception processing, including the
first instruction of the exception handler. This allows the first instruction of any exception
handler to effectively disable interrupts, if desired, by raising the interrupt mask level
contained in the status register.
Normally, the end of an exception handler contains an RTE instruction. When the ColdFire2/
2M executes the RTE instruction, it examines the exception stack frame on top of the stack
to determine if it is a valid frame. If the ColdFire2/2M determines that it is a valid frame, the
SR and PC fields are loaded from the exception stack frame and control is passed to the
specified instruction address. If the frame is invalid, a format exception is taken.
All exception vectors are located in the supervisor data space. Since the vector base register
(VBR) provides the base address of the exception vector table, the exception vector table
can be located anywhere in memory; it can even be dynamically relocated for each task that
an operating system executes. The VBR is reset to zero. Refer to Section 1.4.3.4 Vector
Base Register (VBR).
4.1.3 Multiple Exceptions
Within a ColdFire2/2M system, more than one exception can occur at the same time. When
this occurs, only the exception with the highest priority will be processed. Exceptions can be
divided into the four basic groups identified in Table 4-3.
Table 4-3. Exception Priority Groups
GROUP
PRIORIT
Y
EXCEPTION AND
RELATIVE PRIORITY
CHARACTERISTICS
0.0
Reset
The ColdFire2/2M aborts all processing (instruction or exception) and does not save old
context.
1.0
1.1
1.2
Address Error
Instruction Access
The ColdFire2/2M suspends processing and saves the context.
Error
Data Access Error
2.0
2.1
2.2
2.3
A-Line
Unimplemented
F-Line
Unimplemented
Illegal Instruction
Privilege Violation
Exception processing begins before the instruction is executed.
TRAP Instruction
Format Error
Exception processing is part of the instruction execution and begins after instruction
execution.
3.0
4.0
4.1
4.2
Trace
Exception processing begins when the current instruction is completed.
Debug Interrupt
Interrupt
NOTES: 1. 0.0 is the highest priority.
2. 4.2 is the lowest priority.
These groups are defined by specific characteristics and the priority with which they are
handled. As far as the ColdFire2/2M is concerned, the interrupt exception will never appear
to occur at the same time as another exception. Interrupt exceptions will remain pending
until the other exception is processed. Refer to Section 4.2.6 Trace Exception for an
example of simultaneous exceptions.
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4.1.4 Fault-on-Fault Halt
If the ColdFire2/2M encounters any type of fault during the exception processing of another
fault, it immediately halts execution with the catastrophic fault-on-fault condition. The
ColdFire2/2M indicates a fault-on-fault condition by continuously driving the processor
status (PST[3:0]) signals with an encoded value of $F until it is reset. Only an external reset
operation can restart a halted ColdFire2/2M. See Section 7.3.1 CPU Halt for more
information.
4.2 EXCEPTIONS
The following paragraphs describe the external interrupt exceptions and the different types
of exceptions generated internally by the integer unit. The following exceptions are dis-
cussed:
• Reset
• Access Error
• Address Error
• Illegal Instruction
• Privilege Violation
• Trace
• Unimplemented Opcode
• Debug Interrupt
• Format Error
• TRAP Instruction
• External Interrupt
4.2.1 Reset Exception
Asserting the reset input signal to the ColdFire2/2M causes a reset exception, vector
number $0. The reset exception has the highest priority of any exception; it provides for
system initialization. Reset also aborts any processing in progress when the reset input is
recognized, and the aborted processing cannot be recovered.
The reset exception places the ColdFire2/2M in the supervisor mode by setting the S-bit and
disables tracing by clearing the T-bit in the SR. This exception also clears the M-bit and sets
the ColdFire2/2M’s interrupt priority mask in the SR to the highest level (level 7). Next, the
VBR, CACR, ACRs, RAMBAR0, and ROMBAR0 are initialized to their reset value. This will
disable the cache, SRAM, and optionally the ROM (see Section 5.3.2 ROM Programming
Model.)
Once the ColdFire2/2M is granted the bus, and it does not detect any other alternate
masters taking the bus, the core then performs two longword read bus cycles. Because the
VBR is reset to zero, the first longword is always loaded into the stack pointer from address
zero, and the second longword is always loaded into the program counter from address four.
After the initial instruction is fetched from memory, program execution begins at the address
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Exception Processing
in the PC. If an access error or address error occurs before the first instruction begins
execution, the ColdFire2/2M enters the fault-on-fault halted state. Refer to Section 3.9
Reset Operation for more information on initiating a reset exception.
4.2.2 Access Error Exception
An access error exception, vector number $2, occurs when a bus cycle terminates with an
error condition such as the assertion of the master transfer error acknowledge (MTEAB)
signal. Refer to Section 3.8 Master Bus Exception Control Cycles. The exact response to an
access error is dependent on the type of memory reference being performed.
For an instruction fetch, the ColdFire2/2M postpones the reporting of an error until the
faulted reference is needed by an instruction to be executed. Thus, faults which occur during
instruction prefetches which are then followed by a change of instruction flow will not
generate an exception. When the ColdFire2/2M attempts to execute an instruction with a
faulted opword and/or extension words, the access error will be signaled and the instruction
aborted. For this type of exception, the programming model has not been altered by the
instruction generating the access error.
If the access error occurs on an operand read, the ColdFire2/2M immediately aborts the
current instruction’s execution and initiates exception processing. In this situation, any
address register updates due to the auto-addressing modes, {e.g., (An)+,-(An)}, will already
have been performed. Thus, the programming model contains the updated An value. In
addition, if an access error occurs during the execution of a MOVEM instruction loading
registers from memory, any registers already updated before the fault occurs will contain the
operands from memory.
The ColdFire2/2M uses an imprecise reporting mechanism for access errors on write
operations. Since the actual write cycle may be decoupled from the ColdFire2/2M’s
execution of the instruction requesting the write, the signaling of an access error appears to
be decoupled from the instruction which generated the write. Accordingly, the PC contained
in the exception stack frame merely represents the location in the program when the access
error was signaled, not when the offending instruction was executed. All programming
model updates associated with the write instruction are completed. The NOP instruction can
be used for purposes of collecting access errors for writes. This instruction delays its
execution until all previous operations, including all pending write operations to internal
memory resources, are complete. Noncachable writes to the master bus may be buffered
but will be completed before the execution of a NOP instruction. The NOP instruction waits
until the pipeline is cleared out, including buffered writes before executing. Generally,
buffering can provide higher performance, although issues concerning recovery from
physical write-errors may become more difficult to resolve.
4.2.3 Address Error Exception
Any attempted execution transferring control to an odd instruction address (i.e., if bit 0 of the
target address is set) results in an address error exception, vector number $3. For
conditional branch instructions, the exception is generated regardless of the taken/not-taken
resolution of the branch condition.
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The ColdFire2/2M has a misalignment unit which will generate a series of aligned bus cycles
to access data requested from a misaligned address. As a result, misaligned operand
fetches will not cause an address error exception.
Any attempted use of a word-sized index register (Xn.w) or an invalid scale factor on an
indexed effective addressing mode generates an address error. The setting of the extension
word valid (EV) bit on an indexed addressing mode instruction will also generate an address
error. Refer to the ColdFire Programmer’s Reference Manual Rev. 1.0 (MCF5200PRM/AD).
4.2.4 Illegal Instruction Exception
The attempted execution of the $0000 and the $4AFC opwords generates an illegal
instruction exception, vector number $4. The ColdFire2/2M does not provide illegal
instruction detection on the extension words on any instruction, including MOVEC. If any
other non-supported opcode is executed, the resulting operation is undefined and the
ColdFire2/2M’s behavior is unpredictable.
4.2.5 Privilege Violation Exception
The attempted execution of a supervisor mode instruction while in user mode generates a
privilege violation exception, vector number $8. See the ColdFire Programmer’s Reference
Manual Rev. 1.0 for lists of supervisor- and user- mode instructions.
4.2.6 Trace Exception
To aid in program development, the ColdFire2/2M provides an instruction-by-instruction
tracing capability. While in trace mode, indicated by the setting of the T-bit in the status
register (SR[15] = 1), the completion of an instruction execution triggers a trace exception,
vector number $9. This functionality allows a debugger to monitor program execution.
The single exception to this definition is the STOP instruction. A STOP instruction that
begins execution in trace mode (T-bit in SR set) or enters trace mode because of the STOP
instruction execution (bit 15 of the STOP operand is set) forces a trace exception after it
loads the SR. Upon return from the trace exception handler, execution continues with the
instruction following the STOP instruction, and the ColdFire2/2M never enters the stopped
condition. A STOP instruction will enter the stopped state only if the ColdFire2/2M is not in
trace mode before the STOP instruction is executed and the STOP instruction does not
place the ColdFire2/2M in the trace mode.
Since theColdFire2/2M does not support hardware stacking of multiple exceptions, it is the
responsibility of the operating system to check for trace mode after processing other
exception types. As an example, consider the execution of a TRAP instruction while in trace
mode. The ColdFire2/2M will initiate the TRAP exception and then pass control to the
corresponding exception handler, clearing the trace bit (T-bit) in the SR. If the system
requires that a trace exception be processed, it is the responsibility of the TRAP exception
handler to check for this condition, SR[15] in the exception stack frame, and pass control to
the trace exception handler before returning from the original exception.
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Exception Processing
A trace exception does not occur immediately after the execution (MOVE to SR, RTE) of the
instruction that puts the ColdFire2/2M in trace mode. The first trace exception occurs after
the subsequent instruction.
4.2.7 Unimplemented Opcode Exception
The attempted execution of line A opcodes not used for MAC instructions and line F
opcodes not used for the debug instructions, including $FFFF, generates their unique
exception types, vector numbers $A and $B respectively. Refer to Appendix B New MAC
Instructions for a list of the MAC opcodes and the ColdFire Programmer’s Reference
Manual Rev. 1.0 for a list of the debug instruction opcodes.
4.2.8 Debug Interrupt
The debug module is the only internal interrupt source for the ColdFire2/2M. This type of
program interrupt, vector number $C, is discussed in detail in Section 7.4 Real-Time
Debug Support. This exception is generated in response to a hardware breakpoint register
trigger. The ColdFire2/2M does not generate an IACK cycle, but rather calculates the vector
number internally.
4.2.9 RTE & Format Error Exceptions
When an RTE instruction is executed, the ColdFire2/2M first examines the 4-bit format field
in the exception stack frame on the stack to validate the frame type. Any attempted
execution of an RTE when the format is not equal to $4, $5, $6, or $7 generates a format
error, vector number $E. The exception stack frame for the format error is created without
disturbing the original exception stack frame. The PC field in the new exception stack frame
will point to the RTE instruction.
The selection of the format value provides some limited debug support for porting code from
68000 applications. On 680x0 family processors, the status register (SR) was located at the
top of the stack. On those processors, bit[30] of the longword addressed by the system stack
pointer (SP) is typically zero. Thus, if an RTE is attempted with a 680x0-type exception stack
frame, the ColdFire2/2M will generate a format exception.
If the format field defines a valid type, the ColdFire2/2M: (1) reloads the SR operand, (2)
fetches the second long word operand (PC), (3) adjusts the stack pointer by adding the
format value to the auto-incremented address after the fetch of the first long word, and then
(4) transfers control to the instruction address defined by the PC (fetched in step 2.)
4.2.10 TRAP Instruction Exceptions
The TRAP instruction always forces an exception as part of its execution and is useful for
implementing system calls. The instruction adds the immediate operand (vector) of the
instruction to 32 to obtain the vector number. The range of vector values is 0 - 15, which
provides 16 vectors numbered $20 - $2F. Refer to the ColdFire Programmers Reference
Manual Rev. 1.0 (MCF5200PRM/AD) for more information on the TRAP instruction.
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4.2.11 Interrupt Exception
When a peripheral device requires the services of the ColdFire2/2M or is ready to send
information that the ColdFire2/2M requires, it can signal the ColdFire2/2M to take an
interrupt exception. Seven levels of interrupt priorities are provided, numbered 1–7. Devices
can be chained externally within interrupt priority levels, allowing an unlimited number of
peripheral devices to interrupt the ColdFire2/2M. The status register contains a 3-bit mask
indicating the current interrupt priority, and interrupts are inhibited for all priority levels less
than or equal to the current priority (see Section 1.4.3.1 Status Register (SR).)
An interrupt request is made to the ColdFire2/2M by encoding the interrupt request levels
1–7 on the three interrupt request level (IPLB[2:0]) signals; all signals high indicate no
interrupt request. Table 4-4 shows the relationship between the actual requested interrupt
and the state of the IPLB[2:0] signals as well as the interrupt mask levels required for
recognition of the requested level.
Table 4-4. Interrupt Levels and Mask Values
CONTROL LINE STATUS
INTERRUPT MASK LEVEL
REQUESTED
INTERRUPT LEVEL
REQUIRED FOR RECOGNITION
IPLB[2] IPLB[1] IPLB[0]
0
1
2
3
4
5
6
7
High
High
High
High
Low
Low
Low
Low
High
High
Low
Low
High
High
Low
Low
High
Low
High
Low
High
Low
High
Low
No Request
0
0-1
0-2
0-3
0-4
0-5
0-7
Interrupt requests arriving at the ColdFire2/2M do not force immediate exception
processing, but the requests are made pending. Pending interrupts are detected between
instruction executions. If the priority of the pending interrupt is lower than or equal to the
current ColdFire2/2M priority, execution continues with the next instruction, and the
requesting interrupt is postponed until the priority of the pending interrupt becomes greater
than the current ColdFire2/2M priority.
If the priority of the pending interrupt is greater than the current ColdFire2/2M priority, the
exception processing sequence for the requesting interrupt is started. A copy of the status
register is saved internally; the privilege mode is set to supervisor mode; tracing is
suppressed; and the ColdFire2/2M priority level is set to the level of the interrupt being
acknowledged. The ColdFire2/2M fetches the vector number from the interrupting device by
executing an interrupt acknowledge cycle, which displays the level number of the interrupt
being acknowledged on the address bus (see Section 3.7 Interrupt Acknowledge Bus
Cycles). The ColdFire2/2M then proceeds with the usual exception processing, saving the
exception stack frame on the supervisor stack. The saved value of the program counter is
the address of the instruction that would have been executed had the interrupt not been
taken. The appropriate interrupt vector is fetched and loaded into the program counter, and
normal instruction execution commences in the interrupt handling routine.
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Interrupt requests should be maintained on the IPLB[2:0] signals until the conclusion of the
interrupt acknowledge (IACK) cycle from the processor to guarantee that the interrupt will
be recognized. The interrupt request can be maintained without being recognized again,
until the interrupt priority level in the SR is lowered below the currently requested level. This
is usually the result of the RTE instruction at the end of the interrupt exception handler.
Once the conclusion of an Interrupt Acknowledge (IACK) cycle occurs, another interrupt
may be asserted on the IPLB lines.The processor will start fetching the interrupt handler
code for the acknowledged interrupt. In the handler, the processor looks at the interrupt
mask level and determines if the second interrupt is masked or allowed.If the second
interrupt is not masked, the processor will start another IACK cycle for the second interrupt.
It will go to the second interrupt handler and sample IPLB inputs, compare mask, and
execute this handler if a higher level interrupt is not pending. Once the second interrupt has
completed the return from exception (RTE) in the handler, the processor will return to the
first interrupt handler, where the IPLB lines are sampled and compared to the interrupt
mask. If no interrupts have higher priority, it will execute this handler and return (RTE) to the
place in the code where the first interrupt was allowed to be taken.
Thus, interrupts can be nested, and higher interrupts given priority by the interrupt mask
register once they are executing code within the handlers.
4.2.11.1 LEVEL 7 INTERRUPTS. Level 7 interrupts are handled differently than interrupt
levels one through six. A level 7 interrupt is a nonmaskable interrupt; therefore, a 7 in the
interrupt mask does not disable a level 7 interrupt.
Level 7 interrupts are edge-triggered by a transition from a lower priority request to the level
7 request, as opposed to interrupt levels one through six, which are level sensitive.
Therefore, if the interrupt priority level (IPLB[2:0]) signals remain at level 7, the ColdFire2/
2M will only recognize one level 7 interrupt since only one transition from a lower level
request to a level 7 request occurred. For the ColdFire2/2M to recognize a level 7 interrupt
followed by another level 7 interrupt, one of the two following sequences must occur:
1. The interrupt request level on the IPLB[2:0] signals changes from a lower request level
to level 7 and remains at level 7 until the interrupt acknowledge bus cycle begins.
Later, the interrupt request level returns to a lower interrupt request level and then
back to level 7, causing a second transition on the IPLB[2:0] signals.
2. The interrupt request level on the IPLB[2:0] signals changes from a lower request level
to level 7 and remains at level 7. If the interrupt handling routine for the level 7 interrupt
lowers the interrupt mask level, a second level 7 interrupt will be recognized even
though no transition has occurred on the interrupt control pins. After the level 7
interrupt handling routine completes, the ColdFire2/2M will compare the interrupt
mask level to the interrupt request level on the IPLB[2:0] signals. Since the interrupt
mask level will be lower than the requested level, the interrupt mask will be set back
to level 7. The level 7 request on the IPLB[2:0] signals must be held until the second
interrupt acknowledge bus cycle has begun to ensure that the interrupt is recognized.
4.2.11.2 SPURIOUS, AUTOVECTORED, AND UNINITIALIZED INTERRUPTS. If When
the external logic indicates an access error during the interrupt acknowledge cycle, the
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interrupt is considered spurious (refer to Section 3.7.2 Spurious Interrupt Acknowledge Bus
Cycle.) It is the responsibility of the external logic to return the spurious interrupt vector
number, $18. External hardware may also be designed to generate autovector interrupts,
$64 - $7C, for each interrupt level. Many M68000 family peripherals use programmable
interrupt vector numbers as part of the interrupt-acknowledge operation for the system. If
this vector number is not initialized after reset and the peripheral must acknowledge an
interrupt request, the peripheral usually returns the vector number for the uninitialized
interrupt vector, $F.
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SECTION 5
INTEGRATED MEMORIES
The ColdFire2/2M has dedicated buses to support three integrated memories: instruction
cache, RAM, and ROM.
5.1 INSTRUCTION CACHE
The ColdFire2/2M has a dedicated bus to support an integrated instruction cache with the
following features:
• 0 - 32 Kbyte direct-mapped instruction cache
• Instruction cache byte size programmed with ICH_SZ[2:0] static signals
• Single-cycle access on cache hits
• Physically located on processor’s high-speed local bus
• Non-blocking design to maximize performance
• Configurable cache-miss fetch algorithm
The cache module services instruction-fetch requests from the ColdFire2/2M by either
returning matching 32-bit cache entries in a single clock, or by initiating memory requests to
service accesses that miss in the cache. The instruction cache size is specified via the
ICH_SZ[2:0] pins which are static signals that need to stay valid for all operation. Only the
ColdFire2/2M can access the cache. A fetch is defined as a read from user or supervisor
code space only.
5.1.1 Instruction Cache Hardware Organization
The instruction cache is an optional direct-mapped single-cycle memory, organized as 32
(512 byte) to 2K (32 Kbyte) lines, each containing 4 longwords or 16 bytes. The data array
is organized in longwords, 4 bytes per entry. The tag array is organized in lines, one entry
per four longwords or line. The cache size is determined by the encoding of the ICH_SZ[2:0]
inputs as shown in Table 5-1. Thus the memory storage consists of a N-entry tag array
(where N corresponds to the number of lines in the data array) containing addresses and a
valid bit, and the data array containing M bytes of instruction data (where M= 512,1K, 2K,
4K, 8K, 16K, or 32K), organized as M/4 x 32 bits.
The two memory arrays are accessed in parallel: bits [X:4] of the instruction fetch address
providing the index into the tag array, and bits [X:2] addressing the data array (where X
ranges from 8 to 14 for 512-byte to 8K-byte I-cache size, see Table 5-1).The tag array
outputs the address mapped to the given cache location along with the valid bit for the line.
This address field is compared to bits [31:Y] of the instruction fetch address (where Y = X +
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1 for a given cache size) from the local bus to determine if a cache hit in the memory array
has occurred. If the desired address is mapped into the cache memory, the output of the
data array is driven onto the processor’s local data bus completing the access in a single
cycle.
The tag array maintains a single valid bit per line entry. Accordingly, only entire 16-byte lines
are loaded into the instruction cache.
The instruction cache also contains a 16-byte fill buffer which provides temporary storage
for the last line fetched in response to a cache miss. With each instruction fetch, the contents
of the line fill buffer are examined. Thus, each instruction fetch address examines both the
tag memory array and the line fill buffer to see if the desired address is mapped into either
hardware resource, with the line fill buffer having priority over the instruction cache. A “cache
hit” in either the memory array or the line fill buffer is serviced in a single cycle. Since the
line fill buffer maintains valid bits on a longword basis, hits in the buffer can be serviced
immediately without waiting for the entire line to be fetched.
If the referenced address is not contained in the memory array nor the line fill buffer, the
instruction cache initiates the required external fetch operation. In most situations, this is a
16-byte line-sized burst reference. An external bus cycle is always started simultaneously
with the fetch cycle to the instruction cache. If a “hit” occurs in the instruction cache, the
MKILLB signal is asserted late in the cycle to “kill” the external bus cycle. Thus an asserted
MTSB and MKILLB direct the external bus controller to ignore the MTSB. If no “hit” occurred
in the instruction cache (or other K-Bus memory), the M-Bus cycle uses the normal number
of clock cycles beginning with the MTSB issued for the instruction fetch. See Section 5.5,
Interactions Between K-Bus Memories for more details.
The hardware implementation is a non-blocking design, meaning the processor’s local bus
is released after the initial access of a miss. Thus, the cache, RAM, or ROM module can
service subsequent requests while the remainder of the line is being fetched and loaded into
the fill buffer.
5.1.2 Instruction Cache Operation
The instruction cache is physically connected to the processor’s local bus allowing it to
service all instruction fetches from the ColdFire CPU and certain memory fetches initiated
by the debug module. Typically, the debug modules’s memory references appear as
supervisor data accesses, but the unit may be programmed to generate user mode
accesses and/or instruction fetches. Any instruction fetch access is processed by the
instruction cache in the normal manner.
5.1.3 Instruction Cache Signal Description
The following signals interface the ColdFire2/2M to an integrated instruction cache. The
cache is comprised of two compiled RAMs: tag and data. Figure 5-1 illustrates an 8 Kbyte
configuration. All ColdFire2/2M signals are unidirectional and synchronous. Instruction
cache outputs are registered and the Instruction cache data is latched into the ColdFire2/2M
on the falling edge of the clock.
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TAG RAM
CSB
CPU CORE
ICHT_CSB
[31:13,8]
ICHT_DI[31:8]
DBI[19:0]
[31:13,8]
ICHT_DO[31:8]
DBO[19:0]
[12:9]
GND
ICHT_ST
ST
ICHT_RWB
RWB
A[8:0]
[12:4]
[12:2]
[12:2]
ICH_ADDR[14:2]
DATA RAM
A[10:0]
ICHD_CSB
CSB
[31:0]
[31:0]
ICHD_DI[31:0]
DBI[31:0]
ICHD_DO[31:0]
ICHD_ST
DBO[31:0]
ST
ICHD_RWB
ICH_SZ[2:0]
RWB
[2:0]
SIZE
Figure 5-1. Example of 8 Kbyte Instruction Cache Interface Diagram
5.1.3.1 INSTRUCTION CACHE ADDRESS BUS (ICH_ADDR[14:2]). These registered
output signals provide the address of the current bus cycle (i.e. fetch cycle) to the integrated
cache RAMs. ICH_ADDR is only updated on fetch cycles (i.e. ICH_ADDR does not get
updated on RAM or ROM hits). This bus should be connected to the address bus (A) of the
two compiled cache RAMs. ICH_ADDR[N:M] is being provided via MADDR[N:M].
5.1.3.2 INSTRUCTION CACHE DATA CHIP-SELECT (ICHD_CSB). This active-low,
output signal indicates the cache data RAM is currently selected to perform a data transfer
with the ColdFire2/2M. This bus should be connected to the chip-select (CSB) signal of the
compiled cache data RAM.
5.1.3.3 INSTRUCTION CACHE DATA INPUT BUS (ICHD_DI[31:0]). These output
signals provide the write data path between the ColdFire2/2M and the cache data RAM. The
data bus is 32-bits wide and should be connected to the data inputs (DBI) of the compiled
cache data RAM.
5.1.3.4 INSTRUCTION CACHE DATA OUTPUT BUS (ICHD_DO[31:0]). These input
signals provide the read data path between the cache data RAM and the ColdFire2/2M. The
data bus is 32-bits wide and should be connected to the data outputs (DBO) of the compiled
cache data RAM.
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5.1.3.5 INSTRUCTION CACHE DATA STROBE (ICHD_ST). This output signal initiates a
read or write cycle to the cache data RAM on a low-to-high transition. This signal should be
connected to the strobe input (ST) signal of the compiled cache data RAM.
5.1.3.6 INSTRUCTION CACHE DATA READ/WRITE (ICHD_RWB). This output signal
indicates the direction of the data transfer to the cache data RAM. A high level indicates a
read cycle and a low level indicates a write cycle. It should be connected to the read/write
(RWB) signal of the compiled cache data RAM.
5.1.3.7 INSTRUCTION CACHE SIZE (ICH_SZ[2:0]). These static inputs specify the size
of the compiled cache RAMs connected to the ColdFire2/2M. Table 5-1 lists the possible
cache configurations. ICH_SZ[2:0] does not affect the CACR in any way; thus a MOVEC
instruction will write the CACR regardless of the ICH_SZ specification (which is contrary to
the RAM_SZ and ROM_SZ effect during RAMBAR and ROMBAR loading).
Table 5-1. Cache Configuration Encoding
ICACHE SZ
(BYTES)
ICH_SZ[2:0]
TAG ARRAY
SIZE
TAG ARRAY
ADDRESS
DATA ARRAY DATA ARRAY
SIZE
ADDRESS
None
512
000
001
010
011
100
101
110
111
-
-
-
-
32x24
64x23
128x22
256x21
512x20
1Kx19
2Kx18
ICH_ADDR[8:4]
ICH_ADDR[9:4]
ICH_ADDR[10:4]
ICH_ADDR[11:4]
ICH_ADDR[12:4]
ICH_ADDR[13:4]
ICH_ADDR[14:4]
128x32
256x32
512x32
1Kx32
2Kx32
4Kx32
8Kx32
ICH_ADDR[8:2]
ICH_ADDR[9:2]
ICH_ADDR[10:2]
ICH_ADDR[11:2]
ICH_ADDR[12:2]
ICH_ADDR[13:2]
ICH_ADDR[14:2]
1 K
2 K
4 K
8 K
16K†
32K†
NOTE: †HPF65 ColdFire2 Hard Macro may require a reduced operating frequency for 16K and 32K sized
ICACHE.
5.1.3.8 INSTRUCTION CACHE TAG CHIP-SELECT (ICHT_CSB). This active-low output
signal indicates the cache tag RAM is currently selected to perform a data transfer with the
ColdFire2/2M. This signal should be connected to the chip-select (CSB) signal of the
compiled cache tag RAM.
5.1.3.9 INSTRUCTION CACHE TAG INPUT BUS (ICHT_DI[31:8]). These output signals
provide the write data path between the ColdFire2/2M and the cache tag RAM. The data bus
depends upon the size of the CACHE; see Table 5-1. Bit eight is always the valid bit and is
always used as seen in the cache configuration shown in Table 5-2. This bus should be
connected to the data inputs (DBI) of the compiled cache tag RAM. Functionally,
MADDR[31:9] is written onto ICHT_DI[31:9] and ICHT_DI[8] is written with the valid state of
the entry.
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Table 5-2. Valid Tag RAM Data Signals
CACHE SIZE
CPU DATA PLACED ON
VALID DATA BITS
VALID DATA BITS
(BYTES)
512
ICHT_Dx[31:8]
ICHT_Dx[31:10,8]
ICHT_Dx[31:11,8]
ICHT_Dx[31:12,8]
ICHT_Dx[31:13,8]
ICHT_Dx[31:14,8]
ICHT_Dx[31:15,8]
{MADDR[31:9], VALID}
MADDR[31:10], VALID}
MADDR[31:11], VALID}
MADDR[31:12], VALID}
MADDR[31:13], VALID}
MADDR[31:14], VALID}
MADDR[31:15], VALID}
1 K
2 K
4 K
8 K
16K
32K
5.1.3.10 INSTRUCTION CACHE TAG OUTPUT BUS (ICHT_DO[31:8]). These input
signals provide the read data path between the cache tag RAM and the ColdFire2/2M. The
data bus size depends upon the size of the CACHE; see Table 5-1. Bit eight is always the
valid bit and is always used regardless of the cache configuration as shown in Table 5-2.
This bus should be connected to the data outputs (DBO) of the compiled cache tag RAM.
Unused signals must be tied low.
5.1.3.11 INSTRUCTION CACHE TAG STROBE (ICHT_ST). This output signal initiates a
read or write cycle to the cache tag RAM on a low-to-high transition. This signal should be
connected to the strobe input (ST) signal of the compiled cache tag RAM.
5.1.3.12 INSTRUCTION CACHE TAG READ/WRITE (ICHT_RWB). This output signal
indicates the direction of the data transfer to the cache tag RAM. A high level indicates a
read cycle and a low level indicates a write cycle. It should be connected to the read/write
(RWB) signal of the compiled cache tag RAM.
5.1.4 Interaction With Other Modules
Since the instruction cache, high-speed ROM and RAM modules are connected to the
processor’s local data bus, certain user-defined configurations may result in simultaneous
instruction fetch processing. If the referenced address is mapped into the ROM or RAM
module, that module will service the request in a single cycle. In this case, data accessed
from the instruction cache is simply discarded, and no external memory references are
generated. The RAM module has higher priority over the ROM module. If the address is not
mapped into the RAM or ROM space, then the request is handled by the instruction cache
in the normal fashion.
5.1.5 Memory Reference Attributes
For every memory reference generated by the processor or the debug module, a set of
“effective attributes” is determined based on the address and the Access Control Registers
(ACR0, ACR1). This set of attributes includes the cacheable/non-cacheable definition, the
precise/imprecise handling of operand writes and the write-protect capability.
In particular, each address is compared to the values programmed in the Access Control
Registers. If the address matches one of the ACR values, the access attributes from that
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ACR are applied to the reference. If the address does not match either ACR, then the default
value defined in the Cache Control Register (CACR) is used. The specific algorithm is:
if (address = ACR0_address including mask)
Effective Attributes = ACR0 attributes
else if (address = ACR1_address including mask)
Effective Attributes = ACR1 attributes
else Effective Attributes = CACR default attributes
5.1.6 Cache Coherency and Invalidation
The instruction cache does not monitor processor data references for accesses to cached
instructions. Therefore it is necessary for software to maintain cache coherence by
invalidating the appropriate cache entries after modifying code segments.
The cache invalidation can be performed in two ways:
1. The assertion of bit 24 in the Cache Control Register, via a CPU space write, forces the
entire instruction cache to be marked as invalid. The invalidation operation requires N (N =
# of lines) cycles since the cache sequences through the entire tag array clearing a single
location (the valid location) each cycle. Any subsequent instruction fetch accesses are
postponed until the invalidation sequence is complete; i.e. the processor can continue
running as long as it does not try and fetch from the instruction cache. If the instruction cache
is accessed, processing halts and waits for the invalidation to complete. The CACR can be
loaded to not turn on the instruction cache to let processing continue unblocked.
2. The privileged CPUSHL instruction can be used to invalidate a single cache line. When
this instruction is executed, the cache entry defined by bits [X:4] of the source address
register in invalidated, provided bit 28 of the CACR is cleared.
These invalidation operations may be initiated from the processor or the debug module.
5.1.7 Reset
A hardware reset clears the CACR disabling the instruction cache. The contents of the tag
array are not affected by the reset. Accordingly, the system start-up code must explicitly
perform a cache invalidation by setting CACR[24] before the cache may be enabled.
5.1.8 Line Fill Buffer and Cache Miss Fetch Algorithm
As discussed in Section 5.1.1, the instruction cache hardware includes a 16-byte line fill
buffer for providing temporary storage for the last fetched instruction.
With the cache enabled as defined by CACR[31], a cacheable instruction fetch that misses
in both the tag memory and the line-fill buffer generates an external fetch. The size of the
external fetch is determined by the value contained in the 2-bit CLNF field of the CACR, and
the miss address. Table 5-3 shows the relationship between the CLNF bits, the miss
address and the size of the external fetch:
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Table 5-3. Initial Fetch Size Based on Miss Address & CLNF
MISS ADDRESS [3:2] (LONGWORD ADDRESS BITS)
CLNF[1:0]
00
01
10
Line
11
00
01
1X
Line
Line
Line
Line
Line
Line
Longword
Longword
Line
Longword
Line
Depending on the runtime characteristics of the application and the memory response
speed, overall performance may be increased by programming the CLNF bits to values {00,
01}.
For all cases of a line-sized fetch, the critical longword defined by bits [3:2] of the miss
address is accessed first, followed by the remaining three longwords which are accessed by
incrementing the longword address in a modulo-16 fashion as shown below:
if miss address[3:2] = 00
fetch sequence = {$0, $4, $8, $C}
if miss address[3:2] = 01
fetch sequence = {$4, $8, $C, $0}
if miss address[3:2] = 10
fetch sequence = {$8, $C, $0, $4}
if miss address[3:2] = 11
fetch sequence = {$C, $0, $4, $8}
Once an external fetch has been initiated and the data loaded into the line-fill buffer, the
instruction cache maintains a special most-recently-used indicator which tracks the contents
of the fill buffer versus its corresponding cache location. At the time of the miss, the
hardware indicator is set, marking the fill buffer as “most recently used”. If a subsequent
access to the cache location defined by bits [X:4] of the fill buffer address occurs, the data
in the cache memory array is now most-recently-used, so the hardware indicator is cleared.
In all cases, the indicator defines whether the contents of the line-fill buffer or the memory
data array are most-recently-used. At the time of the next cache miss, the contents of the
line-fill buffer are written into the memory array if the entire line is present, and the fill buffer
data is still most-recently-used compared to the memory array. Only a complete line can be
transferred to the icache array (the array only has one valid bit while the line-fill buffer has a
valid bit per longword). This transfer can only occur if the icache is not locked or frozen. This
write takes four cycles with ICH_ADDR[3:2] incrementing each cycle. Generally, when a
fetch misses the cache, the previously fetched instruction line in the line-fill buffer is written
to the cache while the master bus is running a fetch cycle.
The fill buffer can also be utilized as temporary storage for line-sized bursts of non-
cacheable references under control of CACR [10]. With this bit set, a non-cacheable
instruction fetch is processed as defined by Table 5-3. For this condition, the fill buffer is
loaded and subsequent references can “hit” in the buffer, but the data is never loaded into
the memory array.
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Line fills begin with the longword containing the requested instruction and wrap around, as
needed, to complete the full 16-byte line request. Noncachable accesses can still result in
line requests to the master bus because they are buffered in the cache line-fill buffer, but
they are not copied into the cache. Requests which result in a longword fetch will not be
written to the cache.
The relationship between CACR bits 31 and 10, and the type of instruction fetch is shown
below.
Table 5-4. Instruction Cache Operation as Defined by CACR[31, 10]
CACR CACR
TYPE OF INST
FETCH
DESCRIPTION
[31]
[10]
0
0
-
Instruction Cache is completely disabled;
All fetches are word, longword in size.
0
1
1
1
1
-
-
All fetches are treated as non-cacheable and loaded
into the line-fill buffer as defined by Table 5-3.
Cacheable Fetch size is defined by Table 5-3, and contents of the
line fill buffer can be written into the memory array.
0
1
Non-cacheable All fetches are longword in size, and not loaded into the
line-fill buffer.
Non-cacheable Fetch size is defined by Table 5-3, and loaded into the
line-fill buffer, but are never written into the memory
array.
5.1.9 Instruction Cache Programming Model
The operation of the instruction cache and local bus controller are defined by three
supervisor registers: the Cache Control Register (CACR) and two Access Control Registers
(ACR0, ACR1). All three registers may be written from the processor using the privileged
MOVEC instruction. Additionally, the registers may be accessed from the debug module.
From the debug module, the registers may be read or written. In all cases, undefined bits in
a register are reserved. These bits should be written as zeroes, and return zeroes when read
from the debug module.
5.1.10 Cacheability
Cacheability of instruction accesses is controlled by either the access control registers
ACR0 and ACR1, for accesses matching the address ranges defined by these registers, or
by the default cache mode bits in the CACR for all other accesses. Only instruction fetches
are cached (i.e. code space accesses.)
5.1.11 Cache Control Register (CACR)
The operation of the instruction cache is controlled by the Cache Control Register (CACR).
The CACR also provides a set of default memory access attributes used when a reference
address does not map into the space defined by the Access Control Registers.
The CACR is accessed as control register $002 using the privileged MOVEC instruction.
This instruction provides write-only access to this register from the processor. Additionally,
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the CACR register may be accessed from the debug module in a similar manner. The entire
register is cleared by a hardware reset.
BITS
31
30
29
28
27
26
25
24
CINV
0
23
18
17
16
FIELD CENB
-
-
-
CPSH CFRZ
-
-
-
-
-
-
PARK
RESET
R/W
0
0
0
0
W
W
W
W
W
BITS
15
11
10
9
8
7
6
5
4
2
1
0
DBW
E
FIELD
-
CBEN DCM
-
DWP
-
CLNF
RESET
R/W
-
-
0
0
0
-
-
0
-
-
0
W
W
W
W
W
Cache Control Register (CACR)
Field Definitions:
5.1.11.1 CENB: CACR[31]—CACHE ENABLE.
0 = Cache disabled
1 = Cache enabled
The memory array of the instruction cache is enabled only if CENB is asserted. If
ICH_SZ[2:0] is set to zero, this bit is set to zero and the ICACHE module is disabled. Any
attempt to set the CENB bit is disabled when ICH_SZ[2:0] is set to zero.
5.1.11.2 CPSH: CACR[28] - CPUSH DISABLE INVALIDATE.
0 = Enable Invalidation
1 = Disable Invalidation
When the privileged CPUSHL instruction is executed, the cache entry defined by bits [X:4]
of the address is invalidated if CPSH = 0. If CPSH = 1, no operation is performed.
5.1.11.3 CFRZ: CACR[27]—CACHE FREEZE.
0 = Normal operation
1 = Freeze valid cache lines
Setting this bit effectively freezes the contents of the cache. Line fetches may still be initiated
and loaded into the line fill buffer, but a valid cache entry is never overwritten. If a given
cache location is invalid, the contents of the line-fill buffer may be written into the memory
array while CFRZ is asserted.
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5.1.11.4 CINV: CACR[24]—CACHE INVALIDATE.
0 = No operation
1 = Invalidate all cache lines
Setting this bit forces the cache to invalidate each tag array entry. The invalidation process
requires N (N = #lines) machine cycles, with a single cache entry cleared per machine cycle.
The state of this bit is always read as a zero. After a hardware reset, the cache must be
invalidated before it is enabled.
5.1.11.5 PARK: CACR[17:16]—OPTIONAL EXTERNAL ARBITER CONTROL.
This field can be used to drive an external master arbiter control module via the MARBC[1:0]
signals. Otherwise, these bits can use used as general purpose output bits. Refer to Section
3.10 Master Bus Arbitration. If an external master arbiter module is not used, the
MARBC[1:0] signals may be used as general purpose control signals.
5.1.11.6 CBEN:CACR[10]—CACHE ENABLE NON-CACHEABLE INSTRUCTION
BURSTING.
0 = Disable burst fetches on non-cacheable accesses
1 = Enable burst fetches on non-cacheable accesses
Setting this bit allows the line-fill buffer to be loaded with burst transfers under control of
CLNF[1:0] for non-cacheable accesses. Non-cacheable accesses are never written into the
memory array. CBEN in conjunction with CACR[31], CENB, determines the line buffer and
ICACHE array status. See Table 5-5 for guidance in setting CACR[10].
Table 5-5. CACR[31] and CACR[10] CONFIGURATION
CACR[31]
CACR[10]
ICACHE/LINE FILL BUFFER CONFIGURATION
ICACHE disabled, LINE FILL BUFFER disabled
ICACHE disabled, LINE FILL BUFFER enabled
0
0
1
0
1
0
ICACHE enabled, LINE FILL BUFFER enabled on
cachable accesses
1
1
ICACHE enabled, LINE FILL BUFFER enabled, but
get the line-fill buffer even on non-cacheable accesses
5.1.11.7 DCM: CACR[9]—DEFAULT INSTRUCTION FETCH CACHE MODE.
0 = Caching enabled
1 = Caching disabled
This bit defines the default cache mode: 0 is cacheable, 1 is non-cacheable. For more
information on the selection of the effective memory attributes, see Section 5.1.5.
5.1.11.8 DBWE:CACR[8]—DEFAULT BUFFERED WRITE ENABLE.
0 = Disable buffered writes
1 = Enable buffered writes
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This bit defines the default value for enabling buffered writes. If DBWE = 0, the termination
of an operand write cycle on the processor’s local bus is delayed until the external bus cycle
is completed. If DBWE = 1, the write cycle on the local bus in terminated immediately, and
the operation buffered in the bus controller. In this mode, operand write cycles are effectively
decoupled between the processor’s local bus and the external bus.
Generally, the enabling of buffered writes provides higher system performance, but recovery
from access errors may be more difficult. For the ColdFire CPU, the reporting of access
errors on operand writes is always imprecise, and enabling buffered writes simply decouples
the write instruction from the signaling of the fault even more.
5.1.11.9 DWP: CACR[5]—DEFAULT WRITE PROTECTION.
0 = Read and write access permitted
1 = Only read access permitted
The DWP bit defines the default write-protection attribute. If the effective memory attributes
for a given access select the DWP bit, then any attempted write with this bit set is terminated
with an access error.
5.1.11.10 CLNF:CACR[1:0]—CACHE LINE FILL.
This two-bit field determines the size of the instruction fetch memory transfer based on
various CACR bits. See Section 5.1.8 for additional information.
The encoding is shown in Table 5-6.
Table 5-6. External Fetch Size Based on Miss Address & CLNF
MISS ADDRESS[3:2]
CLNF[1:0]
00
01
10
11
00
01
1X
Line
Line
Line
Line
Line
Line
Line
Longword
Longword
Line
Longword
Line
5.2 ACCESS CONTROL REGISTERS (ACR0, ACR1)
The two access Control Registers (ACR0, ACR1) provide a definition of memory reference
attributes for two memory regions (one per ACR). This set of effective attributes is defined
for every memory reference using the ACRs or the set of default attributes contained in the
CACR. The ACRs are examined for every memory reference that is NOT mapped to the
RAM or ROM module.
The ACRs are accessed as control registers $004 and $005 using the privileged MOVEC
instruction (ACR0 = $004, ACR1 = $005). This instruction provides write-only access to
these registers from the processor. Additionally, the ACRs may be accessed from the debug
module in a similar manner. Each ACR is disabled by a hardware reset.
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5.2.1 ACR Programming Model
The ACRs are accessible in supervisor mode using the MOVEC instruction to access control
register $004 for ACR0 and $005 for ACR1. All undefined bits are reserved and should
always be written as zero. A hardware reset clears all bits in the ACRs.
BITS
FIELD
RESET
R/W
31
24
23
16
AB
0
AM
0
W
W
BITS
FIELD
RESET
R/W
15
EN
0
14
13
12
8
7
6
5
4
3
2
WP
0
1
0
SM
0
-
-
-
ENIB CM BUFW
-
-
-
-
-
-
0
0
0
W
W
W
W
W
W
Access Control Register (ACR0, ACR1)
Field Definitions:
5.2.1.1 AB: ACR[31:24]—ADDRESS BASE [31:24].
This 8-bit field is compared to address bits [31:24] from the processor’s local bus, under
control of the ACR address mask. If the address matches, the attributes for the memory
reference are sourced from the given ACR.
5.2.1.2 AM: ACR [23:16]—ADDRESS MASK [23:16].
This 8-bit field masks comparison of the access address with the ACR address base bits.
Setting an AM bit ignores the comparison of the corresponding address base bits.
5.2.1.3 EN: ACR [15]—ENABLE .
0 = ACR disabled
1 = ACR enabled
The EN bit defines the ACR enable. This bit is cleared by hardware reset, disabling the ACR.
5.2.1.4 SM: ACR [14:13]—SUPERVISOR MODE .
00 = Match if user mode
01 = Match if supervisor mode
1x = Match always; ignore user/supervisor mode
This two-bit field allows the given ACR to be applied to references based on operating
privilege mode of the ColdFire processor. The field allows use of the ACR for user-
references only, supervisor-references only, or all accesses.
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5.2.1.5 CM: ACR [6]—CACHE MODE.
0 = Caching enabled
1 = Caching disabled
This bit defines the cache mode: 0 is cacheable, 1 is non-cacheable.
5.2.1.6 BWE: ACR [5]—BUFFERED WRITES.
0 = Disable buffered writes
1 = Enable buffered writes
This bit defines the value for enabling buffered writes. If BWE = 0, the termination of an
operand write cycle on the processor’s local bus is delayed until the external bus cycle is
completed. If BWE = 1, the write cycle on the local bus is terminated immediately, and the
operation buffered in the bus controller. In this mode, operand write cycles are effectively
decoupled between the processor’s local bus and the external bus.
Generally, the enabling of buffered writes provides higher system performance, but recovery
from access errors may be more difficult. For the ColdFire CPU, the reporting of access
errors on operand writes is always imprecise, and enabling buffered writes simply decouples
the write instruction from the signaling of the fault even more.
5.2.1.7 WP: ACR [2]—WRITE PROTECT.
0 = Read and write accesses permitted
1 = Only read accesses permitted
The WP bit defines the write-protection attribute. If the effective memory attributes for a
given access select the WP bit, then any attempted write with this bit set is terminated with
an access error.
5.3 ROM MODULE
The ColdFire2/2M has a dedicated bus to support an integrated ROM with the following
features:
• 0 - 32 Kbytes ROM, organized by ROM size/4 x 32 bits
• ROM byte-size programmed with ROM_SZ[2:0] static signals
• Single-cycle access
• Physically located on processor’s high-speed bus
• Byte, word, longword addressable
• Memory-mapping defined by user
• Configurable at reset as boot memory
The ROM module provides a general-purpose memory block that the ColdFire2/2M can
access in a single clock, and can store either code or data structures. The ROM can be
programmed to function as a boot memory; this configurable option is available at reset time.
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The ROM size is specified via the ROM_SZ[2:0] pins which are static signals that need to
stay valid for all operation. Only the ColdFire2/2M can access the ROM module.
The ColdFire2/2M issues the instruction fetches in parallel to all K-Bus memories. Fetches
from the ROM module are not cached because they require only one clock cycle to
complete. Two ROMs are used to lower power consumption by only driving the required
portions of the data bus.
5.3.1 ROM Signal Description
These signals interface the ColdFire2/2M to two integrated ROMs. Figure 5-2 illustrates an
8 Kbyte configuration. All ColdFire2/2M signals are unidirectional and synchronous.
CPU Core
ROM 0
A[10:0]
[12:2]
[31:0]
ROM_ADDR[14:2]
[31:16]
[0]
ROM_DO[31:0]
ROM_ENB[1:0]
DO[15:0]
ROMENB
ROM 1
A[10:0]
[2:0]
ROM_VLD Size
[15:0]
[1]
DO[15:0]
ROMENB
Figure 5-2. Example 8 Kbyte ROM Interface Diagram
5.3.1.1 ROM ADDRESS BUS (ROM_ADDR[14:2]). These output signals provide the
address of the current bus cycle to the integrated ROMs. This bus should be connected to
the address bus (A) of the compiled ROMs. The number of valid address signals depends
on the total ROM size as shown in Table 5-7.
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Table 5-7. Valid ROM Address Bits
TOTAL ROM SIZEVALID ROM_ADDR BITS
0
None
512
1 K
2 K
4 K
8 K
16K
32K
ROM_ADDR[8:2]
ROM_ADDR[9:2]
ROM_ADDR[10:2]
ROM_ADDR[11:2]
ROM_ADDR[12:2]
ROM_ADDR[13:2]
ROM_ADDR[14:2]
5.3.1.2 ROM DATA OUTPUT BUS (ROM_DO[31:0]). These input signals provide the
read data path from the integrated ROMs to the ColdFire2/2M. The data bus is 32-bits wide
and can transfer 8, 16, or 32 bits of data per bus transfer. During a line transfer, the data
lines are time-multiplexed across multiple cycles to carry 128 bits. This bus should be
connected to the data outputs (DO) of the compiled ROMs.
5.3.1.3 ROM ENABLE (ROM_ENB[1:0]). These active-low, output signals indicate the
ROMs are currently selected to drive the ROM_DO[31:0] bus. These signals should be
connected individually to the enable signal (ROMENB) signal of the compiled ROMs. Both
are asserted for 32-bit accesses. ROM_ENB[0] connects to the MSW while ROM_ENB[1]
connects to the LSW.
5.3.1.4 ROM SIZE (ROM_SZ[2:0]). These static inputs specify the size of the compiled
ROMs connected to the ColdFire2/2M. These pins need to stay valid during all operation.
Table 5-8 lists the possible ROM configurations. If the ROM_SZ pins are zero, the ROM
cannot be enabled via a CPU space write to ROMBAR. Therefore, if the ROM is enabled
while the ROM_SZ pins are at zero, the processor behaves as if no ROM module existed.
Table 5-8. ROM Configuration Encoding
1
TOTAL ROM SIZE
ADDRESS
DATA
(BITS)
-
ROM_SZ[2:0]
(BYTES)
None
512
(BITS)
000
001
010
011
100
101
110
-
7
2 @ 16
2 @ 16
2 @ 16
2 @ 16
2 @ 16
2 @ 16
1 K
8
2 K
9
4 K
10
11
12
8 K
2
16K
2
111
13
2 @ 16
32K
NOTES: 1. 2 ROMs, each 16-bits wide
2. 16K and 32K ROMs may require a reduced operating frequency.
5.3.1.5 ROM VALID (ROM_VLD). This active-high input signal determines if the ROM
module should be active immediately after a hard reset. Thus, if asserted, the first fetches
($0, $4) go to ROM instead of external memory. ROM_VLD controls the reset value of the
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ROM base address register (i.e. the ROM must be based at $0000 if ROM_VLD is
asserted).
5.3.2 ROM Programming Model
The configuration information in the ROM base address register (ROMBAR) controls the
ROM module operation. The ROMBAR is accessible in supervisor mode as control register
$C00 using the MOVEC instruction. All undefined bits are reserved and should always be
written as zero. A hardware reset clears only the valid bit if ROM_VLD is negated. If
ROM_VLD is asserted, ROMBAR is reset to $0121. This activates the ROM with a starting
address of $0000 and all address spaces, except the CPU space, are allowed. This is shown
below where the reset values in parenthesis are valid if ROM_VLD is asserted during a
reset.
BITS
FIELD
RESET
R/W
31
16
BA
-(0)
W
BITS
FIELD
RESET
R/W
15
9
8
7
6
5
1
0
V
BA
-(0)
W
WP
-(1)
W
-
-
-
AS
-
0(1)
W
W
NOTE: The reset values in parenthesis are valid if the ROM_VLD signal is asserted during reset.
ROM Base Address Register (ROMBAR)
Field Definitions:
5.3.2.1 BA: ROMBAR[31:9]—BASE ADDRESS.
Defines the base address for the ROM module address range. The number of valid base
address bits in this field is a function of the ROM size as shown in Table 5-9. The base
address is reset to $0 if ROM_VLD is asserted during reset.
Table 5-9. Valid ROM Base Address Bits
ROM SIZE
512
VALID BA BITS
BA[31:9]
1 K
BA[31:10]
BA[31:11]
BA[31:12]
BA[31:13]
BA[31:14]
BA[31:15]
2 K
4 K
8 K
16K
32K
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5.3.2.2 WP: ROMBAR[8]—WRITE PROTECT.
This bit is reserved for future use. This bit can be used for debug purposes; i.e. it could set
a trip point when a write to ROM occurred.
0 = No effect
1 = An attempted write access will generate an access error exception in the processor.
5.3.2.3 AS ROMBAR[5:1]—ADDRESS SPACE MASKS.
This five-bit field, specified by ROMBAR[5:1], allows certain types of accesses to be
“masked” or inhibited, from accessing the RAM module. The mask bits are defined as:
AS5 - Mask CPU Space and Interrupt Acknowledge Accesses
AS4 - Mask Supervisor Code Accesses
AS3 - Mask Supervisor Data Accesses
AS2 - Mask User Code Accesses
AS1 - Mask User Data Accesses
If a given mask bit is set, then references of that type are NOT allowed to access the ROM
module.
If ASn = 0, then accesses of the given type are allowed by the ROM.
If ASn = 1, then accesses of the given type are not allowed by the ROM. If an access is made
to a space that is masked, it simply becomes mapped to the next valid space.
5.3.2.4 V: ROMBAR [0]—VALID.
The valid bit is specified by ROMBAR[0]. This bit is cleared by a hardware reset. When set,
this bit enables the ROM module, otherwise the module is disabled.
If ROM_SZ is set to zero, this bit is set to zero and the ROM module is disabled. Any attempt
to set the valid bit is disabled when ROM_SZ is set to zero.
5.3.3 ROM INITIALIZATION / ROM BOOT
After a hardware reset, the contents of the ROMBAR depend upon the ROM_VLD signal
polarity and the ROM_SZ[2:0] configuration. If ROM_SZ[2:0] = 0, the valid bit is held
cleared, even if a write is attempted during a load to ROMBAR.
ROM_VLD determines if the ROM module should be active immediately after a hard reset.
Thus, if ROM_VLD is asserted, the first fetches ($0, $4) go to ROM instead of external
memory. Note, if ROM_VLD is asserted, ROM_SZ cannot be set to zero. ROM_VLD
controls the reset value of the ROM base address register (i.e. the ROM must be based at
$0000 if ROM_VLD is asserted).
To map the ROMBAR, a load to the ROMBAR mapping the ROM module to the desired
location within the address space, must be performed.
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5.3.4 Power Management
As noted previously, depending upon the configuration defined by the ROMBAR, instruction
fetch accesses may be sent to the ROM module and the I-Cache simultaneously. If the
access is mapped to the ROM module, it sources the read data and the I-Cache access is
discarded. If the ROM is used only for data operands, power dissipation can be lowered by
asserting the ASn bits associated with instruction fetches. Additionally, if the ROM contains
only instructions, power dissipation can be reduced by masking operand accesses.
Consider the following examples of typical ROMBAR settings:
Data contained in ROM
ROMBAR[7:0]
Only code
Only data
Both code and data
$2B
$35
$21
5.4 RAM MODULE
The ColdFire2/2M has a dedicated bus to support an integrated RAM with the following
features:
• 0 - 32 Kbytes RAM, organized by RAM byte size/4 x 32 bits
• RAM byte-size programmed with RAM_SZ[2:0] static signals
• Single-cycle access
• Physically located on processor’s high-speed local bus
• Byte, word, longword address capability
• Memory mapping defined by user
5.4.1 RAM Operation
The RAM module provides a general-purpose memory block that the ColdFire2/2M can
access in a single cycle. The RAM size is specified via the RAM_SZ[2:0] pins which are
static signals that need to stay valid for all operation. The location of the memory block may
be specified to any 0-modulo-[ICACHE byte size] address within the four gigabyte address
space. The memory is ideal for storing critical code or data structures, or for use as the
system stack. Since the RAM module physically is connected to the processor’s high-speed
local bus, it can service CPU-initiated accesses, or memory referencing commands from the
debug module.
Depending on configuration information, instruction fetches can be sent to both the
instruction cache and the RAM block simultaneously. If the instruction fetch address is
mapped into the region defined by the RAM, the RAM provides data back to the processor,
and the I-cache data is discarded. Accesses from the RAM module are not cached.
Generally, the RAM is loaded by copying a hex image from another memory region into the
RAM address space. This copy function can be performed by the processor during
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initialization, or can be performed by an emulator during system debug. The emulator
approach uses the BDM serial communication channel to download the hex image from a
host machine into the RAM directly.
5.4.2 RAM Signal Description
These signals interface the ColdFire2/2M to the four integrated arrays that comprise the
RAM. Figure 5-3 illustrates an 8 Kbyte configuration. All ColdFire2/2M signals are
unidirectional and synchronous.
CPU CORE
RAM 0
A[10:0]
[12:2]
RAM_ADDR[14:2]
CSB
RAM_CSB
[31:24]
[31:0]
[31:0]
[3:0]
RAM_DI[31:0]
DBI[7:0]
DBO[7:0]
ST
[31:24]
[0]
RAM_DO[31:0]
RAM_ST[3:0]
[3:0]
[0]
RAM_RWB[3:0]
RWB
RAM_SZ[2:0]
SIZE
RAM 3
A[10:0]
CSB
[7:0]
[7:0]
[3]
DBI[7:0]
DBO[7:0]
ST
[3]
RWB
Figure 5-3. Example 8 Kbyte RAM Interface Diagram
5.4.2.1 RAM ADDRESS BUS (RAM_ADDR[14:2]).
These registered output signals provide the address of the current bus cycle to the
integrated RAMs. This bus should be connected to the address bus (A) of the four compiled
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RAMs. The number of valid address signals depends on the total RAM size as shown in
Table 5-10.
Table 5-10. Valid RAM Address Bits
TOTAL RAM SIZE VALID RAM_ADDR BITS
0
None
512
1 K
2 K
4 K
8 K
16K
32K
RAM_ADDR[8:2]
RAM_ADDR[9:2]
RAM_ADDR[10:2]
RAM_ADDR[11:2]
RAM_ADDR[12:2]
RAM_ADDR[13:2]
RAM_ADDR[14:2]
5.4.2.2 RAM CHIP-SELECT (RAM_CSB). This active-low output signal indicates the
RAMs are currently selected to perform a data transfer with the ColdFire2/2M. This signal
should be connected to the chip-select (CSB) signal of the four compiled RAMs.
5.4.2.3 RAM DATA INPUT BUS (RAM_DI[31:0]). These output signals provide the write
data path between the ColdFire2/2M and the integrated RAM. The data bus is 32-bits wide
and can transfer 8, 16, or 32 bits of data per bus transfer. During a line transfer, the data
lines are time-multiplexed across multiple cycles to carry 128 bits. This bus should be
connected to the data inputs (DBI) of the four compiled RAMs. If only one byte is being
written, the byte will be replicated on all 4 lines; likewise a word will be replicated in both
word positions.
5.4.2.4 RAM DATA OUTPUT BUS (RAM_DO[31:0]). These input signals provide the read
data path between the integrated RAM and the ColdFire2/2M. The data bus is 32-bits wide
and can transfer 8, 16 or 32 bits of data per bus transfer. During a line transfer, the data lines
are time-multiplexed across multiple cycles to carry 128 bits. This bus should be connected
to the data outputs (DBO) of the four compiled RAMs.
5.4.2.5 RAM SIZE (RAM_SZ[2:0]). These static inputs specify the size of the compiled
RAMs connected to the ColdFire2/2M. These pins need to stay valid during all operation. If
the RAM_SZ pins are zero, the RAM cannot be enabled via a CPU space write to RAMBAR.
Therefore if the RAM is enabled while the RAM_SZ pins are at zero, the processor behaves
as if no RAM module existed.
Table 5-11 lists the possible RAM configurations.
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Table 5-11. RAM Configuration Encoding
1
TOTAL RAM SIZE
ADDRESS
DATA
RAM_SZ[2:0]
(BYTES)
0
(BITS)
(BITS)
-
000
001
010
011
100
101
110
-
512
1 K
7
4@8
4@8
4@8
4@8
4@8
4@8
8
2 K
9
4 K
10
11
12
8 K
2
16K
2
111
13
4@8
32K
NOTES: 1. 4 RAMs, each 8-bits wide
2. 16K and 32K RAMs may require a reduced operating
frequency.
5.4.2.6 RAM STROBE (RAM_ST[3:0]). These output signals initiate a read or write cycle
to the integrated RAMs on a low-to-high transition. These signals should be connected
individually to the strobe input (ST) signals of the four compiled RAMs. The ST[0] signal
connects to the high-order byte and ST[3] connects to the low-order byte.
5.4.2.7 RAM READ/WRITE (RAM_RWB[3:0]). These output signals indicate the direction
of the data transfer to the integrated RAMs. A high level indicates a read cycle and a low
level indicates a write cycle. They should be connected individually to the read/write (RWB)
signal of the four compiled RAMs. Like RAM_ST[3:0], the RAM_RWB[3] signal connects to
the high-order byte and RAM_ST[0] connects to the low-order byte.
5.4.3 RAM Programming Model
The configuration information in the RAM base address register (RAMBAR) controls the
operation of the RAM module. The RAMBAR is accessed as control register $C04 using the
privileged MOVEC instruction. The MOVEC instruction provides write-only access to this
register. Additionally, the RAMBAR register may be accessed from the debug module in a
similar manner. From the debug module, the register may be read or written. All undefined
bits are reserved. These bits should be written as zeroes, and return zeroes when read from
the debug module. Only the valid bit is cleared by a hardware reset.
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5.4.4 RAM Base Address Register
W
BITS
FIELD
RESET
R/W
31
16
BA
-
W
BITS
FIELD
RESET
R/W
15
9
8
WP
-
7
6
5
1
0
V
0
BA
-
-
-
-
AS
-
W
W
W
W
RAM Base Address Register (RAMBAR)
Field Definitions:
5.4.4.1 BA: RAMBAR [31:9]—BASE ADDRESS.
Defines the base address for the RAM module address range. The number of valid base
address bits in this field are a function of the RAM size as shown in Table 5-12. By
programming this field, the RAM may be located anywhere within the four gigabyte address
space of ColdFire.
Table 5-12. Valid RAM Base Address Bits
RAM BYTE SIZE
VALID BA BITS
BA[31:9]
512
1 K
2 K
4 K
8 K
16K
32K
BA[31:10]
BA[31:11]
BA[31:12]
BA[31:13]
BA[31:14]
BA[31:15]
5.4.4.2 WP: RAMBAR [8]—WRITE PROTECT.
0 = RAM module supports read and write references
1 = RAM module supports only read accesses.
The write protect field is defined by RAMBAR [8]. If set, this bit allows only read
accesses to the RAM. Any attempted write access will generate an access error
exception in the processor.
If cleared, the RAM supports read and write references.
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5.4.4.3 AS: RAMBAR [5:1]—ADDRESS SPACE MASKS.
This five bit field, specified by RAMBAR [5:1], allows certain types of accesses to be
“masked”, or inhibited, from accessing the RAM module. The mask bits are defined as:
AS5 - Mask CPU Space and Interrupt Acknowledge Accesses
AS4 - Mask Supervisor Code Accesses
AS3 - Mask Supervisor Data Accesses
AS2 - Mask User Code Accesses
AS1 - Mask User Data Accesses
If a given mask bit is set, then references of that type are NOT allowed to access the RAM
module. These bits are useful for power management as detailed in section 5.4.6.
If ASn = 0, then accesses of the given type are allowed by the RAM.
If ASn = 1, then accesses of the given type are not allowed by the RAM. If an access is made
to a space that is masked, it simply becomes mapped to the next valid space.
5.4.4.4 V: RAMBAR [0]—VALID.
This bit indicates when the contents of the RAMBAR are valid. The base address value is
not used, and the RAM module is not accessible until the V-bit is set. An external bus cycle
is generated if the base address field matches the internal core address, and the V-bit is
cleared.
0 = Contents of RAMBAR are not valid
1 = Contents of RAMBAR are valid
The valid bit is specified by RAMBAR [0]. This bit is cleared by a hardware reset. When set,
this bit enables the RAM module, otherwise the module is disabled.
The mapping of a given access into the RAM used the following algorithm to determine if
the access “hits” in the memory:
if (RAMBAR[0] = 1)
if (requested address [31:9]* = RAMBAR[31:9]*
if (ASn of the requested type = 0)
Access is mapped to the RAM module
if (access = read)
Read the RAM and return the data
if (access = write)
if (RAMBAR[8] = 0)
Write the data into the RAM
else Signal a write-protect access error
* See Table 5-10 for address bit map pertaining to RAM sizes.
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If RAM_SZ is set to zero, this bit is set to zero, and the RAM module is disabled. Any attempt
to set the valid bit is disabled when RAM_SZ is set to zero.
5.4.5 RAM Initialization
After a hardware reset, the contents of the RAM module are undefined. The valid bit of the
RAMBAR is cleared, disabling the module. If the RAM needs to be initialized with
instructions or data, the following steps should be performed:
1.
Load the RAMBAR mapping the RAM module to the desired location within the
address space.
2.
Read the source data and write it to the RAM. There are various instructions to
support this function, including memory-to-memory move instructions, or the
MOVEM opcode. The MOVEM instruction is optimized to generate line-sized burst
fetches on 0-modulo-16 addresses, so this opcode generally provides maximum
performance.
3.
After the data has been loaded into the RAM, it may be appropriate to load a revised
value into the RAMBAR with a new set of “attributes”. These attributes consist of the
write-protect and address space mask fields.
These initialization functions can be performed by the ColdFire processor, or from an
external emulator using the debug module.
5.4.6 Power Management
As noted previously, depending upon the configuration defined by the RAMBAR, instruction
fetch accesses may be sent to the RAM module and the I-Cache simultaneously. If the
access is mapped to the RAM module, it sources the read data and the I-Cache access is
discarded. If the RAM is used only for data operands, power dissipation can be lowered by
asserting the ASn bits associated with instruction fetches. Additionally, if the RAM contains
only instructions, power dissipation can be reduced by masking operand accesses.
Consider the following examples of typical RAMBAR settings:
Data contained in RAM
RAMBAR[7:0]
Only code
Only data
Both code and data
$2B
$35
$21
5.5 INTERACTIONS BETWEEN KBUS MEMORIES
Depending on configuration information, instruction fetches and operand accesses may be
sent to all of the K-Bus memories (i.e. RAM, ROM, and ICACHE) simultaneously. There
needs to be consistency between the ACRs and the default modes defined by CACR
(CACR[9], CACR[8], and CACR[5]).
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If the access address is mapped into the region defined by the RAM (and this region is not
masked), the RAM provides the data back to the processor, and the I-CACHE data
discarded. Accesses from the RAM module are not cached. The ROM behaves similarly.
The RAM has priority over the ROM. The full priority scheme is as follows:
if (RAM “hits”)
RAM supplies data to the processor
else if (ROM “hits”)
ROM supplies data to the processor
else if (line-fill buffer “hits”)
line-fill buffer supplies data to the processor
else if (icache “hits”)
icache supplies data to the processor
else
master bus cycle accesses to reference data from non-K-Bus memory
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SECTION 6
MULTIPLY-ACCUMULATE UNIT
This section details the hardware multiply-accumulate (MAC) support functions within the
ColdFire2M. The MAC is not present in the ColdFire2 hard macro, but is an optional high-
speed execution unit that is available within the ColdFire core environment. If the MAC is
present, it executes the integer multiplies at an accelerated speed. The MAC unit is
designed to provide a common set of DSP operations and to enhance the current multiply
instructions in the ColdFire architecture.
The MAC unit provides functionality in three related areas:
• Faster signed and unsigned integer multiplies
• New multiply-accumulate operations supporting signed and unsigned operands
• New miscellaneous register operations
Each is addressed in detail in the following sections.
6.1 INTRODUCTION
The MAC unit is designed to optimize the current ColdFire multiply instructions, MULS and
MULU, and provide additional instructions for algorithms that use multiply-accumulate
operations. As shown in Figure 6-1, these new instructions multiply two numbers, followed
by the addition/subtraction of this product to/from the value contained in the accumulator.
The product may be optionally shifted left or right one bit before the addition or subtraction
takes place. All arithmetic operations use register-based input operands, and summed
values are stored in the internal accumulator. For word operations, the upper or lower word
of each input register can be chosen as a source operand. As a result, two word operations
will require only one register load operation. Some instructions also allow a parallel load to
be performed in addition to the MAC operation.
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Multiply-Accumulate Unit
OPERAND X
OPERAND Y
X
SHIFT 0,1,-1
+/-
ACCUMULATOR
Figure 6-1. MAC Flow Diagram
The MAC module has been designed for 16-bit multiplies to optimize the die size. Word
operations require two signed or unsigned 16-bit operands and produce a 32-bit result. By
iteratively performing multiple 16-bit operations, the MAC can perform 32-bit operations.
Longword operations require two signed or unsigned 32-bit operands and produce a 32-bit
result. Because the longword operations are iteratively computed, the MAC instructions
have an effective issue rate of one clock for word operations and three clocks for longword
operations.
6.2 MAC PROGRAMMING MODEL
The MAC unit includes three new registers: a 32-bit accumulator (ACC), an 8-bit status
register (MACSR), and a 16-bit mask register (MASK).
6.2.1 Accumulator (ACC)
This is a 32-bit special purpose register used to accumulate the results of MAC operations.
The accumulator is not cleared upon reset.
6.2.2 MAC Status Register (MACSR)
The status register contains the saturation mode control bit, the negative, zero and overflow
flags, as well as the signed/unsigned operation control bit as shown in the next register.
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BITS
FIELD
RESET
R/W
7
OMC
0
6
S/U
0
5
-
4
-
3
N
2
Z
1
V
0
C
0
0
R
0
R
-
-
-
R/W
R/W
R/W
R/W
R/W
R
MAC Status Register (MACSR)
Field Definitions:
OMC[7]–Overflow Mode Control
0 = normal mode
1 = saturation mode
This bit is used to enable or disable saturation mode on overflow. This bit is cleared by
system reset. Refer to Section 6.4 Overflow Mode.
S/U[6]–Signed/Unsigned Operations
The S/U bit defines the type of multiply operations that are performed.
0 = signed numbers
1 = unsigned numbers
This bit is cleared by system reset.
N[3]–Negative
This bit is set if the most significant bit of the result is set, cleared otherwise. This bit is
affected only by MAC operations. The MULS and MULU instructions do not change this
value.
Z[2]–Zero
This bit is set if the result equals zero, otherwise, it is cleared. This bit is affected only by
MAC operations. MULS and MULU instructions do not change this value.
V[1]–Overflow
This bit is set if an arithmetic overflow occurs implying that the result cannot be represented
in 32 bits. Once set, this bit remains set until the ACC register is loaded with a new value
using the MOVE to ACC instruction, or the MACSR is explicitly loaded using the MOVE to
MACSR instruction. The MULS and MULU instructions do not change this value.
C[0]–Carry
This field is always zero and is reserved for future use.
6.2.3 Mask Register (MASK)
This is a 16-bit special purpose register used to mask the lower 16 address bits during MAC
load operations. The field definition follows.
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Multiply-Accumulate Unit
BITS
15
0
FIELD
MASK
-
RESE
T
R/W
R/W
MAC Mask Register (MASK)
Field Definitions:
MASK[15:0]–Address Mask
This field is logically ANDed with the lower 16 bits of the effective address during MAC
instructions with a register load performed using the mask addressing mode modifier.
The actions of the mask addressing mode depend on the effective addressing mode as
shown in Table 6-1.
Table 6-1. Mask Addressing Mode
EFFECTIVE ADDRESSING MODE
OUTPUT ADDRESS
An & {0xFFFF, MASK}
An
NEW AN
(An)
(An)+
-
(An +4) & {0xFFFF, MASK}
(An - 4) & {0xFFFF, MASK}
-
-(An)
(An - 4) & {0xFFFF, MASK}
(An + d16) & {0xFFFF, MASK}
(d16, An)
NOTE: {upper, lower}notationindicatesupperandlowerorderwords
When loading data into the data registers, the MASK register can be used to implement a
very efficient circular queue.
6.3 SHIFTING OPERATIONS
The MAC unit is capable of shifting a product before the result is added to or subtracted from
the accumulator (ACC). Since there is the possibility of overflowing a 32-bit product, use the
following guidelines when performing MAC instructions:
• For both word and longword unsigned operations, a zero is shifted into the product on
right shifts.
• For signed word operations, the sign bit is shifted into the product on right shifts, unless
the product is zero.
• For signed, longword operations, the sign bit is shifted into the product unless an
overflow occurs or the product is zero, in which case a zero is shifted in.
6.4 OVERFLOW MODE
When dealing with potential overflow conditions, software overhead can be minimized by
enabling hardware support for saturation arithmetic. Saturation mode is controlled by the
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OMC bit in the MACSR. In saturation mode, if a MAC instruction overflows 32 bits during the
multiply portion of an operation, the overflow bit (V) will be set in the MACSR and the
accumulator (ACC) will contain the most positive or the most negative value possible. As
seen in Table 6-2, the value depends on the signed/unsigned mode (S/U bit in the MACSR),
multiply result, and the addition/subtraction operation.
Table 6-2. Accumulator Result in Saturation Mode
MULTIPLY/
RESULT
MAC
INSTRUCTION
MAC
OPERATION
ACCUMULATOR
RESULT
SIGNED/UNSIGNED
MAC, MACL
MSAC, MSACL
MAC, MACL
Addition
Subtraction
Addition
$7FFFFFFF
$80000000
$80000000
$7FFFFFFF
$FFFFFFFF
$00000000
Positive
Negative
-
Signed
MSAC, MSACL
MAC, MACL
Subtraction
Addition
Unsigned
MSAC, MSACL
Subtraction
The overflow value will remain in the ACC until the V bit in the MACSR is cleared by loading
a new value into the ACC or MACSR.
6.5 MAC INSTRUCTION SET SUMMARY
The MAC unit in the ColdFire2M enhances the multiply operations that are currently
supported by the ColdFire2 architecture, adds new multiply-accumulate instructions, and
adds register instructions for accessing the new MAC registers. Table 6-3 below
summarizes the MAC unit instruction set. Refer to Appendix B New MAC Instructions for
details.
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Table 6-3. MAC Instruction Set Summary
INSTRUCTION OPERAND SYNTAX OPERAND SIZE
OPERATION
MULS
<ea>,Dx
16x16→ 32
32x32→ 32
<ea>× Dx→ Dx
Note:signedoperation
MULU
<ea>,Dx
16x16→ 32
32x32→ 32
<ea>× Dx→ Dx
Note:unsignedoperation
MAC
Ry,Rx,<shift>
16× 16+ 32 → 32
32 × 32+ 32 → 32
ACC+(Ry× Rx){<<1|>>1}→ ACC
ACC+(Ry× Rx){<<1|>>1}→ ACC;(<ea>{&MASK})→ Rw
ACC-(Ry× Rx){<<1|>>1}SF→ ACC
MACL
Ry,Rx,<shift>,<ea>,Rw
Ry,Rx,<shift>
16× 16+ 32 → 32
32 × 32+ 32 → 32
MSAC
32-16× 16→ 32
32-32 × 32→ 32
MSACL
Ry,Rx,<shift>,<ea>,Rw
32-16× 16→ 32
32-32 × 32→ 32
ACC-(Ry× Rx){<<1|>>1}SF→ ACC;(<ea>{&MASK})→ Rw
ACC→ Rx
MOVE from ACC
ACC,Rx
32
MOVE from
MACSR
MACSR,Rx
MACSR,CCR
32
8
MACSR→ Rx
MACSR→ CCR
MOVE from
MASK
MASK,Rx
32
MASK→ Rx
MOVE to ACC
Ry,ACC
#<data>,ACC
32
32
Ry→ ACC
#<data>→ ACC
MOVE to CCR
Dy,CCR,
#<data>,CCR
16
Dy→ CCR
#<data>→ CCR
MOVE to MACSR
MOVE to MASK
Ry,MACSR
32
Ry→ MACSR
#<data>,MACSR
#<data>→ MACSR
Ry,MASK
#<data>,MASK
32
32
Ry→ MASK
#<data>→ MASK
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SECTION 7
DEBUG SUPPORT
This section details the hardware debug support functions within the ColdFire2/2M. The
general topic of debug support has been divided into three separate areas:
• Real-Time Trace Support
• Background Debug Mode (BDM)
• Real-Time Debug Support
Each is addressed in detail in the following sections.
The logic required to support these three areas is contained in a debug module, which is
shown in the system block diagram in Figure 7-1.
COLDFIRE CPU
INTERNAL BUSES
CORE
DEBUG
MODULE
TRACE PORT BDM PORT
BKPTB
DDATA, PST DSCLK, DSI, DSO
Figure 7-1. Processor/Debug Module Interface
7.1 SIGNAL DESCRIPTION
This section describes the ColdFire2/2M signals associated with the debug module. All
ColdFire2/2M signals are unidirectional and synchronous.
7.1.1 Break Point (BKPTB)
This active-low, unidirectional input signal is used to request a manual break point. It will
cause the processor to enter a halted state after the completion of the current instruction.
This status will be reflected on the processor status (PST) outputs.
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7.1.2 Debug Data (DDATA[3:0])
These output signals display the captured processor status and break point status.
7.1.3 Development Serial Clock (DSCLK)
This input signal is used as the development serial clock for the serial interface to the Debug
Module.The maximum frequency is 1/2 the clock (CLK) frequency.
7.1.4 Development Serial Input (DSI)
This input signal provides the single-bit communication for the debug module commands.
7.1.5 Development Serial Output (DSO)
This output signal provides single-bit communication for the debug module responses.
7.1.6 Processor Status (PST[3:0])
These output signals report the processor status. Table 7-1 shows the encoding of these
signals. These signals indicate the current status of the processor pipeline and, as a result,
are not related to the current bus transfer.
.
Table 7-1. Processor Status Encoding
PST[3:0]
DEFINITION
(HEX) (BINARY)
$0
$1
$2
$3
$4
$5
$6
$7
$8
$9
$A
$B
$C
$D
$E
$F
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Continue execution
Begin execution of an instruction
Reserved
Entry into user-mode
Begin execution of PULSE orWDDATA instruction
Begin execution of taken branch
Reserved
Begin execution of RTE instruction
Begin 1-byte transfer on DDATA
Begin 2-byte transfer on DDATA
Begin 3-byte transfer on DDATA
Begin 4-byte transfer on DDATA
Exception processing†
Emulator-mode entry exception processing†
Processor is stopped, waiting for interrupt†
Processor is halted †
NOTE: †These encodings are asserted for multiple cycles.
.
7.2 REAL-TIME TRACE
In the area of debug functions, one fundamental requirement is support for real-time trace
functionality, i.e., definition of the dynamic execution path. The ColdFire2/2M solution is to
include a parallel output port providing encoded processor status and data to an external
development system. This port is partitioned into two nibbles (4 bits): one nibble allows the
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processor to transmit information concerning the execution status of the core (processor
status, PST[3:0]), while the other nibble allows operand data to be displayed (debug data,
DDATA[3:0]). The processor status timing is synchronous with the processor clock (CLK)
and may not be related to the current bus transfer. Table 7-1 shows the encoding of these
signals.
The processor status (PST) outputs can be used with an external image of the program to
completely track the dynamic execution path of the machine. The tracking of this dynamic
path is complicated by any change-of-flow operation. This is especially evident when the
branch target address is calculated based on the contents of a program visible register
(variant addressing.) For this reason, the debug data (DDATA) outputs will display the target
address of a taken branch instruction. Because the DDATA bus is only 4 bits wide, the
address is displayed a nibble at a time across multiple clock cycles.
The debug module includes two 32-bit storage elements for capturing the internal ColdFire2/
2M bus information. These two elements effectively form a FIFO buffer connecting the
internal bus to the external development system through the DDATA signals. The FIFO
buffer captures branch target addresses along with certain operand read/write data for
eventual display on the DDATA output port one nibble at a time. The execution speed of the
ColdFire2/2M is affected only when both storage elements contain valid data waiting to be
dumped onto the DDATA port. In this case, the processor core is stalled until one FIFO entry
is available. In all other cases, data output on the DDATA port does not impact execution
speed.
7.2.1 Processor Status Signal Encoding
The processor status (PST) signals are encoded to indicate a variety of conditions that are
not always visible outside of the ColdFire2/2M.
7.2.1.1 CONTINUE EXECUTION (PST = $0). Most instructions complete in a single cycle.
If an instruction requires more clock cycles, the subsequent clock cycles are indicated by
driving the PST outputs with this encoding.
7.2.1.2 BEGIN EXECUTION OF AN INSTRUCTION (PST = $1). For most instructions,
this encoding signals the first cycle of an instruction’s execution. Some instructions generate
a different unique encoding.
7.2.1.3 ENTRY INTO USER MODE (PST = $3). This encoding indicates the ColdFire2/2M
has entered user mode. This encoding is signaled after the instruction which causes the
user mode to be entered is executed (signaled with the appropriate encoding.)
7.2.1.4 BEGIN EXECUTION OF PULSE OR WDDATA INSTRUCTIONS (PST = $4). The
ColdFire2/2M instruction set architecture includes a PULSE opcode. This opcode generates
a unique PST encoding, $4, when executed. This instruction can define logic analyzer
triggers for debug and/or performance analysis. Additionally, a WDDATA instruction is
supported that allows the processor core to write any operand (byte, word, long) directly to
the DDATA port, independent of any debug module configuration. This opcode also
generates the special PST encoding, $4, when executed, but a data transfer on DDATA will
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also be indicated. The size of the transfer will depend on the format of the WDDATA
instruction.
7.2.1.5 BEGIN EXECUTION OF TAKEN BRANCH (PST = $5). This encoding is
generated whenever a taken branch is executed. The branch target may be optionally
displayed on DDATA depending on the control parameters contained in the configuration/
status register (CSR). The number of bytes of the address to be displayed is also controlled
in the CSR and indicated during the data transfer on the following clock cycle.
The bytes are always displayed in a least-significant to most-significant order. The
processor captures only those target addresses associated with taken branches using a
variant addressing mode, i.e. all JMP and JSR instructions using address register indirect
or indexed addressing modes, all RTE and RTS instructions as well as all exception vectors.
The simplest example of a branch instruction using a variant address is the compiled code
for a C language “case” statement. Typically, the evaluation of this statement uses the
variable of an expression as an index into a table of offsets, where each offset points to a
unique case within the structure. For these types of change-of-flow operations, the
ColdFire2/2M processor uses the debug pins to output a sequence of information on
successive clock cycles
1. Identify a taken branch has been executed using the PST pins ($5).
2. Using the PST pins, optionally signal the target address is to be displayed on the
DDATA pins. The encoding ($9, $A, $B) identifies the number of bytes that are
displayed.
3. The new target address is optionally available on subsequent cycles using the nibble-
wide DDATA port. The number of bytes of the target address displayed on this port is
a configurable parameter (2, 3, or 4 bytes).
Another example of a variant branch instruction would be a JMP (A0) instruction. If the CSR
was programmed to display the lower two bytes of an address, the output of the PST and
DDATA signals when this instruction executed are shown in Figure 7-2.
CLK
PST
$5
$0
$9
$0
$0
DDATA
A[3:0]
A[7:4]
A[11:8]
A[15:12]
Figure 7-2. Example PST Diagram
In the first cycle, PST is driven with a $5 indicating a taken branch with a variant address. In
the second cycle, PST is driven with a $9 indicating a two-byte address will be displayed
four bits at a time on the DDATA signals over the next four clock cycles. The remaining four
clock cycles display the lower two-bytes of the address (A0), least significant nibble to most
significant nibble. The output of the PST signals after the branch instruction completes will
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be dependent on the next instruction in the pipeline. The PST can continue with the next
instruction before the address has completely displayed on the DDATA because of the
DDATA FIFO. If the FIFO is full and the next instruction needs to display something on
DDATA, the pipeline will stall (PST = $0) until space is available in the FIFO.
7.2.1.6 BEGIN EXECUTION OF RTE INSTRUCTION (PST = $7). The unique encoding is
generated whenever the return-from-exception instruction is executed.
7.2.1.7 BEGIN DATA TRANSFER (PST = $8 - $A). These encodings indicate the number
of bytes to be displayed on the DDATA port on subsequent clock cycles. This encoding is
driven onto the PST port one machine cycle before the actual data is displayed on DDATA.
7.2.1.8 EXCEPTION PROCESSING (PST = $C). This encoding is displayed during normal
exception processing. Exceptions which enter emulation mode (debug interrupt, or optional
trace) generate a different encoding. Because this encoding defines a multicycle mode, the
PST outputs are driven with this value until exception processing is completed.
7.2.1.9 EMULATOR-MODE EXCEPTION PROCESSING (PST = $D). Exceptions which
enter emulation mode (debug interrupt, or optional trace) generate a different this encoding.
Because this encoding defines a multicycle mode, the PST outputs are driven with this value
until exception processing is completed.
7.2.1.10 PROCESSOR STOPPED (PST = $E). This encoding is generated as a result of
the STOP instruction. The ColdFire2/2M remains in the stopped state until an interrupt
occurs. Because this encoding defines a multicycle mode, the PST outputs are driven with
this value until the stopped mode is exited.
7.2.1.11 PROCESSOR HALTED (PST = $F). This encoding is generated as when the
ColdFire2/2M is halted (see Section 7.3.1 CPU Halt.) Because this encoding defines a
multicycle mode, the PST outputs are driven with this value until the halted mode is exited.
7.3 BACKGROUND DEBUG MODE (BDM)
The ColdFire2/2M supports a modified version of the background debug mode (BDM)
functionality found on Motorola’s CPU32 family of parts. BDM implements a low-level
system debugger in the microprocessor hardware. Communication with the development
system is handled via a dedicated, high-speed serial command interface (BDM port).
Unless noted otherwise, the BDM functionality provided by the ColdFire2/2M is a proper
subset of the CPU32 functionality. The main differences include the following:
• ColdFire2/2M implements the BDM controller in a dedicated hardware module.
Although some BDM operations do require the CPU to be halted (e.g. CPU register
accesses), other BDM commands such as memory accesses can be executed while
the processor is running.
• DSCLK, DSI, and DSO are treated as synchronous signals, where the inputs, DSCLK
and DSI, must meet the required input setup and hold timings, and the output, DSO, is
specified as a delay relative to the rising edge of the processor clock.
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• On CPU32 parts, the DSO signal can inform hardware that a serial transfer can start.
ColdFire clocking schemes restrict the use of this bit. Because DSO changes only when
DSCLK is high, DSO cannot be used to indicate the start of a serial transfer. The
development system should use either a free-running DSCLK or count the number of
clocks in any given transfer.
• The read/write system register commands, RSREG and WSREG, have been replaced
by read/write control register commands, RCREG and WCREG. These commands use
the register coding scheme from the MOVEC instruction.
• The read/write debug module register commands, RDMREG and WDMREG, have
been added to support debug module register accesses.
• CALL and RST commands are not supported and will generate an illegal command
response.
• Illegal command responses can be returned using the FILL and DUMP commands.
• For any command performing a byte-sized memory read operation, the upper 8 bits of
the response data are undefined. The referenced data is returned in the lower 8 bits of
the response.
• The debug module forces alignment for memory-referencing operations: long accesses
are forced to a 0-modulo-4 address; word accesses are forced to a 0-modulo-2
address. An address error response can no longer be returned.
7.3.1 CPU Halt
Although some BDM operations can occur in parallel with CPU operation, unrestricted BDM
operation requires the CPU to be halted. A number of sources can cause the CPU to halt,
including the following as shown in order of priority:
1. The occurrence of the catastrophic fault-on-fault condition automatically halts the
processor. The halt status, $F, is posted on the PST port.
2. The occurrence of a hardware breakpoint can be configured to generate a pending halt
condition in a manner similar to the assertion of the BKPTB signal. In all cases, the
occurrence of this type of breakpoint halts the processor in an imprecise manner.
Once the hardware breakpoint is asserted, the processor halts at the next sample
point. See Section 7.4.1 Theory of Operation for more detail.
3. The execution of the HALT, also known as BGND on the 683xx devices, instruction
immediately suspends execution and posts the halt status ($F) on the PST outputs.
By default, this is a supervisor instruction and attempted execution while in user mode
generates a privilege-violation exception. A User Halt Enable (UHE) control bit is
provided in the Configuration/Status Register (CSR) to allow execution of HALT in
user mode.
4. The assertion of the BKPTB input pin is treated as a pseudo-interrupt, i.e., the halt
condition is made pending until the processor core samples for halts/interrupts. The
processor samples for these conditions once during the execution of each instruction.
If there is a pending halt condition at the sample time, the processor suspends
execution and enters the halted state. The halt status, $F, is reflected in the PST
outputs.
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There are two special cases involving the assertion of the BKPTB pin to be considered.
After the master reset signal (MRSTB) is negated, the processor waits for 16 clock cycles
before beginning reset exception processing. If the BKPTB input pin is asserted within the
first eight cycles after MRSTB is negated, the processor will enter the halt state, signaling
that halt status, $F, on the PST outputs. While in this state, all resources accessible via the
debug module can be referenced. This is the only opportunity to force the ColdFire2/2M into
emulation mode via the EMU bit in the configuration/status register (CSR). Once the system
initialization is complete, the processor response to a BDM GO command is dependent on
the set of BDM commands performed while breakpointed. Specifically, if the processor’s PC
register was loaded, then the GO command simply causes the processor to exit the halted
state and pass control to the instruction address contained in the PC. Note in this case, the
normal reset exception processing is bypassed. Conversely, if the PC register was not
loaded, then the GO command causes the processor to exit the halted state and continue
with reset exception processing.
The ColdFire2/2M also handles a special case with the assertion of BKPTB while the
processor is stopped by execution of the STOP instruction. For this case, the processor exits
the stopped mode and enters the halted state. Once halted, the standard BDM commands
may be exercised. When the processor is restarted, it continues with the execution of the
next sequential instruction, i.e., the instruction following the STOP opcode.
The halt source is indicated in CSR[27:24]; for simultaneous halt conditions, the highest
priority source is indicated.
7.3.2 BDM Serial Interface
Once the CPU is halted and the halt status reflected on the PST outputs (PST[3:0] = $F),
the development system may send unrestricted commands to the debug module. The
debug module implements a synchronous protocol using a three-pin interface: development
serial clock (DSCLK), development serial input (DSI), and development serial output (DSO).
The development system serves as the serial communication channel master and is
responsible for generation of the clock (DSCLK). The operating range of the serial channel
is DC to 1/2 of the processor frequency. The channel uses a full duplex mode, where data
is transmitted and received simultaneously by both master and slave devices. The
transmission consists of 17-bit packets composed of a status/control bit and a 16-bit data
word. As seen in Figure 7-3, data is exchanged on the positive edge of CLK when DSCLK
is high (i.e. DSI is sampled and DSO is driven.) The DSCLK signal must also be sampled
low (on a positive edge of CLK) between each bit exchange. The MSB is transferred first.
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CLK
DSCLK
DSI
16
15
14
0
DSO
16
15
14
1
0
Figure 7-3. BDM Serial Transfer
Both DSCLK and DSI are synchronous inputs and must meet input setup and hold times
with respect to CLK. The DSCLK signal essentially acts as a pseudo “clock enable” and is
sampled on the rising edge of CLK. If the setup time of DSCLK is met, then the internal logic
transitions on the rising edge of CLK, and DSI is sampled on the same CLK rising edge. The
DSO output is specified as a delay from the DSCLK-enabled CLK rising edge. All events in
the debug module’s serial state machine are based on the rising edge of the microprocessor
clock (see Figure 7-4 below). Also refer to the Electrical Characteristics section of this
manual.
CLK
DSCLK
DSI
DSO
Figure 7-4. BDM Signal Sampling
7.3.2.1 RECEIVE PACKET FORMAT. The basic receive packet of information is 17 bits
long,16 data bits plus a status bit, as shown below in Figure 7-5.
16
15
0
S
DATA FIELD [15:0]
Figure 7-5. Receive BDM Packet
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Status[16]
The status bit indicates the status of CPU-generated messages (always single word), with
the data field encoded as listed in Table 7-2.
Table 7-2. CPU-Generated Message Encoding
S BIT
DATA
xxxx
MESSAGE TYPE
Valid data transfer
0
0
1
1
1
$FFFF
$0000
$0001
$FFFF
Command complete; status OK
Not ready with response; come again
TEA-terminated bus cycle; data invalid
Illegal command
Data Field[15:0]
The data field contains the message data to be communicated from the debug module to
the development system. The response message is always a single word, with the data field
encoded as shown in Table 7-2.
7.3.2.2 TRANSMIT PACKET FORMAT. The basic transmit packet of information is 17 bits
long,16 data bits plus a control bit, as shown below in Figure 7-6.
16
15
0
C
DATA FIELD [15:0]
Figure 7-6. Transmit BDM Packet
Control[16]
The control bit is not used but is reserved by Motorola for future use. Command and data
transfers initiated by the development system should clear bit 16.
Data Field[15:0]
The data field contains the message data to be communicated from the development
system to the debug module.
7.3.3 BDM Command Set
The ColdFire2/2M supports a subset of BDM instructions from the current 683xx parts, as
well as extensions to provide access to new hardware features. The BDM commands should
not be issued whenever the ColdFire2/2M is accessing the debug module registers using
the WDEBUG instruction.
7.3.3.1 BDM COMMAND SET SUMMARY. The BDM command set is summarized in
Figure 7-6. Subsequent paragraphs contain detailed descriptions of each command.
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Table 7-3. BDM Command Summary
CPU
IMPACT
COMMAND
MNEMONIC
DESCRIPTION
PAGE
1
READ A/D REGISTER RAREG/RDREG Read the selected address or data register and HALTED
return the results via the serial interface.
7-13
WRITE A/D REGISTER WAREG/WDREG The data operand is written to the specified
address or data register.
HALTED
7-13
7-14
7-16
7-17
READ MEMORY
LOCATION
READ
WRITE
DUMP
Read the data at the memory location specified CYCLE
by the longword address. STEAL
WRITE MEMORY
LOCATION
Write the operand data to the memory location CYCLE
specified by the longword address. STEAL
DUMP MEMORY
BLOCK
Used in conjunction with the READ command CYCLE
to dump large blocks of memory. An initial
READ is executed to set up the starting
address of the block and to retrieve the first
result. Subsequent operands are retrieved with
the DUMP command.
STEAL
FILL MEMORY BLOCK
FILL
GO
Used in conjunction with the WRITE command CYCLE
to fill large blocks of memory. An initial WRITE STEAL
is executed to set up the starting address of the
block and to supply the first operand.
7-19
7-21
Subsequent operands are written with the FILL
command.
RESUME EXECUTION
NO OPERATION
The pipeline is flushed and refilled before
resuming instruction execution at the current
PC.
HALTED
NOP
NOP performs no operation and may be used PARALLEL
as a null command.
7-21
7-22
7-23
7-24
7-25
READ CONTROL
REGISTER
RCREG
Read the system control register.
HALTED
WRITE CONTROL
REGISTER
WCREG
RDMREG
WDMREG
Write the operand data to the system control
register.
HALTED
READDEBUGMODULE
REGISTER
Read the Debug Module register.
PARALLEL
WRITE DEBUG
MODULE REGISTER
Write the operand data to the Debug Module PARALLEL
register.
NOTE: 1. General command effect and/or requirements on CPU operation:
Halted - The CPU must be halted to perform this command
Steal - Command generates bus cycles which can be interleaved with CPU accesses
Parallel - Command is executed in parallel with CPU activity
Refer to command summaries for detailed operation descriptions.
7.3.3.2 COLDFIRE BDM COMMANDS. All ColdFire Family BDM commands include a 16-
bit operation word followed by an optional set of one or more extension words.
15
10
9
8
7
6
5
4
3
2
0
OPERATION
0
R/W
OP SIZE
0
0
A/D
REGISTER
EXTENSION WORD(S)
BDM Command Format
Operation Field
The operation field specifies the command.
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R/W Field
The R/W field specifies the direction of operand transfer. When the bit is set, the transfer is
from the CPU to the development system. When the bit is cleared, data is written to the CPU
or to memory from the development system.
Operand Size
For sized operations, this field specifies the operand data size. All addresses are expressed
as 32-bit absolute values. The size field is encoded as listed in Table 7-4.
Table 7-4. BDM Size Field Encoding
ENCODING
OPERAND SIZE
Byte
00
01
10
11
Word
Long
Reserved
Address / Data (A/D) Field
The A/D field is used in commands that operate on address and data registers in the
processor. It determines whether the register field specifies a data or address register. A one
indicates an address register; zero, a data register.
Register Field
In commands that operate on processor registers, this field specifies which register is
selected. The field value contains the register number.
Extension Word(s) (as required):
Certain commands require extension words for addresses and/or immediate data.
Addresses require two extension words because only absolute long addressing is permitted.
Immediate data can be either one or two words in length—byte and word data each require
a single extension word; longword data requires two words. Both operands and addresses
are transferred most significant word first. In the following descriptions of the BDM command
set, the optional set of extension words is defined as the “Operand Data.”
7.3.3.3 COMMAND SEQUENCE DIAGRAM. A command sequence diagram (see Figure
7-7) illustrates the serial bus traffic for each command. Each bubble in the diagram
represents a single 17-bit transfer across the bus. The top half in each bubble corresponds
to the data transmitted by the development system to the debug module; the bottom half
corresponds to the data returned by the debug module in response to the development
system commands. Command and result transactions are overlapped to minimize latency.
The cycle in which the command is issued contains the development system command
mnemonic (in this example, “read memory location”). During the same cycle, the debug
module responds with either the lowest order results of the previous command or with a
command complete status (if no results were required).
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During the second cycle, the development system supplies the high-order 16 bits of the
memory address. The debug module returns a “not ready” response ($10000) unless the
received command was decoded as unimplemented, in which case the response data is the
illegal command ($1FFFF) encoding. If an illegal command response occurs, the
development system should retransmit the command.
NOTE
The response can be ignored unless a memory bus cycle is in
progress. Otherwise, the debug module can accept a new serial
transfer after eight system clock periods.
In the third cycle, the development system supplies the low-order 16 bits of a memory
address. The debug module always returns the “not ready” response in this cycle. At the
completion of the third cycle, the debug module initiates a memory read operation. Any
serial transfers that begin while the memory access is in progress return the “not ready”
response.
Results are returned in the two serial transfer cycles following the completion of the memory
access. The data transmitted to the debug module during the final transfer is the opcode for
the following command. Should a memory access generate a bus error, an error status
($10001) is returned in place of the result data.
COMMANDS TRANSMITTED TO THE DEBUG MODULE
COMMAND CODE TRANSMITTED DURING THIS CYCLE
HIGH-ORDER 16 BITS OF MEMORY ADDRESS
LOW-ORDER 16 BITS OF MEMORY ADDRESS
NONSERIAL-RELATED ACTIVITY
SEQUENCE TAKEN IF
OPERATION HAS NOT
COMPLETED
NEXT
COMMAND
CODE
READ
MEMORY
LOCATION
READ (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
XXX
"NOT READY"
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
"ILLEGAL"
NEXT CMD
"NOT READY"
XXX
NEXT CMD
"NOT READY"
BERR
DATA UNUSED FROM
THIS TRANSFER
SEQUENCE TAKEN IF BUS
ERROR OCCURS ON
MEMORY ACCESS
SEQUENCE TAKEN IF
ILLEGAL COMMAND
IS RECEIVED BY DEBUG MODULE
RESULTS FROM PREVIOUS COMMAND
RESPONSES FROM THE DEBUG MODULE
HIGH- AND LOW-ORDER
16 BITS OF RESULT
Figure 7-7. Command Sequence Diagram
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7.3.3.4 COMMAND SET DESCRIPTIONS. The BDM command set is summarized in
Table 7-3. Subsequent paragraphs contain detailed descriptions of each command.
Note
All the accompanying BDM commands assume the control bit
(C) is zero. The BDM results are defined with the status bit (S)
as zero. Refer to Section 7.3.2 BDM Serial Interface for
information on the serial packet format
Unassigned command opcodes are reserved by Motorola for future expansion. All unused
command formats within any revision level will perform a NOP and return the ILLEGAL
command response.
7.3.3.4.1 Read A/D Register (RAREG/RDREG). Read the selected address or data
register and return the 32-bit result. A bus error response is returned if the CPU core is not
halted.
Formats:
\
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$1
$8
A/D
REGISTER
RAREG/RDREG Command
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA [31:16]
DATA [15:0]
RAREG/RDREG Result
Command Sequence:
RAREG/RDREG
???
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
NEXT CMD
"NOT READY"
BERR
Operand Data:
None
Result Data:
The contents of the selected register are returned as a longword value. The data is returned
most significant word first.
7.3.3.4.2 Write A/D Register (WAREG/WDREG). The operand data is written to the
specified address or data register. All 32 register bits are altered by the write. A bus error
response is returned if the CPU core is not halted.
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Command Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$0
$8
A/D
REGISTER
DATA [31:16]
DATA [15:0]
WAREG/WDREG Command
Command Sequence:
WDREG/WAREG
???
MS DATA
"NOT READY"
LS DATA
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
NEXT CMD
BERR
"NOT READY"
Operand Data:
Longword data is written into the specified address or data register. The data is supplied
most significant word first.
Result Data:
Command complete status will be indicated by returning the data $FFFF (with the status bit
cleared) when the register write is complete.
7.3.3.4.3 Read Memory Location (READ). Read the operand data from the memory
location specified by the longword address. The address space is defined by the contents
of the low-order 5 bits {TT, TM} of the address attribute register (AATR). The hardware
forces the low-order bits of the address to zeros for word and longword accesses to ensure
that operands are always accessed on natural boundaries: words on 0-modulo-2 addresses,
longwords on 0-modulo-4 addresses.
Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$1
$9
$0
$0
ADDRESS [31:16]
ADDRESS [15:0]
Byte READ Command
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
X
DATA [7:0]
Byte READ Result
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Debug Support
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$1
$9
$4
$0
ADDRESS [31:16]
ADDRESS [15:0]
Word READ Command
15
15
14
14
13
13
12
12
11
11
10
10
9
8
7
6
5
5
4
4
3
3
2
2
1
1
0
0
DATA [15:0]
Word READ Result
9
8
7
6
$1
$9
$8
$0
ADDRESS [31:16]
ADDRESS [15:0]
Long READ Command
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA [31:16]
DATA [15:0]
Long READ Result
Command Sequence:
READ
READ (B/W)
???
MS ADDR
"NOT READY"
LS ADDR
XXX
"NOT READY"
MEMORY
"NOT READY"
LOCATION
NEXT CMD
RESULT
XXX
NEXT CMD
"NOT READY"
BERR
READ
READ (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
XXX
"NOT READY"
MEMORY
"NOT READY"
LOCATION
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
NEXT CMD
"NOT READY"
BERR
Operand Data:
The single operand is the longword address of the requested memory location.
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Result Data:
The requested data is returned as either a word or longword. Byte data is returned in the
least significant byte of a word result, with the upper byte undefined. Word results return 16
bits of significant data; longword results return 32 bits. A value of $0001 (with the status bit
set) will be returned if a bus error occurs.
7.3.3.4.4 Write Memory Location (WRITE). Write the operand data to the memory
location specified by the longword address. The address space is defined by the contents
of the low-order 5 bits {TT, TM} of the address attribute register (AATR). The hardware
forces the low-order bits of the address to zeros for word and longword accesses to ensure
that operands are always accessed on natural boundaries: words on 0-modulo-2 addresses,
longwords on 0-modulo-4 addresses.
Formats:
15
14
13
12
11
10
9
8
7
6
5
5
5
4
3
2
2
2
1
1
1
0
0
0
$1
$1
$1
$8
$0
$0
$0
$0
ADDRESS [31:16]
ADDRESS [15:0]
X
X
X
X
X
X
X
X
DATA [7:0]
Byte WRITE Command
15
14
13
12
11
10
9
8
7
6
4
3
$8
$4
ADDRESS [31:16]
ADDRESS [15:0]
DATA [15:0]
Word WRITE Command
15
14
13
12
11
10
9
8
7
6
4
3
$8
$8
ADDRESS [31:16]
ADDRESS [15:0]
DATA [31:16]
DATA [15:0]
Long WRITE Command
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Debug Support
Command Sequence:
WRITE
MEMORY
LOCATION
WRITE (B/W)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
DATA
"NOT READY"
XXX
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
WRITE (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
MS DATA
"NOT READY"
WRITE
MEMORY
LOCATION
LS DATA
"NOT READY"
XXX
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
Operand Data:
Two operands are required for this instruction. The first operand is a longword absolute
address that specifies a location to which the operand data is to be written. The second
operand is the data. Byte data is transmitted as a 16-bit word, justified in the least significant
byte; 16- and 32-bit operands are transmitted as 16 and 32 bits, respectively.
Result Data:
Successful write operations will be indicated by returning the data $FFFF (with the status bit
cleared) when the register write is complete. A value of $0001 (with the status bit set) will be
returned if a bus error occurs.
7.3.3.4.5 Dump Memory Block (DUMP). DUMP is used in conjunction with the READ
command to dump large blocks of memory. An initial READ is executed to set up the starting
address of the block and to retrieve the first result. The DUMP command retrieves
subsequent operands. The initial address is incremented by the operand size (1, 2, or 4) and
saved in a temporary register (address breakpoint high (ABHR)). Subsequent DUMP
commands use this address, perform the memory read, increment it by the current operand
size, and store the updated address in ABHR.
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NOTE
The DUMP command does not check for a valid address in
ABHR—DUMP is a valid command only when preceded by
another DUMP, NOP or by a READ command. Otherwise, an
illegal command response is returned. The NOP command can
be used for intercommand padding without corrupting the
address pointer.
The size field is examined each time a DUMP command is given, allowing the operand size
to be dynamically altered.
Command Formats:
15
14
13
12
11
10
9
8
7
6
5
5
5
5
5
5
4
3
2
2
2
2
2
2
1
1
1
1
1
1
0
0
0
0
0
0
$1
$1
$1
$D
$0
$0
$0
$0
Byte DUMP Command
15
14
13
12
11
10
9
8
7
6
4
3
X
X
X
X
X
X
X
X
DATA [7:0]
Byte DUMP Result
15
15
15
15
14
14
14
14
13
13
13
13
12
12
12
12
11
11
11
11
10
10
10
10
9
8
7
6
4
4
4
4
3
3
3
3
$D
$4
Word DUMP Command
9
8
7
6
DATA [15:0]
Word DUMP Result
9
8
7
6
$D
$8
Long DUMP Command
9
8
7
6
DATA [31:16]
DATA [15:0]
Long DUMP Result
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Command Sequence:
READ
MEMORY
LOCATION
DUMP (B/W)
???
XXX
"NOT READY"
NEXT CMD
RESULT
XXX
"ILLEGAL"
XXX
BERR
NEXT CMD
"NOT READY"
NEXT CMD
"NOT READY"
READ
MEMORY
LOCATION
DUMP (LONG)
???
XXX
"NOT READY"
NEXT CMD
LS RESULT
NEXT CMD
MS RESULT
XXX
"ILLEGAL"
XXX
BERR
NEXT CMD
"NOT READY"
NEXT CMD
"NOT READY"
Operand Data:
None
Result Data:
Requested data is returned as either a word or longword. Byte data is returned in the least
significant byte of a word result. Word results return 16 bits of significant data; longword
results return 32 bits. A value of $0001 (with the status bit set) will be returned if a bus error
occurs.
7.3.3.4.6 Fill Memory Block (FILL). FILL is used in conjunction with the WRITE command
to fill large blocks of memory. An initial WRITE is executed to set up the starting address of
the block and to supply the first operand. The FILL command writes subsequent operands.
The initial address is incremented by the operand size (1, 2, or 4) and is saved in address
breakpoint high (ABHR) after the memory write. Subsequent FILL commands use this
address, perform the write, increment it by the current operand size, and store the updated
address in ABHR.
NOTE
The FILL command does not check for a valid address in
ABHR—FILL is a valid command only when preceded by
another FILL, NOP or by a WRITE command. Otherwise, an
illegal command response is returned. The NOP command can
be used for intercommand padding without corrupting the
address pointer.
The size field is examined each time a FILL command is processed, allowing the operand
size to be altered dynamically.
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Debug Support
Formats:
15
14
13
12
11
10
9
8
7
6
5
5
5
4
3
2
2
2
1
1
1
0
0
0
$1
$1
$1
$C
$0
$0
$0
$0
X
X
X
X
X
X
X
X
DATA [7:0]
Byte FILL Command
15
15
14
14
13
13
12
12
11
11
10
10
9
8
7
6
4
4
3
3
$C
$4
DATA [15:0]
Word FILL Command
9
8
7
6
$C
$8
DATA [31:16]
DATA [15:0]
Long FILL Command
Command Sequence:
WRITE
LS DATA
MEMORY
XXX
"NOT READY"
FILL (B/W)
???
MS DATA
"NOT READY"
"NOT READY"
LOCATION
XXX
NEXT CMD
NEXT CMD
"CMD COMPLETE"
"ILLEGAL"
"NOT READY"
NEXT CMD
"NOT READY"
XXX
BERR
WRITE
FILL (LONG)
???
DATA
"NOT READY"
XXX
MEMORY
"NOT READY"
LOCATION
NEXT CMD
NEXT CMD
"NOT READY"
XXX
"ILLEGAL"
"CMD COMPLETE"
NEXT CMD
XXX
"NOT READY"
BERR
Operand Data:
A single operand is data to be written to the memory location. Byte data is transmitted as a
16-bit word, justified in the least significant byte; 16- and 32-bit operands are transmitted as
16 and 32 bits, respectively.
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Result Data:
Command complete status will be indicated by returning the data $FFFF (with the status bit
cleared) when the register write is complete. A value of $0001 (with the status bit set) will be
returned if a bus error occurs.
7.3.3.4.7 Resume Execution (GO). The pipeline is flushed and refilled before resuming
normal instruction execution. Prefetching begins at the current PC and current privilege
level. If either the PC or SR is altered during BDM, the updated value of these registers is
used when prefetching begins.
Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$0
$C
$0
$0
GO Command
Command Sequence:
GO
???
NEXT CMD
"CMD COMPLETE"
Operand Data:
None
Result Data:
The “command complete” response ($0FFFF) is returned during the next shift operation.
7.3.3.4.8 No Operation (NOP). NOP performs no operation and may be used as a null
command where required.
Formats:
15
12
11
8
7
4
3
0
$0
$0
$0
$0
NOP Command
Command Sequence:
NOP
???
NEXT CMD
"CMD COMPLETE"
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Debug Support
Operand Data:
None
Result Data:
The “command complete” response, $FFFF (with the status bit cleared), is returned during
the next shift operation.
7.3.3.4.9 Read Control Register (RCREG). Read the selected control register and return
the 32-bit result. Accesses to the processor/memory control registers are always 32 bits in
size, regardless of the implemented register width. The second and third words of the
command effectively form a 32-bit address used by the debug module to generate a special
bus cycle to access the specified control register. The 12-bit Rc field is the same as that
used by the MOVEC instruction.
Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$0
$0
$9
$0
$8
$0
Rc
$0
$0
RCREG Command
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA [31:16]
DATA [15:0]
RCREG Result
Rc encoding:
Table 7-5. Control Register Map
Rc
REGISTER DEFINITION
Cache Control Register (CACR)
Access Control Register 0 (ACR0)
Access Control Register 1 (ACR1)
Vector BASE Register (VBR)
MAC Status Register (MACSR)†
MAC Mask Register (MASK)†
MAC Accumulator (ACC)†
$002
$004
$005
$801
$804
$805
$806
$80E
$80F
$C00
$C04
Status Register (SR)
Program Counter (PC)
ROM Base Address Register (ROMBAR0)
RAM Base Address Register (RAMBAR0)
NOTE: †Available on the ColdFire2M only.
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Debug Support
Command Sequence:
READ
MEMORY
LOCATION
RCREG
???
EXT WORD
"NOT READY"
EXT WORD
"NOT READY"
XXX
"NOT READY"
NEXT CMD
LS RESULT
XXX
MS RESULT
XXX
NEXT CMD
"NOT READY"
BERR
Operand Data:
The single operand is the 32-bit Rc control register select field.
Result Data:
The contents of the selected control register are returned as a longword value. The data is
returned most-significant-word first. For those control registers with widths less than 32 bits,
only the implemented portion of the register is guaranteed to be correct. The remaining bits
of the longowrd are undefined. As an example, a read of the 16-bit SR will return the SR in
the lower word and undefined data in the upper word.
7.3.3.4.10 Write Control Register (WCREG). The operand (longword) data is written to
the specified control register. The write alters all 32 register bits.
Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$0
$0
$8
$0
$8
$0
Rc
$0
$0
DATA [31:16]
DATA [15:0]
WCREG Command
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Debug Support
Command Sequence:
WCREG
???
EXT WORD
"NOT READY"
EXT WORD
"NOT READY"
MS DATA
"NOT READY"
WRITE
MEMORY
LOCATION
LS DATA
"NOT READY"
XXX
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
Operand Data:
Two operands are required for this instruction. The first long operand selects the register to
which the operand data is to be written. The second operand is the data.
Result Data:
Successful write operations return $FFFF. Bus errors on the write cycle are indicated by the
assertion of bit 16 in the status message and by a data pattern of $0001.
7.3.3.4.11 Read Debug Module Register (RDMREG). Read the selected debug module
register and return the 32-bit result. The only valid register selection for the RDMREG
command is the CSR (DRc = $0).
Command Formats:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$D
$8
DRc
RDMREG BDM Command
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA [31:16]
DATA [15:0]
RDMREG BDM Result
DRc encoding:
Table 7-6. Definition of DRc Encoding - Read
DRc[3:0]
DEBUG REGISTER DEFINITION
Configuration/Status
Reserved
MNEMONIC
INITIAL STATE
$0
CSR
-
$0
–
$1-$F
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Debug Support
Command Sequence:
RDMREG
???
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
NEXT CMD
"ILLEGAL"
"NOT READY"
Operand Data:
None
Result Data:
The contents of the selected debug register are returned as a longword value. The data is
returned most-significant-word first.
7.3.3.4.12 Write Debug Module Register (WDMREG). The operand (longword) data is
written to the specified debug module register. All 32 bits of the register are altered by the
write. The DSCLK signal must be inactive while CPU accesses are being performed.
Command Format:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
$2
$C
$8
DRc
DATA [31:16]
DATA [15:0]
WDMREG BDM Command
DRc encoding:
Table 7-7. Definition of DRc Encoding - Write
DRc[3:0]
DEBUG REGISTER DEFINITION
Configuration/Status
Reserved
MNEMONIC INITIAL STATE
$0
$1-$5
$6
CSR
-
$0
–
Bus Attributes and Mask
Trigger Definition
AATR
TDR
PBR
PBMR
–
$0005
$7
$0
–
$8
PC Breakpoint
$9
PC Breakpoint Mask
Reserved
–
$A-$B
$C
–
Operand Address High Breakpoint
Operand Address Low Breakpoint
Data Breakpoint
ABHR
ABLR
DBR
DBMR
–
$D
–
$E
–
$F
Data Breakpoint Mask
–
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Debug Support
Command Sequence:
WDMREG
???
MS DATA
"NOT READY"
LS DATA
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
NEXT CMD
"ILLEGAL"
"NOT READY"
Operand Data:
Longword data is written into the specified debug register. The data is supplied most-
significant-word first.
Result Data:
Command complete status ($0FFFF) is returned when register write is complete.
7.3.3.4.13 Unassigned Opcodes. Unassigned command opcodes are reserved by
Motorola. All unused command formats within any revision level will perform a NOP and
return the ILLEGAL command response.
7.4 REAL-TIME DEBUG SUPPORT
The ColdFire2/2M provides support for the debug of real-time applications. For these types
of embedded systems, the processor cannot be halted during debug, but must continue to
operate. The foundation of this area of debug support is that while the processor cannot be
halted to allow debug, the system can tolerate small intrusions into the real-time operation.
As discussed in the previous section, the debug module provides a number of hardware
resources to support various hardware breakpoint functions. Specifically, three types of
breakpoints are supported: PC with mask, operand address range, and data with mask.
These three basic breakpoints can be configured into one- or two-level triggers with the
exact trigger response also programmable. The debug module programming model is
accessible from either the external development system using the serial interface or from
the processor’s supervisor programming model using the WDEBUG instruction.
7.4.1 Theory of Operation
The breakpoint hardware can be configured to respond to triggers in several ways. The
desired response is programmed into the Trigger Definition Register. In all situations where
a breakpoint triggers, an indication is provided on the DDATA output port, when not
displaying captured operands or branch addresses, as shown in Table 7-8.
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Table 7-8. DDATA, CSR[31:28] Breakpoint Response
DDATA[3:0], CSR[31:28]
BREAKPOINT STATUS
No breakpoints enabled
Waiting for level 1 breakpoint
Level 1 breakpoint triggered
Reserved
$0
$1
$2
$3-4
$5
Waiting for level 2 breakpoint
Level 2 breakpoint triggered
Reserved
$6
$7-$F
The breakpoint status is also posted in the CSR.
The new BDM instructions load and configure the desired breakpoints using the appropriate
registers. As the system operates, a breakpoint trigger generates a response as defined in
the TDR. If the system can tolerate the processor being halted, a BDM entry can be used.
With the TRC bits of the TDR = $1, the breakpoint trigger causes the core to halt as reflected
in the status of PST = $F. For PC breakpoints, the halt occurs before the targeted instruction
is executed. For address and data breakpoints, the processor may have executed several
additional instructions. As a result, trigger reporting is considered imprecise.
If the processor core cannot be halted, the special debug interrupt can be used. With this
configuration, TRC bits of the TDR = $2, the breakpoint trigger is converted into a debug
interrupt to the processor (see Section 4.2.8 Debug Interrupt.) This interrupt is treated as
higher than the nonmaskable level 7 interrupt request. As with all interrupts, it is made
pending when the processor samples, once per instruction. Again, the hardware forces the
PC breakpoint to occur immediately (before the execution of the targeted instruction). This
is possible because the PC breakpoint comparison is enabled at the same time the interrupt
sampling occurs. For the address and data breakpoints, the reporting is considered
imprecise because several additional instructions may be executed after the triggering
address or data is seen.
Once the debug interrupt is recognized, the processor aborts execution and initiates
exception processing. At the initiation of the exception processing, the core enters emulator
mode. After the standard 8-byte exception stack is created, the processor fetches a unique
exception vector, $C, from the vector table.
Execution continues at the instruction address contained in this exception vector. All
interrupts are ignored while in emulator mode. Users can program the debug-interrupt
handler to perform the necessary context saves using the supervisor instruction set. As an
example, this handler may save the state of all the program-visible registers as well as the
current context into a reserved memory area.
Once the required operations are complete, the return-from-exception (RTE) instruction is
executed and the processor exits emulator mode. Once the debug interrupt handler has
completed its execution, the external development system can then access the reserved
memory locations using the BDM commands to read memory.
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Debug Support
7.4.1.1 EMULATOR MODE. Emulator mode is used to facilitate non-intrusive emulator
functionality. This mode can be entered in three different ways:
• The EMU bit in the configuration/status register (CSR) may be programmed to force the
ColdFire2/2M into emulation mode. This bit is examined only when MRSTB is negated
and the processor begins reset exception processing. It may be set while the ColdFire2/
2M is halted before the reset exception processing begins. Refer to Section 7.3.1 CPU
Halt.
• A debug interrupt always enters emulation mode when the debug interrupt exception
processing begins.
• The TCR bit in the CSR may be programmed to force the ColdFire2/2M into emulation
mode when trace exception processing begins.
During emulation mode, the ColdFire2/2M’s exhibits the following properties:
• All interrupts are ignored, including level seven.
• If the MAP bit in the CSR is set, all memory accesses are forced, including the
exception stack frame writes and the vector fetch, into a specially mapped address
space signalled by TT = $2, TM = $5 or $6.
• If the MAP bit in the CSR is set, all caching of memory accesses is disabled.
The return-from-exception (RTE) instruction exits emulation mode. The processor status
output port provides a unique encoding for emulator mode entry ($D) and exit ($7).
7.4.1.2 REUSE OF DEBUG MODULE HARDWARE. The debug module implementation
provides a common hardware structure for both BDM and breakpoint functionality. Several
structures are used for both BDM and breakpoint purposes. Table 7-9 identifies the shared
hardware structures.
Table 7-9. Shared BDM/Breakpoint Hardware
REGISTER
BDM FUNCTION
BREAKPOINT FUNCTION
Bus attributes for all memory
commands
Attributes for address
breakpoint
AATR
Address for all memory commands
Address for address
breakpoint
ABHR
DBR
Data for All BDM write commands
Data for data breakpoint
The shared use of these hardware structures means the loading of the register to perform
any specified function is destructive to the shared function. For example, if an operand
address breakpoint is loaded into the debug module, a BDM command to access memory
overwrites the breakpoint. If a data breakpoint is configured, a BDM write command
overwrites the breakpoint contents.
7.4.2 Programming Model
In addition to the existing BDM commands that provide access to the processor’s registers
and the memory subsystem, the debug module contains nine registers to support the
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Debug Support
required functionality. All of these registers are treated as 32-bit quantities, regardless of the
actual number of bits in the implementation. The registers, known as the debug control
registers, are accessed through the BDM port using two new BDM commands: WDMREG
and RDMREG. These commands contain a 4-bit field, DRc, which specifies the particular
register being accessed.
These registers are also accessible from the processor’s supervisor programming model
through the execution of the WDEBUG instruction. Thus, the breakpoint hardware within the
debug module may be accessed by the external development system using the serial
interface, or by the operating system running on the processor core. It is the responsibility
of the software to guarantee that all accesses to these resources are serialized and logically
consistent. The hardware provides a locking mechanism in the CSR to allow the external
development system to disable any attempted writes by the processor to the breakpoint
registers (setting IPW = 1). The BDM commands should not be issued whenever the
ColdFire2/2M is accessing the debug module registers using the WDEBUG instruction.
Figure 7-8 illustrates the debug module programming model.
31
15
15
0
0
ADDRESS
BREAKPOINTREGISTERS
ABLR
ABHR
7
ADDRESSATTRIBUTE
REGISTER
AATR
PCBREAKPOINT
REGISTERS
PBR
PBMR
DATABREAKPOINT
REGISTERS
DBR
DBMR
TRIGGERDEFINITION
REGISTER
CONFIGURATION/
STATUS
TDR
CSR
Figure 7-8. Debug Programming Model
7.4.2.1 ADDRESS BREAKPOINT REGISTERS (ABLR, ABHR). The address breakpoint
registers define a region in the operand address space of the processor that can be used as
part of the trigger. The full 32-bits of the ABLR and ABHR values are compared with the
internal address signals of the ColdFire2/2M. The trigger definition register (TDR)
determines if the trigger is the inclusive range bound by ABLR and ABHR, all addresses
outside this range, or the address in ABLR only. The ABHR is accessible in supervisor mode
as debug control register $C using the WDEBUG instruction and via the BDM port using the
RDMREG and WDMREG commands. The ABLR is accessible in supervisor mode as debug
control register $D using the WDEBUG instruction and via the BDM port using the
WDMREG commands. The ABHR is overwritten by the BDM hardware when accessing
memory as described in Section 7.4.1.2 Reuse of Debug Module Hardware.
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Debug Support
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Address Breakpoint Low Register (ABLR)
Field Definition:
ADDRESS[31:0]–Low Address
This field contains the 32-bit address which marks the lower bound of the address
breakpoint range.
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Address Breakpoint High Register (ABHR)
Field Definition:
ADDRESS[31:0]–High Address
This field contains the 32-bit address which marks the upper bound of the address
breakpoint range.
7.4.2.2 ADDRESS ATTRIBUTE REGISTER (AATR). The AATR defines the address
attributes and a mask to be matched in the trigger. The AATR value is compared with the
internal address attribute signals of the ColdFire2/2M, as defined by the setting of the TDR.
The AATR is accessible in supervisor mode as debug control register $6 using the
WDEBUG instruction and via the BDM port using the WDMREG command. The lower five
bits of the AATR are also used for BDM command definition to define the address space for
memory references as described in Section 7.4.1.2 Reuse of Debug Module Hardware.
BITS
FIELD
RESET
R/W
15
RM
0
14
13
12
11
10
8
7
R
0
6
5
4
3
2
0
SZM
TTM
TMM
0
SZ
0
TT
0
TM
101
W
0
0
W
W
W
W
W
W
W
Address Attribute Register (AATR)
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Debug Support
Field Definitions:
RM[15]–Read/Write Mask
This field corresponds to the R-field. Setting this bit causes R to be ignored in address
comparisons.
SZM[14:13]–Size Mask
This field corresponds to the SZ field. Setting a bit in this field causes the corresponding bit
in SZ to be ignored in address comparisons.
TTM[12:11]–Transfer Type Mask
This field corresponds to the TT field. Setting a bit in this field causes the corresponding bit
in TT to be ignored in address comparisons.
TMM[10:8]–Transfer Modifier Mask
This field corresponds to the TM field. Setting a bit in this field causes the corresponding bit
in TM to be ignored in address comparisons.
R[7]–Read/Write
This field is compared with the internal R/W signal of the ColdFire2/2M. A high level
indicates a read cycle and a low level indicates a write cycle.
SZ[6:5]—Size
This field is compared to the internal size signals of the ColdFire2/2M. These signals
indicate the data size for the bus transfer.
00 = Longword
01 = Byte
10 = Word
11 = Reserved
TT[4:3]—Transfer Type
This field is compared with the internal TT signals of the ColdFire2/2M. These signals
indicate the transfer type for the bus transfer. These signals are always encoded as if the
ColdFire2/2M is in the ColdFire IACK mode (see Section 3.1.15 Master Transfer Type
(MTT[1:0]).)
00 = ColdFire2/2M Access
01 = Reserved
10 = Emulator Mode Access
11 = Acknowledge/CPU Space Access
These bits also define the TT encoding for BDM memory commands. In this case, the 01
encoding generates an alternate master access.
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TM[2:0]—Transfer Modifier
This field is compared with the internal TM signals of the ColdFire2/2M. These signals
provide supplemental information for each transfer type. These signals are always encoded
as if the ColdFire2/2M is in the ColdFire IACK mode (see Section 3.1.13 Master Transfer
Modifier (MTM[2:0]).) The encoding for normal ColdFire2/2M transfers is:
000 = Reserved
001 = User Data Access
010 = User Code Access
011 = Reserved
100 = Reserved
101 = Supervisor Data Access
110 = Supervisor Code Access
111 = Reserved
The encoding for emulator mode transfers is:
0xx = Reserved
100 = Reserved
101 = Emulator Mode Data Access
110 = Emulator Mode Code Access
111 = Reserved
The encoding for acknowledge/CPU space transfers is:
000 = CPU Space Access
001 = Interrupt Acknowledge Level 1
010 = Interrupt Acknowledge Level 2
011 = Interrupt Acknowledge Level 3
100 = Interrupt Acknowledge Level 4
101 = Interrupt Acknowledge Level 5
110 = Interrupt Acknowledge Level 6
111 = Interrupt Acknowledge Level 7
These bits also define the TM encoding for BDM memory commands.
7.4.2.3 PROGRAM COUNTER BREAKPOINT REGISTER (PBR, PBMR). The PC
breakpoint registers define a region in the code address space of the processor that can be
used as part of the trigger. The PBR value is masked by the PBMR value, allowing only
those bits in PBR that have a corresponding zero in PBMR to be compared with the
processor’s program counter register, as defined in the TDR. The PBR is accessible in
supervisor mode as debug control register $8 using the WDEBUG instruction and via the
BDM port using the RDMREG and WDMREG commands. The PBMR is accessible in
supervisor mode as debug control register $9 using the WDEBUG instruction and via the
BDM port using the WDMREG command.
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0
BITS
FIELD
RESET
R/W
31
ADDRESS
-
W
Program Counter Breakpoint Register (PBR)
Field Definition:
ADDRESS[31:0]–PC Breakpoint Address
This field contains the 32-bit address to be compared with the PC as a breakpoint trigger.
BITS
FIELD
RESET
R/W
31
0
MASK
-
W
Program Counter Breakpoint Mask Register (PBMR)
Field Definition:
MASK[31:0]–PC Breakpoint Mask
This field contains the 32-bit mask for the PC breakpoint trigger. A zero in a bit position
causes the corresponding bit in the PBR to be compared to the appropriate bit of the PC. A
one causes that bit to be ignored.
7.4.2.4 DATA BREAKPOINT REGISTER (DBR, DBMR). The data breakpoint registers
define a specific data pattern that can be used as part of the trigger into debug mode.The
DBR value is masked by the DBMR value, allowing only those bits in DBR that have a
corresponding zero in DBMR to be compared with internal data bus of the ColdFire2/2M, as
defined in the TDR. The DBR is accessible in supervisor mode as debug control register $E
using the WDEBUG instruction and via the BDM port using the RDMREG and WDMREG
commands. The DBMR is accessible in supervisor mode as debug control register $F using
the WDEBUG instruction and via the BDM port using the WDMREG command. The DBR is
overwritten by the BDM hardware when accessing memory as described in Section 7.4.1.2
Reuse of Debug Module Hardware.
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Data Breakpoint Register (DBR)
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Debug Support
Field Definition:
ADDRESS[31:0]–Data Breakpoint Value
This field contains the 32-bit value to be compared with the internal data bus as a breakpoint
trigger.
BITS
FIELD
RESET
R/W
31
0
MASK
-
W
Data Breakpoint Mask Register (DBMR)
Field Definition:
MASK[31:0]–Data Breakpoint Mask
This field contains the 32-bit mask for the data breakpoint trigger. A zero in a bit position
causes the corresponding bit in the DBR to be compared to the appropriate bit of the internal
data bus. A one causes that bit to be ignored.
The data breakpoint register supports both aligned and misaligned operand references. The
relationship between the processor address, the access size, and the corresponding
location within the 32-bit data bus is shown in Table 7-10.
Table 7-10. Misaligned Data Operand References
ADDRESS[1:0] ACCESS SIZE OPERAND LOCATION
00
01
10
11
00
10
00
Byte
Byte
Byte
Byte
Word
Word
Long
Data[31:24]
Data[23:16]
Data[15:8]
Data[7:0]
Data[31:16]
Data[15:0]
Data[31:0]
7.4.2.5 TRIGGER DEFINITION REGISTER (TDR). The TDR configures the operation of
the hardware breakpoint logic within the debug module and controls the actions taken under
the defined conditions. The breakpoint logic may be configured as a one- or two-level
trigger, where bits [31:16] of the TDR define the 2nd level trigger and bits [15:0] define the
first level trigger. The TDR is accessible in supervisor mode as debug control register $7
using the WDEBUG instruction and via the BDM port using the WDMREG command.
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MOTOROLA
Debug Support
BITS
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
EDL EDW EDW EDL EDL EDU EDU
FIELD
TRC
EBL
DI
EAI EAR EAL EPC PCI
W
0
L
0
U
0
L
0
M
0
M
0
U
0
RESE
T
0
0
0
0
0
0
0
0
R/W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
BITS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EDL EDW EDW EDL EDL EDU EDU
FIELD
-
EBL
DI
EAI EAR EAL EPC PCI
W
L
U
L
M
M
U
RESE
T
-
-
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R/W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
Trigger Definition Register (TDR)
Field Definitions:
TRC–Trigger Response Control
The trigger response control determines how the processor is to respond to a completed
trigger condition. The trigger response is always displayed on the DDATA pins.
00 = display on DDATA only
01 = processor halt
10 = debug interrupt
11 = reserved
EBL–Enable Breakpoint Level
If set, this bit serves as the global enable for the breakpoint trigger. If cleared, all breakpoints
are disabled.
EDLW–Enable Data Breakpoint for the Data Longword
If set, this bit enables the data breakpoint based on the entire internal data bus. The
assertion of any of the ED bits enables the data breakpoint. If all bits are cleared, the data
breakpoint is disabled.
EDWL–Enable Data Breakpoint for the Lower Data Word
If set, this bit enables the data breakpoint based on the low-order word of the internal data
bus.
EDWU–Enable Data Breakpoint for the Upper Data Word
If set, this bit enables the data breakpoint trigger based on the high-order word of the internal
data bus.
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ColdFire2/2M User’s Manual
7-35
Debug Support
EDLL–Enable Data Breakpoint for the Lower Lower Data Byte
If set, this bit enables the data breakpoint trigger based on the low-order byte of the low-
order word of the internal data bus.
EDLM–Enable Data Breakpoint for the Lower Middle Data Byte
If set, this bit enables the data breakpoint trigger based on the high-order byte of the low-
order word of the internal data bus.
EDUM–Enable Data Breakpoint for the Upper Middle Data Byte
If set, this bit enables the data breakpoint trigger on the low-order byte of the high-order word
of the internal data bus.
EDUU–Enable Data Breakpoint for the Upper Upper Data Byte
If set, this bit enables the data breakpoint trigger on the high-order byte of the high-order
word of the internal data bus.
DI–Data Breakpoint Invert
This bit provides a mechanism to invert the logical sense of all the data breakpoint
comparators. This can develop a trigger based on the occurrence of a data value not equal
to the one programmed into the DBR.
EAI–Enable Address Breakpoint Inverted
If set, this bit enables the address breakpoint based outside the range defined by ABLR and
ABHR. The assertion of any of the EA bits enables the address breakpoint. If all three bits
are cleared, this breakpoint is disabled.
EAR–Enable Address Breakpoint Range
If set, this bit enables the address breakpoint based on the inclusive range defined by ABLR
and ABHR.
EAL–Enable Address Breakpoint Low
If set, this bit enables the address breakpoint based on the address contained in the ABLR.
EPC–Enable PC Breakpoint
If set, this bit enables the PC breakpoint.
PCI–PC Breakpoint Invert
If set, this bit allows execution outside a given region as defined by PBR and PBMR to
enable a trigger. If cleared, the PC breakpoint is defined within the region defined by PBR
and PBMR.
7.4.2.6 CONFIGURATION/STATUS REGISTER (CSR). The CSR defines the operating
configuration for the processor and memory subsystem. In addition to defining the
microprocessor configuration, this register also contains status information from the
breakpoint logic. The CSR is cleared during system reset. The CSR can be read and written
to by the external development system and written to by the supervisor programming model.
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MOTOROLA
Debug Support
The CSR is accessible in supervisor mode as debug control register $0 using the WDEBUG
instruction and via the BDM port using the RDMREG and WDMREG commands.
BITS
31
28
27
26
25
24
23
17
16
HAL BKP
FIELD
STATUS
FOF TRG
-
IPW
T
0
T
0
RESE
T
0
0
0
-
-
0
1
R/W
R
R
R
R
R
R/W
BITS
15
14
13
12
11
10
9
8
7
6
5
4
3
0
FIELD MAP TRC EMU
DDC
UHE
BTB
0
-
NPL
IPI SSM
-
-
-
RESE
T
0
0
0
0
0
0
0
0
0
R/W† R/W R/W R/W
R/W
R/W
R/W
R
R/W R/W R/W
NOTE: †The CSR is a write only register from the programming model. It can be read from and written to via the BDM
port.
Configuration/Status Register (CSR)
Field Definitions:
STATUS[31:28]–Breakpoint Status
This 4-bit field provides read-only status information concerning the hardware breakpoints.
This field is defined as follows:
000x = no breakpoints enabled
001x = waiting for level 1 breakpoint
010x = level 1 breakpoint triggered
101x = waiting for level 2 breakpoint
110x = level 2 breakpoint triggered
The breakpoint status is also output on the DDATA port when not busy displaying other
ColdFire2/2M data. A write to the TDR resets this field.
FOF[27]–Fault-on-Fault
If this read-only status bit is set, a catastrophic halt has occurred and forced entry into BDM.
This bit is cleared on a read from the CSR.
TRG[26]–Hardware Breakpoint Trigger
If this read-only status bit is set, a hardware breakpoint has halted the processor core and
forced entry into BDM. This bit is cleared by reading CSR, or when the processor is
restarted.
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ColdFire2/2M User’s Manual
7-37
Debug Support
HALT[25]–Processor Halt
If this read-only status bit is set, the processor has executed the HALT instruction and forced
entry into BDM. This bit is cleared by reading the CSR, or when the processor is restarted.
BKPT[24]–Breakpoint Assert
If this read-only status bit is set, the BKPTB signal was asserted, forcing the processor into
BDM. This bit is cleared on a read from the CSR, or when the processor is restarted.
IPW[16]–Inhibit Processor Writes to Debug Registers
If set, this bit inhibits any processor-initiated writes to the debug module’s programming
model registers. This bit can only be modified by commands from the external development
system.
MAP[15]–Force Processor References in Emulator Mode
If set, this bit forces the processor to map all references while in emulator mode to a special
address space, TT = $2, TM = $5 (data) or $6 (text). If cleared, all emulator-mode references
are mapped into supervisor code and data spaces.
TRC[14]–Force Emulation Mode on Trace Exception
If set, this bit forces the processor to enter emulator mode when a trace exception occurs.
EMU[13]–Force Emulation Mode
If set, this bit forces the processor to begin execution in emulator mode when a trace
exception occurs. Refer to Section 7.4.1.1 Emulator Mode.
DDC[12:11]–Debug Data Control
This 2-bit field provides configuration control for capturing operand data for display on the
DDATA port. The encoding is:
00 = no operand data is displayed
01 = capture all M-Bus write data
10 = capture all M-Bus read data
11 = capture all M-Bus read and write data
In all cases, the DDATA port displays the number of bytes defined by the operand reference
size, i.e., byte displays 8 bits, word displays 16 bits, and long displays 32 bits (one nibble at
a time across multiple clock cycles.) Refer to Section 7.2.1.7 Begin Data Transfer (PST =
$8 - $A).
UHE[10]-User Halt Enable
This bit selects the CPU privilege level required to execute the HALT instruction.
0 = HALT is a privileged, supervisor-only instruction
1 = HALT is a non-privileged, supervisor/user instruction
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MOTOROLA
Debug Support
BTB[8:9]–Branch Target Bytes
This 2-bit field defines the number of bytes of branch target address to be displayed on the
DDATA outputs. The encoding is
00 = 0 bytes
01 = lower two bytes of the target address
10 = lower three bytes of the target address
11 = entire four-byte target address
Refer to Section 7.2.1.5 Begin Execution of Taken Branch (PST = $5).
NPL[6]–Non-pipelined Mode
If set, this bit forces the processor core to operate in a nonpipeline mode of operation. In this
mode, the processor effectively executes a single instruction at a time with no overlap.
IPI[5]–Ignore Pending Interrupts
If set, this bit forces the processor core to ignore any pending interrupt requests signalled
while executing in single-instruction-step mode.
SSM[4]–Single-Step Mode
If set, this bit forces the processor core to operate in a single-instruction-step mode. While
in this mode, the processor executes a single instruction and then halts. While halted, any
of the BDM commands may be executed. On receipt of the GO command, the processor
executes the next instruction and then halts again. This process continues until the single-
instruction-step mode is disabled.
Reserved - All bits labelled “Reserved” or “0” are currently unused and are reserved for
future use. These bits should always be written as “0”.
7.4.3 Concurrent BDM and Processor Operation
The debug module supports concurrent operation of both the processor and most BDM
commands. BDM commands may be executed while the processor is running, except for
the operations that access processor/memory registers:
• Read/Write Address and Data Registers
• Read/Write Control Registers
For BDM commands that access memory, the debug module requests the ColdFire2/2M’s
internal bus. The processor responds by stalling the instruction fetch pipeline and then
waiting until all current bus activity is complete. At that time, the processor relinquishes the
internal bus to allow the debug module to perform the required operation. After the
conclusion of the debug module bus cycle, the processor reclaims ownership of the bus. By
implementing this scheduling mechanism, the processor can minimize the amount of
intrusion caused by debug module requests.
Under certain conditions, the processor may never grant the processor's internal bus to the
debug module causing the BDM command to never be performed. Specifically, the
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MOTOROLA
Debug Support
processor's internal bus grant may be withheld from the debug module if the processor is
executing a tight loop where the entire loop is contained within one aligned longword.
Examples include:
align 4
label1:
nop
bra.b label1
align 4
label2:
bra.w label2
The solution to this scheduling problem is to force the loop to be aligned ACROSS a
longword boundary. Given this alignment, the processor will always correctly grant the
processor's internal bus to the debug module.
The development system must use caution in configuring the Breakpoint Registers if the
processor is executing. The debug module does not contain any hardware interlocks, so
Motorola recommends that the TDR be disabled while the Breakpoint Registers are being
loaded. At the conclusion of this process, the TDR can be written to define the exact trigger.
This approach guarantees that no spurious breakpoint triggers will occur.
Because there are no hardware interlocks in the debug unit, no BDM operations are allowed
while the CPU is writing the debug registers (DSCLK must be inactive).
7.4.4 Motorola Recommended BDM Pinout
The ColdFire BDM connector is a 26-pin Berg Connector arranged 2x13, shown in Figure
7-9.
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ColdFire2/2M User’s Manual
MOTOROLA
Debug Support
EVELOPER RESERVED2
1
2
4
BKPT
GND
GND
3
DSCLK
5
6
DEVELOPER RESERVE
RESET*
+5V1
7
8
DSI
9
10
12
14
16
18
20
22
24
26
DSO
11
13
15
17
19
21
23
25
PST3*
GND
PST1
PST2
PST0
DDATA3*
DDATA1
DDATA2
GND
DDATA0*
MOTOROLA RESERVED
MOTOROLA RESERVED
GND
CLK_CPU
TEA
VCC_CPU
NOTES: 1. Supplied by target
2. Pins reserved for BDM developer use. Contact developer.
3. * Denotes a vectored signal.
Figure 7-9. Recommended BDM Connector
Table 7-11 shows the correlation between the standard ColdFire connector and the
ColdFire2/2M’s signals.
Table 7-11. BDM Connector Correlation
CONNECTOR
+5V
COLDFIRE2/2M
+5V
CONNECTOR
DSO
COLDFIRE2/2M
DSO
BKPT
BKPTB
GND
GND
CLK_CPU
DDATA0
DDATA1
DDATA2
DDATA3
DSCLK
DSI
CLK
PST0
PST[0]
DDATA[0]
DDATA[1]
DDATA[2]
DDATA[3]
DSCLK
PST1
PST[1]
PST2
PST[2]
PST3
PST[3]
RESET
TEA
MRSTB
MTEAB
DSI
Vcc_CPU
V
DD
7.4.5 Differences Between the ColdFire2/2M BDM and CPU32 BDM
1. DSCLK, BKPT, and DSI need to meet the setup and hold times relative to the rising
edge of the processor clock to prevent the processor from propagating metastable
states.
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MOTOROLA
Debug Support
2. DSO transitions relative to the rising edge of DSCLK only. In the CPU32 BDM, DSO
transitions between serial transfers to indicate to the development system that a
command has successfully completed. The ColdFire BDM does not support this
feature.
3. The development system must note that the DSO is not valid during the first rising
edge of DSCLK. Instead, the first rising edge of DSCLK causes DSO to transmit the
MSB of DSO. A serial transfer is illustrated in Figure 7-3.
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ColdFire2/2M User’s Manual
MOTOROLA
SECTION 8
TEST OPERATION
The ColdFire2/2M test stategy includes:
1. At-speed parallel scan testing via 16 parallel scan chains to provide high fault
coverage
2. The use of an I/O test ring to enable scan testing of the embedded CPU and the
surrounding ASIC logic
3. A methodology to provide testing of the integrated memories connected to the CPU
with a minimal required pinout.
The following sections describe the signals and methodologies for:
• Scan Testing
• Integrated Memory Testing
IDDQ testing can also be performed contingent upon the ability to constrain the design to
avoid conditions that cause high leakage currents.
8.1 SIGNALS REQUIRED TO PERFORM SCAN TEST
This section describes the ColdFire2/2M signals dedicated to the scan testing of the
ColdFire2/2M. These signals are required to be muxed out to package pins. All ColdFire2/
2M signals are unidirectional and synchronous.
8.1.1 Scan Enable (SCAN_ENABLE)
This active-high input signal enables scan testing of the ColdFire2/2M. It forces all internal
flip-flops to be linked together into sixteen parallel scan chains.
8.1.2 Scan Exercise Array (SCAN_XARRAY)
This active-high input signal is used to exercise the integrated memory arrays during scan
testing. This signal causes random writes to the internal RAMs by strobing the write strobes
while scanning. The array output data does not affect the scan via use of the SCAN_MODE
pin.
8.1.3 Scan Input (SI[15:0])
These input signals are connected to the16 internal ColdFire2/2M scan chain inputs.
MOTOROLA
ColdFire2/2M User’s Manual
8-1
Test Operation
8.1.4 Scan Mode (SCAN_MODE).
This active-high, unidirection input signal gates off all memory array outputs during scan
testing.SCAN_MODE must be asserted for the duration of scan testing.
8.1.5 Scan Output (SO[15:0])
These output signals are connected to the 16 internal ColdFire2/2M scan chain outputs.
8.1.6 I/O Test Ring Clock (TRCLK)
This input signal is the synchronous clock used to transition the test ring during scan testing.
TR_CLK is connected to the clock input of all I/O test ring registers.
8.1.7 I/O Test Ring Core Mode Enable (CORE_TEST)
This active-high input signal enables the core mode of the test ring during scan testing. The
test ring is in scan core mode if CORE_TEST is asserted and in scan ASIC mode if
CORE_TEST is negated.
8.1.8 I/O Test Ring Data Input (TR_SDI[1:0])
These input signals are the serial data inputs for the I/O test ring chains.
8.1.9 I/O Test Ring Data Output (TR_SDO[1:0])
These output signals are the serial output data from the I/O test ring chains.
8.1.10 I/O Test Ring Enable (TR_SE)
This active-high input signal enables the test ring. TR_SE is connected to the scan enable
input of all I/O test ring scannable registers.
8.1.11 I/O Test Ring Mode (TR_MODE)
This active-high input signal enables the scan test mode of the test ring. The test ring is in
scan test mode if TR_MODE is asserted and in normal functional mode if negated.
TR_MODE should be asserted for the duration of scan testing, and be held negated for the
duration of memory testing and during functional operation of the device.
8.1.12 TEST WRITE INHIBIT (TEST_WR_INH).
Optional: Asserting this signal will prevent strobing; i.e. writing, of any of the integrated
memories. However, as long as SCAN_MODE is asserted, the array outputs are gated off
from the ColdFire2/2M and will not affect the scan vectors.
8.2 SCAN OPERATION
Motorola provides ATPG vectors for the ColdFire2/2M. The signals listed in the previous
section must be brought out to package pins (muxed out) in order for Motorola supplied scan
vectors to be applied. This section provides an understanding of the ColdFire2/2M scan
implementation. The following diagram illustrates the ColdFire2/2M scan test
implementation:
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
S1[15:0]
SO[15:0]
TR_SDO[1:0]
OUTPUT
INPUT
OUTPUT
INPUT
OUTPUT
INPUT
OUTPUT
INPUT
TR_SDI[1:0]
TEST RING
CF2 CPU
COLDFIRE2/2M
Figure 8-1. Scan Test Implementation Diagram
SI/SO refer to the 16 parallel scan chains that cover the registers in ColdFire2/
2M.SCAN_EN controls these chains. If these pins, plus all other inputs and outputs of
ColdFire2/2M were muxed to package pins, ATPG coverage of the core would be enabled.
The I/O test ring allows stimulus to be applied to embedded ColdFire2/2M inputs and allows
ColdFire2/2M embedded outputs to be observed with a minimum of pins muxed to the chip
periphery. SI[15:0] is used to load the ColdFire2/2M parallel scan chains while TR_SDI[1:0]
set up the appropriate values on the ColdFire2/2M inputs for each scan vector. SO[15:0] and
TR_SDO[1:0] are used to observe and verify the scan behavior.
The I/O test ring isolates the ASIC logic from the ColdFire2/2M enabling separate scan
testing of each. It is comprised of two scan chains, each containing 44 registers (half
scannable, half not; see Table 8-3, Table 8-4 and Figure 8-2). The heads of the chains are
TR_SDI[0] and TR_SDI[1]. The tails of the chains are TR_SDO[0] and TR_SDO[1]. The I/O
test ring also enables input and output spec testing as follows: the clocks (TR_CLK and
CLK) can be skewed to verify that a transition launched from the scan ring is captured at the
input register in a specified period of time. This is then verified by capturing outputs of the
ColdFire2/2M and shifting the scan data out to compare to expected values. This is also how
output specs are verified: the clocks can be skewed a specified amount, and an output
transition can be captured by the scan ring. Again, the data is shifted out and values
compared to expected values. See Table 8-1 for scan chain I/O and length information.
MOTOROLA
ColdFire2/2M User’s Manual
8-3
Test Operation
In functional mode, the I/O test ring adds a 2:1 multiplexor delay to the inputs and outputs
of the core. Each cell in the I/O test ring pairs an input and an output which allows for the
sharing of registers.
TRSDI
TRSDO
ASIC
CF2 CORE
CORE_IN
ASIC_OUT
0
1
FF1
FF2
CK
0
1
D
Q
D
Q
SDI
SE
CK
0
CORE_OUT
ASIC_IN
1
CORE_TEST
TR_SE
TRCLK
TR_MODE
Figure 8-2. I/O Test Ring Cell
Table 8-1. Parallel Scan Chain Information
SCAN CHAIN
DESIGNATOR
SCAN CHAIN SCAN CHAIN
LENGTH
INPUT
OUTPUT
SO[15]
SO[14]
SO[13]
SO[12]
SO[11]
SO[10]
SO[9]
0
SI[0]
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
84
88
88
1
SI[1]
2
SI[2]
3
SI[3]
4
SI[4]
5
SI[5]
6
SI[6]
7
SI[7]
SO[8]
8
SI[8]
SO[7]
9
SI[9]
SO[6]
10
SI[10]
SI[11]
SI[12]
SI[13]
SI[14]
SI[15]
TRSDI[0]
TRSDI[1]
SO[5]
11
SO[4]
12
SO[3]
13
SO[2]
14
SO[1]
15
SO[0]
I/O TEST RING 0
I/O TEST RING 1
TRSDO[0]
TRSDO[1]
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
The I/O test ring behaves in the same manner for the ASIC logic as it does for ColdFire2/
2M. Table 8-2 lists the I/O test ring control signal configurations for the different modes of
testing. Table 8-3 and Table 8-4 list each signal, which I/O test ring chain it is part of, and
how deep (how many cells from TRSDI[1:0] it is in the chain. Note that an X means that the
signal needs to be driven, however high or low is optional. The actual value is a don’t care.
Table 8-2. I/O TEST RING MODE CONFIGURATioNS
FUNCTIONAL
SCAN
ColdFire2/2M ASIC
SCAN
LOAD
SHIFT OUT
(NON-SCAN)
CORE_TEST
TR_SE
*X
1
0
0
0
*X
1
*X
*X
*X
0
1
TRCLK
ON
*X
ON
1
ON
1
ON
*X
*X
TR_MODE
TR_SDI[1:0]
APPLY DATA
*X
*X
*X
* Needs to driven high or low. The actual value is a don’t care.
Table 8-3. I/O TEST RING CHAIN 0 (TRSDI[0]/TRSDO[0])
CELL #
CELL #
CORE INPUT
CORE OUTPUT
CORE INPUT CORE OUTPUT
(2 REGS/
CELL)
(2 REGS/
CELL)
MRDATA_IE
MWDATA_OE HEAD OF I/O MRDATA[21]
MWDATA[21]
23
TEST RING
CHAIN 0
MRDATA[0]
MRDATA[1]
MRDATA[2]
MRDATA[3]
MRDATA[4]
MRDATA[5]
MRDATA[6]
MRDATA[7]
MRDATA[8]
MRDATA[9]
MRDATA[10]
MRDATA[11]
MRDATA[12]
MRDATA[13]
MRDATA[14]
MRDATA[15]
MRDATA[16]
MRDATA[17]
MRDATA[18]
MRDATA[19]
MRDATA[20]
MWDATA[0]
MWDATA[1]
MWDATA[2]
MWDATA[3]
MWDATA[4]
MWDATA[5]
MWDATA[6]
MWDATA[7]
MWDATA[8]
MWDATA[9]
MWDATA[10]
MWDATA[11]
MWDATA[12]
MWDATA[13]
MWDATA[14]
MWDATA[15]
MWDATA[16]
MWDATA[17]
MWDATA[18]
MWDATA[19]
MWDATA[20]
2
3
MRDATA[22]
MRDATA[23]
MRDATA[24]
MRDATA[25]
MRDATA[26]
MRDATA[27]
MRDATA[28]
MRDATA[29]
MRDATA[30]
MRDATA[31]
MTEAB
MWDATA[22]
MWDATA[23]
MWDATA[24]
MWDATA[25]
MWDATA[26]
MWDATA[27]
MWDATA[28]
MWDATA[29]
MWDATA[30]
MWDATA[31]
MKILLB
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
IPLB[0]
MTM[0]
IPLB[1]
MTM[1]
IPLB2]
MTM[2]
ICH_SZ[0]
PST[0]
ICH_SZ[1]
PST[1]
ICH_SZ[2]
PST[2]
SRAM_SZ[0]
SRAM_SZ[1]
SRAM_SZ[2]
ROM_SZ[2]
DDATA[0]
DDATA[1]
DDATA[2]
TEST_RHIT
TAIL OF I/O
TEST RING
CHAIN 0
MOTOROLA
ColdFire2/2M User’s Manual
8-5
Test Operation
Table 8-4. I/O TEST RING CHAIN 1 (TRSDI[1]/TRSDO[1])
CELL #
CELL #
CORE INPUT
CORE OUTPUT
CORE INPUT CORE OUTPUT
(2 REGS/
CELL)
(W REGS/
CELL)
NC
mfrzb
HEAD OF I/O
TEST RING
CHAIN 1
TEST_CTRL
MADDR[18]
23
MRDATA[0]
ROM_SZ[0]
MARBC[0]
MARBC[1]
PST[3]
2
3
TEST_RD
TEST_DATA_RD
TEST_RAM_RD
TEST_ROM_RD
ROM_VLD
MADDR[19]
MADDR[20]
MADDR[21]
MADDR[22]
MADDR[23]
MADDR[24]
MADDR[25]
MADDR[26]
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
ROM_SZ[1]
4
MRSTB
DDATA[3]
DSO
5
DSCLK
6
IACK_68k
MRW
7
TEST_IVLD_INH
NC
TEST_MODE
TEST_KTA
MTT[0]
8
MTT[1]
9
NC
TEST_ADDR[2]
TEST_ADDR[3]
TEST_ADDR[4]
TEST_ADDR[5]
TEST_ADDR[4]
TEST_ADDR[7]
TEST_ADDR[8]
TEST_ADDR[9]
TEST_ADDR[10]
TEST_ADDR[11]
TEST_ADDR[12]
TEST_ADDR[13]
TEST_ADDR[14]
MADDR[5]
MADDR[6]
MADDR[7]
MADDR[8]
MADDR[9]
MADDR10]
MADDR[11]
MADDR[12]
MADDR[13]
MADDR[14]
MADDR[15]
MADDR[16]
MADDR[17]
10
11
12
13
14
15
16
17
18
19
20
21
22
TEST_ITAG_WRT MADDR[27]
TEST_DATA_WRT MADDR[28]
TEST_RAM_WRT MADDR[29]
MTAB
BKPTB
NC
MADDR[30]
MADDR[31]
MADDR[0]
MADDR[1]
MADDR[2]
MADDR[3]
MADDR[4]
MSIZ[0]
NC
NC
NC
NC
NC
NC
MSIZ[1]
NC
MTSB
TAIL OF I/O
TEST RING
CHAIN 1
8.3 INTEGRATED MEMORY TESTING
A test mode is provided to test embedded SRAM, ROM, and/or ICACHE arrays that connect
directly to the ColdFire2/2M. All integrated memories are tested by placing the ColdFire2/
2M into test mode (TEST_MODE = 1) and performing reads and writes via the test bus and
system-bus. These busses allow external access to the integrated memories via functional
paths. The path from the test/system bus to the memory arrays is a pipelined path. The test
bus input signals serve as multiplexor select signals to enable the correct path from
MRDATA and TEST_ADDR to a particular array, and from the particular array out through
MWDATA. During test mode, ColdFire2/2M is idle and does not execute code.
The following section details the signal descriptions, test methodology, and data transfer
mechanisms.
8.3.1 Test Bus Signal Description
This section describes the ColdFire2/2M signals dedicated to testing the integrated
memories. Additional signals are required to be either asserted or negated during memory
test and are described here also. If all three types of integrated memories are used; ie.
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Test Operation
SRAM, ROM, and ICACHE, all signals listed here must be brought out to package pins via
muxing. If only one or two types of integrated memories are used, a subset of signals listed
here must be brought out to package pins. I.E. some of the test input control pins could be
negated instead of needing to be muxed out. Also, depending upon array size, not all of
TEST_ADDR may be necessary. All ColdFire2/2M signals are unidirectional and
synchronous.
8.3.1.1 TEST ADDRESS BUS (TEST_ADDR[14:2]). These input signals are used to
specify an address when testing the integrated memories.
8.3.1.2 TEST CONTROL (TEST_CTRL). This active-high input signal indicates the test
address bus (TEST_ADDR[14:2]) will be latched on the next positive clock edge.
8.3.1.3 TEST IDATA READ (TEST_IDATA_RD). This active-high input signal is used to
test the instruction cache data memory read operation.
8.3.1.4 TEST IDATA WRITE (TEST_IDATA_WRT). This active-high input signal is used to
test the instruction cache data memory write operation.
8.3.1.5 TEST INSTRUCTION CACHE READ HIT (TEST_RHIT). This active-high output
signal indicates a hit has occurred when accessing the instruction cache during memory
array testing.
8.3.1.6 TEST INVALIDATE INHIBIT (TEST_IVLD_INH). This active-high input signal
inhibits the invalidate operation when testing the instruction cache.
8.3.1.7 TEST ITAG WRITE (TEST_ITAG_WRT). This active-high input signal is used to
test the instruction cache tag memory write operation.
8.3.1.8 TEST KTA MODE ENABLE (TEST_KTA). This active-high input signal allows the
instruction cache tag and data arrays to be read in parallel, mimicking the functional
operation. This allows testing of the speed path from the tag and data arrays to the core.
8.3.1.9 TEST MODE ENABLE (TEST_MODE). This active-high input signal is used to
enable all of the integrated memory test signals. TEST_MODE should be asserted for the
duration of memory testing.
8.3.1.10 TEST SRAM READ (TEST_SRAM_RD). This active-high input signal is used to
test the integrated SRAM memory read operation.
8.3.1.11 TEST SRAM WRITE (TEST_SRAM_WRT). This active-high input signal is used
to test the integrated SRAM memory write operation.
8.3.1.12 TEST READ (TEST_RD). This active-high input signal is used to test read
operations on all of the integrated memories.
8.3.1.13 TEST ROM READ (TEST_ROM_RD). This active-high input signal is used to test
the integrated ROM memory read operation.
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ColdFire2/2M User’s Manual
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Test Operation
8.3.1.14 TEST WRITE INHIBIT (TEST_WR_INH). This active-high input signal disables
the write strobes to the SRAM and instruction cache compiled RAMS. TEST_WR_INH
should be negated for the duration of memory test.
8.3.1.15 MIE. This active-high input signal enables the capturing of MRDATA into the
memory arrays. MIE should be asserted for the duration of memory testing.
8.3.1.16 TR_MODE. This signal needs to be negated to keep the I/O test ring in functional
mode. TR_MODE should be negated for the duration of memory testing.
8.3.1.17 MWDATA[31:0]. The M-Bus write data bus is used to observe array data during
array reads.
8.3.1.18 MRDATA[31:0].The M-Bus read data bus is used to apply write data during array
writes.
8.3.1.19 SCAN_MODE. This signal must be negated to allow array output data into the
ColdFire2/2M.
8.3.1.20 SCAN_SE. This signal must be negated to allow functional operation of the
ColdFire2/2M.
8.3.1.21 SCAN_XARRAY. This signal should be negated to prevent continuous strobing of
the ColdFire2/2M integrated memories.
8.3.2 Memory Test Theory of Operation
A write consists of 4 cycles; i.e. it is not until the fourth cycle after applying TEST_ADDR and
MRDATA, with the array’s write control signal active, that data is strobed into the array. Data
and address can be updated continuously every cycle to fill the array via the pipeline.
A read consists of 6 cycles; i.e. it is not until the sixth cycle after applying TEST_ADDR, with
the array’s read control signal active, that data appears on MWDATA. Address can be
updated continuously every cycle to read the array via the pipeline.
Both the SRAM and ICACHE DATA arrays are accessed as noted above. The ROM is read
as noted above. Two test modes exist for the ICACHE TAG array. Essentially the TAG and
DATA array are written. Leaving TEST_MODE asserted, TEST_KTA is then asserted and
address applied. TEST_RHIT will be asserted 4 cycles later, ICACHE DATA array data will
subsequently appear on MWDATA 2 cycles later.
The processor must be placed in reset in accordance with the system reset specification.
The sequence (MRSTB asserted 6 cycles, stall 8cycles) must be executed both upon
entering test mode at power-up, as well as when switching into test mode from any other
mode. It is this sequence that directs the CPU to go into an idle mode to allow integrated
memory testing.
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Test Operation
8.3.3 Test Mode
The test mode is entered by asserting TEST_MODEand MIE, negating TEST_CTRL,
TEST_WR_INH, and TR_MODE, and resetting the ColdFire2/2M as described in Section
3.9 Reset Operation. MRSTB must be asserted (low) >= 6 cycles. The first test sequence
should not begin until at least eight clock cycles after MRSTB is negated. TEST_MODE and
MIE should remain asserted during all test sequences. TEST_WR_INH and TR_MODE
should remain negated during all test sequences.
8.3.4 Instruction Cache Tag RAM Testing
The instruction cache tag RAM consists of up to 2K addresses that can be accessed
individually through the test bus. Testing the compiled tag RAM is accomplished by first
writing into the tag RAM to set the valid bit, and reading the tag RAM to check for a cache hit.
8.3.4.1 INSTRUCTION CACHE TAG RAM WRITE FUNCTION. Writing to the instruction
cache tag RAM is performed though the test bus and MRDATA[31:0] after entering test
mode. The address and control signals are input on the test bus and the data to be written
to the tag RAM is input on MRDATA[31:0].
Writes to the tag RAM are performed in a pipelined fashion as shown in Figure 8-3. All input
signals are latched on the positive edge of CLK and all outputs transition on the positive
edge of CLK.
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ColdFire2/2M User’s Manual
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Test Operation
C1
A0
C2
C3
C4
C5
CN
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
MRDATA
A1
D0
A2
D1
A3
D2
A4
D3
A0
A5
D4
A1
TEST_ITAG_WRT
ICH_ADDR
ICHT_CSB
ICHT_RWB
ICHT_DI
T0
T1
ICHT_ST
Figure 8-3. Test Instruction Cache Tag Write Cycles
Clock 1 (C1)
On the first clock cycle of the tag RAM write sequence, the first tag RAM address should be
driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the first data value associated with the address asserted in C1 should
be driven onto MRDATA[31:0] and the next address should be driven onto
TEST_ADDR[14:2].
Clock 3 (C3)
On the third cycle, the next address and data values should be driven.
Clock 4 (C4)
On the fourth cycle, the next address and data values should be driven and
TEST_ITAG_WRT should be asserted. The remaining addresses and data are driven each
successive clock cycle and TEST_ITAG_WRT should remain asserted until the last data
value has been latched.
Clock 5 (C5)
The fifth clock cycle is identical to C4. The first write to the tag RAM occurs.
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MOTOROLA
Test Operation
Clock n (Cn)
The remaining clock cycles in the test are identical to C5.
Throughout the entire sequence, the data value being driven is associated with the address
driven in the previous clock cycle. The format of the data value written to the tag RAM
depends on the cache configuration. The data value consists of the significant upper bits
latched on MRDATA with the valid bit (bit eight) set. See Section 5.1 Instruction Cache for
more information.
8.3.4.2 INSTRUCTION CACHE TAG RAM READ FUNCTION. Reading from the
instruction cache tag RAM is not performed as a typical input address, read data operation.
Instead, reading the instruction cache tag RAM is performed though the test bus and
MRDATA[31:0] after entering test mode. The address and control signals are input on the
test bus and the expected value of the data from the tag RAM is input on MRDATA[31:0].
Reads from the tag RAM are performed in a pipelined fashion as shown in Figure 8-4. All
input signals are latched on the positive edge of CLK and all outputs transition on the
positive edge of CLK.
C1
A0
C2
C3
C4
A3
CN
A4
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
MRDATA
A1
D0
A2
D1
D2
A0
D3
A1
ICH_ADDR
ICHT_CSB
ICHT_RWB
ICHT_ST
ICHT_DO
T0
T1
TEST_RHIT
Figure 8-4. Test Instruction Cache Tag Read Cycles
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ColdFire2/2M User’s Manual
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Test Operation
Clock 1 (C1)
On the first clock cycle of the tag RAM read sequence, the first data RAM address should
be driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the first expected data value associated with the address asserted in
C1 should be driven onto MRDATA[31:0] and the next address should be driven onto
TEST_ADDR[14:2]. The remaining addresses and expected data are driven each
successive clock cycle.
Clock 3 (C3)
The third clock cycle is identical to C2.
Clock 4 (C4)
The fourth clock cycle is identical to C3. The first read from the tag RAM occurs in C4, three
cycles after the first address was driven. If the value read from the tag RAM is equal to the
associated value latched on MRDATA[31:0] and the valid bit is set, TEST_RHIT will be
asserted.
Clock n (Cn)
The remaining clock cycles in the test are identical to C4.
Throughout the entire sequence, TEST_RHIT is associated with the address driven three
clock cycles earlier. For this reason, three stall cycles (TEST_CTRL negated) should occur
after the last address is driven before the next sequence to wait for the last TEST_RHIT.
8.3.4.3 INSTRUCTION CACHE TAG RAM WRITE FOLLOWED BY READ FUNCTION.
The following timing diagram illustrates the minimum number of cycles necessary to perform
a write followed by read of the instruction cache tag RAM. A certain sequence is neccessary
because of the pipelined datapath to the arrays from MRDATA and MWDATA.
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MOTOROLA
Test Operation
.
C1
C2
C3
C4
C5
C6
C7
C8
C9
CLK
TEST_MODE
TEST_CTRL
TEST_ITAG_WRT
TEST_RD
A1
A2
D1
A3
D2
A1
A2
A3
TEST_ADDR
D2
D3
D1
MRDATA
TEST_RHIT
A2
D2
D2
A1
D1
D1
ICHT_ADDR
ICHT_DI
ICHT_DO
RD
READ
WR
WRITE
STALL
STALL
Figure 8-5. I-Cache Tag Write Followed by Read
Clock 1 (C1)
On the first clock cycle , the data RAM address A1 should be driven onto TEST_ADDR[14:2]
and TEST_ITAG_WRT should be asserted.
Clock 2 (C2)
On the second cycle, the D1, data value associated with the address asserted in C1, should
be driven onto MRDATA[31:0]. The address value driven in C1, A1, can optionally be driven
in C2. TEST_ITAG_WRT remains asserted.
Clock 3 (C3)
The third clock cycle is a stall cycle necessary because of the pipelined data path. The
address driven in C1, A1, must be driven during C3.TEST_ITAG_WRT remains asserted.
Clock 4 (C4)
The next write address, A2, should be driven onto TEST_ADDR[14:2] during C4. The data
driven in C2, D1, must be driven in C4.TEST_ITAG_WRT remains asserted.
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ColdFire2/2M User’s Manual
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Test Operation
Clock 5(C5)
TEST_ITAG_WRT must be negated during C5. A1 and D1, associated with C1/C2, are at
the ICACHE tag array during C5; i.e. the actual WRITE to the array occurs in this cycle. The
data value associated with the address asserted in C4, D2, is driven onto MRDATA[31:0]
during this cycle as well. You have the option of driving A2 during this cycle.
Clock 6 (C6)
The TEST_RHIT signal will assert during this cycle if the ICACHE tag array data for A1
matches D1, the access in Cycles C1 and C2; i.e. it is in this cycle that the actual READ
occurs. A2 must be driven onto TEST_ADDR[14:2] during this cycle. TEST_ITAG_WRT
asserts and D2 can optionally be driven during this cycle.
Clock 7 (C7)
On C7, D2, must be driven onto MRDATA[31:0] and the next data RAM address, A3, should
be driven onto TEST_ADDR[14:2]. This is a stall cycle. TEST_ITAG_WRT remains asserted
during this cycle.
Clock 8 (C8)
During C8, TEST_ITAG_WRT must be negated. A3 can optionally be driven during this
cycle; D3 must be driven during this cycle. The actual write of A2/D2 occurs during this
cycle.
This periodic 3-cycle sequence continues; ie. C4-C6 are repeated during C7-C9, C10-C12,
etc. These three cycles are STALL, WRITE, then READ. TEST_ITAG_WRT always negates
during the “C5” cycle or the WRITE cycle and asserts during the “C6-C7” cycles..
TEST_RHIT always asserts if no error during “C6” or the READ cycle. The address is
asserted in the “C4” cycle, optionally asserted in the “C5” cycle and again asserted during
the “C6” cycle. The corresponding data to that address is driven in “C5”, optionally driven in
“C6” and then driven again in “C7”.
8.3.5 Instruction Cache Data RAM Testing
The instruction cache data RAM consists of up to 8K long words that can be accesses
individually through the test bus. Testing the compiled data RAM is accomplished by first
writing test patterns into the data RAM, reading the data RAM, and verifying the results.
8.3.5.1 INSTRUCTION CACHE DATA RAM WRITE FUNCTION. Writing to the instruction
cache data RAM is performed though the test bus and MRDATA[31:0] after entering test
mode. The address and control signals are input on the test bus and the data to be written
to the data RAM is input on MRDATA[31:0].
Writes to the data RAM are performed in a pipelined fashion as shown in Figure 8-6. All input
signals are latched on the positive edge of CLK and all outputs transition on the positive
edge of CLK.
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MOTOROLA
Test Operation
C1
A0
C2
C3
C4
CN
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
MRDATA
A1
D0
A2
D1
A3
D2
A0
A4
D3
A1
TEST_IDATA_WRT
ICH_ADDR
ICHD_CSB
ICHD_RWB
ICHD_DI
D0
D1
ICHD_ST
Figure 8-6. Test Instruction Cache Data Write Cycles
Clock 1 (C1)
On the first clock cycle of the data RAM write sequence, the first data RAM address should
be driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the first data value associated with the address asserted in C1 should
be driven onto MRDATA[31:0] and the next address should be driven onto
TEST_ADDR[14:2].
Clock 3 (C3)
On the third cycle, the next address and data values should be driven and
TEST_IDATA_WRT should be asserted.
Clock 4 (C4)
The fourth clock cycle is identical to C3. The remaining addresses and data are driven each
successive clock cycle and TEST_IDATA_WRT should remain asserted until the last data
value has been latched. The first write to the data RAM occurs.
Clock n (Cn)
The remaining clock cycles in the test are identical to C4.
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ColdFire2/2M User’s Manual
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Test Operation
Throughout the entire sequence, the data value being driven is associated with the address
driven in the previous clock cycle.
8.3.5.2 INSTRUCTION CACHE DATA RAM READ FUNCTION. Reading from the
instruction cache data RAM is performed though the test bus and MWDATA[31:0] after
entering test mode. The address and control signals are input on the test bus and the data
from the data RAM is output on MWDATA[31:0].
Reads from the data RAM are performed in a pipelined fashion as shown in Figure 8-7. All
input signals are latched on the positive edge of CLK and all outputs transition on the
positive edge of CLK.
C1
A0
C2
A1
C3
A2
C4
A3
C5
A4
C6
A5
CN
A6
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
TEST_IDATA_RD
TEST_RD
ICH_ADDR
ICHD_CSB
A0
A1
A2
A3
ICHD_RWB
ICHD_ST
ICHD_DO
D0
D1
D2
D0
D3
D1
MWDATA
Figure 8-7. Test Instruction Cache Data Read Cycles
Clock 1 (C1)
On the first clock cycle of the data RAM read sequence, the first data RAM address should
be driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the next addresses should be driven onto TEST_ADDR[14:2].
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MOTOROLA
Test Operation
Clock 3 (C3)
The third cycle is identical to C2.
Clock 4 (C4)
On the fourth cycle, the next address should be driven and TEST_IDATA_RD should be
asserted. The first read from the data RAM occurs in C4.
Clock 5 (C5)
On the fifth cycle, the next address should be driven and TEST_RD should be asserted. The
remaining addresses are driven each successive clock cycle and TEST_IDATA_RD should
remain asserted until the last data value has been read from the data RAM.
Clock 6 (C6)
Cycle 6 is identical to C5. The MWDATA[31:0] signals are driven with the first data, five
cycles after the associated address was driven. TEST_RD should remain asserted until the
last data value has been driven onto MWDATA[31:0].
Clock n (Cn)
The remaining clock cycles in the test are identical to C6.
Throughout the entire sequence, the data value being driven is associated with the address
driven five clock cycles earlier. For this reason, five stall cycles (TEST_CTRL negated)
should occur after the last address is driven before the next sequence to wait for the last
data to be driven.
8.3.5.3 INSTRUCTION CACHE DATA RAM WRITE FOLLOWED BY READ FUNCTION.
The following timing diagram illustrates the minimum number of cycles necessary to perform
a write followed by read of the instruction cache data RAM. A certain sequence is
neccessary because of the pipelined datapath to the arrays from MRDATA and MWDATA.
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MOTOROLA
Test Operation
C1
C2
A1
C3
C4
A2
C5
C6
A3
C7
C8
A4
C9
TEST_ADDR
D4
MRDATA
D2
D1
D3
TEST_IDATA_RD
TEST_RD
TEST_IDATA_WRT
MWDATA
D1
D2
ICHT_ADDR
ICHD_DI
A1
A2
A3
D1
D3
D2
D1
D3
D2
ICHD_DO
WRITE READ WRITE READ WRITE READ
Figure 8-8. I-Cache Data Write/Read
Clock 1 (C1)
On the first clock cycle , A1 (data RAM address) should be driven onto TEST_ADDR[14:2]
and TEST_IDATA_WRT should be asserted.
Clock 2 (C2)
On the second cycle, D1 (the data value associated with A1, the address asserted in C1)
should be driven onto MRDATA[31:0]. A1 must continue to be driven during this cycle.
TEST_IDATA_WRT continues to be asserted.
Clock 3 (C3)
On the third cycle, the next data RAM address, A2, is driven onto TEST_ADDR[14:2]. D1
can optionally be driven during this cycle. TEST_IDATA_WRT remains asserted during this
cycle.
Clock 4 (C4)
D2 should be driven onto MRDATA[31:0] during this cycle. TEST_IDATA_RD must be
asserted here for the length of this test. TEST_IDATA_WRT is negated during this cycle.
The actual WRITE to the ICACHE data array of the C1/C2 (A1/D1) access occurs during this
cycle. A2 must remain driven during this cycle.
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MOTOROLA
Test Operation
Clock 5(C5)
The next data RAM address, A3, should be driven onto TEST_ADDR[14:2] during this cycle.
TEST_RD is asserted here for the length of this test. TEST_IDATA_WRT is asserted during
this cycle. The acutal READ of the ICACHE data array C1/C2 (A1/D1) access occurs during
this cycle. D2 can optionally be driven during this cycle.
Clock 6 (C6)
D3, the data associated with the C5 address, A3, is driven onto MRDATA[31:0] during this
cycle. TEST_IDATA_WRT is negated during this cycle .The actual WRITE of the ICACHE
data access C3/C4 (A2/D2) occurs during this cycle. A3 must remain driven in this cycle.
Clock 7 (C7)
A4 should be driven onto TEST_ADDR[14:2] during this cycle. TEST_IDATA_WRT is
asserted. The C1/C2 access read data, D1, will be driven onto MWDATA[31:0] during this
cycle. The actual READ of the ICACHE data array C3/C4 access (A2/D2) occurs during this
cycle. D3 can optionally be driven in this cycle.
Clock 8 (C8)
D4 must be driven onto MRDATA[31:0] during this cycle. A4 must remain driven.
TEST_IDATA_WRT is negated. The actual WRITE of the ICACHE data array C3/C4
access, A3/D, occurs here.
Clock 9 (C9)
A5 must be driven onto TEST_ADDR[14:2] during this cycle. TEST_IDATA_WRT is
asserted. D4 can optionally be driven in this cycle. The C5/C6 access read data, D2, will be
driven onto MWDATA[31:0] during this cycle. The actual READ of the ICACHE data array
C5/C6 access (A3/D3) occurs during this cycle.
This periodic 2-cycle sequence continues; ie. C6-C7 are repeated during C8-C9, C10-C11,
etc. The “C6” cycle is the actual WRITE cyle and the “C7” cycle is the actual READ cycle
where the data from the previous actual WRITE/READ sequence is displayed on MWDATA.
8.3.6 Instruction Cache KTA Mode Testing
The KTA mode tests the read data path for both of the instruction cache (tag and data)
RAMs. This test checks the valid bit and performs a compare between the upper bits of the
appropriate tag and the upper bits of the address to determine a cache hit. If the read is a
hit, the value from the data RAM is returned. This mimicks the reading of the instruction
cache during normal operation. Both RAMs are first written using instruction cache data and
tag write cycles.
Both the MRDATA[31:15] signals and part of the TEST_ADDR[14:2] signals are used to
drive data into the array and compare against during the read.
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MOTOROLA
Test Operation
A 512 byte ICACHE array uses an ICACHE tag array sized 32x24; thus having 5 address
bits. TEST_ADDR[8:4] is used to address the tag array, while TEST_ADDR[8:2] addresses
the ICACHE data array (128x32). {MRDATA[31:15], TEST_ADDR[14:9]} is used to compare
data to the tag array. These 23 bits compare to the 23 bits of address in the tag array, the
24th bit is the valid bit.
Table 8-5. TEST KTA CONFIGURATioNS
ICACHE SZ
BYTES
TAG ARRAY SZ TAG ARRAY
TEST_ADDR
MRDATA & TEST_ADDR
LOCATIONS X #
ADDR BITS
USED TO ADDR
USED FOR DATA WRITES/CMPRS
OF DATA BITS
512
1K
32x24
64x23
5
6
TEST_ADDR[8:4]
TEST_ADDR[9:4]
TEST_ADDR[10:4]
TEST_ADDR[11:4]
TEST_ADDR[12:4]
TEST_ADDR[13:4]
TEST_ADDR[14:4]
{MRDATA[31:15], TEST_ADDR[14:9]}
{MRDATA[31:15], TEST_ADDR[14:10]}
{MRDATA[31:15], TEST_ADDR[14:11]}
{MRDATA[31:15], TEST_ADDR[14:12]}
{MRDATA[31:15], TEST_ADDR[14:13]}
{MRDATA[31:15], TEST_ADDR[14]}
MRDATA[31:15]
2K
128x22
256x21
512x20
1Kx19
2Kx18
7
4K
8
8K
9
16K
32K
10
11
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
C1
A0
C2
C3
C4
C5
C6
CN
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
MRDATA
A1
T0
A2
T1
A3
T2
A4
T3
A5
T4
A6
T5
TEST_KTA
TEST_IDATA_RD
TEST_RD
ICH_ADDR
ICHT_CSB
ICHT_RWB
ICHT_ST
A0
T0
D0
A1
T1
D1
A2
A3
ICHT_DO
T2
T3
ICHD_CSB
ICHD_RWB
ICHD_ST
ICHD_DO
D2
D0
D3
D1
TEST_RHIT
MWDATA
Figure 8-9. KTA Mode Cycles
Clock 1 (C1)
On the first clock cycle of the KTA mode sequence, the first data RAM address should be
driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
Clock 2 (C2)
On the second cycle, the next data RAM addresses should be driven onto
TEST_ADDR[14:2]. The MRDATA[31:8] signals should be driven with the tag information
expected from the tag RAM for the line associated with the address driven in C1.
Clock 3 (C3)
The third cycle is identical to C2.
Clock 4 (C4)
On the fourth cycle, the next address should be driven, TEST_KTA should be asserted, and
TEST_IDATA_RD should be asserted. The first read from the cache RAMs occur in C4. If
the value from the tag RAM is equal to the tag value driven in C2, TEST_RHIT will be
asserted.
Clock 5 (C5)
On the fifth cycle, the next address should be driven and TEST_RD should be asserted. The
remaining addresses are driven each successive clock cycle and TEST_KTA and
TEST_IDATA_RD should remain asserted until the last data value has been read from the
data RAM.
Clock 6 (C6)
Cycle 6 is identical to C5. The MWDATA[31:0] signals are driven with the first data, five
cycles after the associated address was driven. TEST_RD should remain asserted until the
last data value has been driven onto MWDATA[31:0].
Clock n (Cn)
The remaining clock cycles in the test are identical to C6.
8.3.7 ROM Testing
The ROM consists of up to 8K long words that can be accesses individually through the test
bus. Testing the compiled ROM is accomplished by reading the ROM and verifying the
results.
8.3.7.1 ROM READ FUNCTION. Reading from the ROM is performed though the test bus
and MWDATA[31:0] after entering test mode. The address and control signals are input on
the test bus and the data from the ROM is output on MWDATA[31:0].
Reads from the ROM are performed in a pipelined fashion as shown in Figure 8-10. All input
signals are latched on the positive edge of CLK and all outputs transition on the positive
edge of CLK.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
C1
A0
C2
A1
C3
A2
C4
A3
C5
A4
C6
A5
CN
A6
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
TEST_ROM_RD
TEST_RD
ROM_ADDR
ROM_CSB
A0
D0
A1
D1
A2
A3
ROM_ENB
ROM_DO
D2
D0
D3
D1
MWDATA
Figure 8-10. Test ROM Read Cycles
Clock 1 (C1)
On the first clock cycle of the ROM read sequence, the first ROM address should be driven
onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the next addresses should be driven onto TEST_ADDR[14:2].
Clock 3 (C3)
The third cycle is identical to C2.
Clock 4 (C4)
On the fourth cycle, the next address should be driven and TEST_ROM_RD should be
asserted. The first read from the ROM does not occur until C4.
Clock 5 (C5)
On the fifth cycle, the next address should be driven and TEST_RD should be asserted. The
remaining addresses are driven each successive clock cycle and TEST_ROM_RD should
remain asserted until the last data value has been read from the ROM.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
Clock 6 (C6)
Cycle six is identical to C5. The MWDATA[31:0] signals are driven with the first data, five
cycles after the associated address was driven. TEST_RD should remain asserted until the
last data value has been driven onto MWDATA[31:0].
Clock n (Cn)
The remaining clock cycles in the test are identical to C6.
Throughout the entire sequence, the data value being driven is associated with the address
driven five clock cycles earlier. For this reason, five stall cycles (TEST_CTRL negated)
should occur after the last address is driven before the next sequence to wait for the last
data to be driven.
8.3.8 SRAM Testing
The SRAM consists of up to 8K longwords that can be accesses individually through the test
bus. Testing the compiled SRAM is accomplished by first writing test patterns into the
SRAM, reading the SRAM, and verifying the results.
8.3.8.1 SRAM WRITE FUNCTION. Writing to the SRAM is performed though the test bus
and MRDATA[31:0] after entering test mode. The address and control signals are input on
the test bus and the data to be written to the SRAM is input on MRDATA[31:0].
Writes to the SRAM are performed in a pipelined fashion as shown in Figure 8-11. All input
signals are latched on the positive edge of CLK and all outputs transition on the positive
edge of CLK.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
C1
A0
C2
C3
C4
C5
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
MRDATA
A1
D0
A2
D1
A3
D2
A0
A4
D3
A1
TEST_SRAM_WRT
SRAM_ADDR
SRAM_CSB
SRAM_RWB
SRAM_DI
D0
D1
SRAM_ST
Figure 8-11. Test SRAM Write Cycles
Clock 1 (C1)
On the first clock cycle of the SRAM write sequence, the first SRAM address should be
driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the first data value associated with the address asserted in C1 should
be driven onto MRDATA[31:0] and the next address should be driven onto
TEST_ADDR[14:2].
Clock 3 (C3)
On the third cycle, the next address and data values should be driven and
TEST_SRAM_WRT should be asserted. The remaining addresses and data are driven each
successive clock cycle and TEST_SRAM_WRT should remain asserted until the last data
value has been latched.
Clock 4 (C4)
On the fourth cycle, the next address and data values should be driven. The first write to the
SRAMs occurs in cycle four, three cycles after the first address was driven.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
Clock n (Cn)
The remaining clock cycles in the test are identical to C4.
Throughout the entire sequence, the data value being driven is associated with the address
driven in the previous clock cycle.
8.3.8.2 SRAM READ FUNCTION. Reading from the SRAM is performed though the test
bus and the MWDATA[31:0] after entering test mode. The address and control signals are
input on the test bus and the data from the SRAM is output on MWDATA[31:0].
Reads from the SRAM are performed in a pipelined fashion as shown in Figure 8-12. All
input signals are latched on the positive edge of CLK and all outputs transition on the
positive edge of CLK.
C1
A0
C2
A1
C3
A2
C4
A3
C5
A4
C6
A5
CN
A6
CLK
TEST_MODE
TEST_ADDR
TEST_CTRL
TEST_SRAM_RD
TEST_RD
SRAM_ADDR
SRAM_CSB
SRAM_RWB
SRAM_ST
A0
A1
A2
A3
SRAM_DO
D0
D1
D2
D0
D3
D1
MWDATA
Figure 8-12. Test SRAM Read Cycles
Clock 1 (C1)
On the first clock cycle of the SRAM read sequence, the first SRAM address should be
driven onto TEST_ADDR[14:2] and TEST_CTRL should be asserted.
Clock 2 (C2)
On the second cycle, the next addresses should be driven onto TEST_ADDR[14:2].
8-26
ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
Clock 3 (C3)
The third cycle is identical to C2.
Clock 4 (C4)
On the fourth cycle, the next address should be driven and TEST_SRAM_RD should be
asserted. The first read to the SRAM does not occur until C4, three cycles after the first
address was driven.
Clock 5 (C5)
On the fifth cycle, the next address should be driven and TEST_RD should be asserted. The
remaining addresses are driven each successive clock cycle and TEST_SRAM_RD should
remain asserted until the last data value has been read from the SRAM.
Clock 6 (C6)
Cycle six is identical to C5. The MWDATA[31:0] signals are driven with the first data, five
cycles after the associated address was driven. TEST_RD should remain asserted until the
last data value has been driven onto MWDATA[31:0].
Clock n (Cn)
The remaining clock cycles in the test are identical to C6.
Throughout the entire sequence, the data value being driven is associated with the address
driven five clock cycles earlier. For this reason, five stall cycles (TEST_CTRL negated)
should occur after the last address is driven before the next sequence to wait for the last
data to be driven.
8.3.8.3 SRAM WRITE FOLLOWED BY READ FUNCTION. The following timing diagram
illustrates the minimum number of cycles necessary to perform a write followed by read of
the SRAM. A certain sequence is neccessary because of the pipelined datapath to the
arrays from MRDATA and MWDATA.
8-27
ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
A0 A1
A2
TEST_ADDR
A3
TEST_CTRL
TEST_KTA
TEST_IDATA_RD
TEST_RD
D0
D1
D1
A2
D1
D2
TEST_RHIT
D3
D0 D1
D2
A3
MWDATA
ICH_ADDR[14:2]
A0
D0
A1
ICHD_DO
D2 D3
D1
If 8K cache, TEST_ADDR[14:13] are used as the lower two bits of data to be compared for the hit signal.
Figure 8-13. SRAM Write Followed by Read
Clock 1 (C1)
On the first clock cycle , A1, SRAM address, should be driven onto TEST_ADDR[14:2] and
TEST_SRAM_WRT should be asserted.
Clock 2 (C2)
On the second cycle, D1 (the data value associated with A1, the address asserted in C1)
should be driven onto MRDATA[31:0]. A1 must continue to be driven during this cycle.
TEST_SRAM_WRT remains asserted.
Clock 3 (C3)
C3 is a stall cycle. TEST_SRAM_WRT must remain asserted
Clock 4 (C4)
C4 is a stall cycle. TEST_SRAM_WRT must negate during this cycle which does the actual
WRITE of A1/D1 at the array. TEST_SRAM_RD must assert during this cycle.
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ColdFire2/2M User’s Manual
MOTOROLA
Test Operation
Clock 5 (C5)
The next SRAM address, A2, should be driven onto TEST_ADDR[14:2] during this cycle.
TEST_RD is asserted here; it will remain asserted during the next cycle C5, and then repeat
2 cycles negated, 2 cycles asserted for the duration of this type of test. TEST_IDATA_WRT
remains negated during this cycle; it will repeat two cycles asserted, two cyles negated.
TEST_SRAM_RD remains asserted during this cycle. The acutal READ of the ICACHE data
array C1/C2 (A1/D1) access occurs during this cycle.
Clock 6 (C6)
D2, associated with A2, is driven onto MRDATA[31:0] during this cycle. A2 remains driven.
TEST_RD remains asserted, TEST_SRAM_RD negates, and TEST_SRAM_WRT asserts
during this cycle.
Clock 7 (C7)
D1 is driven onto MWDATA[31:0]. This is a stall cycle; TEST_SRAM_RD remains negated,
TEST_RD negates, and TEST_SRAM_WRT remains asserted during this cycle.
Clock 8 (C8)
The repetition of C4-C7 begins on C8. TEST_SRAM_RD is asserted, TEST_RD negated,
and TEST_SRAM_WRT negated during this cycle. The actual WRITE of A2/D2 at the array
occurs during this cycle.
Clock 9 (C9)
C9 mimmicks C5: TEST_SRAM_RD remains asserted, TEST_RD asserts, and
TEST_SRAM_WRT remains negated. A3 is driven onto TEST_ADDR[14:2]. The actual
READ of A2/D2 at the array occurs during this cycle.
Clock 10 (C10)
C10 mimmicks C6: A3 remains driven on TEST_ADDR[14:2]; D3 asserts on
MRDATA[31:0]. TEST_SRAM_RD negates, TEST_RD remains asserted, and
TEST_SRAM_WRT asserts during this cycle.
Clock 11 (C11)
C11 mimmicks C7: D2 is driven onto MWDATA[31:0]. This is a stall cycle; TEST_SRAM_RD
remains negated, TEST_RD negates, and TEST_SRAM_WRT remains asserted during this
cycle.
This periodic 4-cycle sequence continues; ie. C4-C7 are repeated during C8-C11, C12-C15,
etc. The “C4” cycle is the actual WRITE cyle and the “C5” cycle is the actual READ cycle.
During the “C7’ cycle the data from the previous actual WRITE/READ sequence at the array
is displayed on MWDATA.
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ColdFire2/2M User’s Manual
MOTOROLA
SECTION 9
INSTRUCTION EXECUTION TIMING
This section presents ColdFire2/2M instruction execution times in terms of clock cycles. The
number of operand references for each instruction is also included, enclosed in parentheses
following the number of clock cycles. Each timing entry is presented as C(r/w) where:
• C - The number of ColdFire2/2M clock cycles, including all applicable operand fetches
and writes, as well as all internal cycles required to complete the instruction execution.
• r/w - The number of operand reads (r) and writes (w) required by the instruction. An
operation performing a read-modify-write function is denoted as (1/1).
This section includes assumptions concerning the timing values and the execution time
details and applies to both the ColdFire2 and ColdFire2M unless otherwise noted.
9.1 TIMING ASSUMPTIONS
The timing data presented in this section have the following assumptions:
1. The operand execution pipeline (OEP) is loaded with the opword and all required
extension words at the beginning of each instruction execution. This implies that the
OEP doesn’t wait for the instruction fetch pipeline (IFP) to supply opwords and/or
extension words.
2. The OEP does not experience any sequence-related pipeline stalls. For the ColdFire2/
2M, the most common example of this type of stall involves consecutive STORE
operations, excluding the MOVEM instruction. For all STORE operations (except
MOVEM), certain hardware resources within the ColdFire2/2M are marked as ‘busy’
for two clock cycles after the final DSOC cycle of the STORE instruction. If a
subsequent STORE instruction is encountered within this 2-cycle window, it will be
stalled until the resource again becomes available. Thus, the maximum pipeline stall
involving consecutive STORE operations is 2 cycles. The MOVEM instruction uses a
different set of resources and this stall does not apply.
3. The OEP completes all memory accesses without any stall conditions caused by the
memory itself. Thus, the timing details provided in this section assume an infinite zero-
wait state memory is attached to the ColdFire2/2M.
4. All operand data accesses are aligned on the same byte boundary as the operand
size: 16-bit operands aligned on 0-modulo-2 addresses, 32-bit operands aligned on 0-
modulo-4 addresses.
MOTOROLA
ColdFire2/2M User’s Manual
9-1
Instruction Execution Timing
If the operand alignment fails these guidelines, the misalignment unit is used. The processor
core decomposes the misaligned operand reference into a series of aligned accesses as
shown in Table 9-1.
Table 9-1. Misaligned Operand References
ADDRESS[1:0]
SIZE
KBUS OPERATIONS
ADDITIONAL C(R/W)
x1
word
byte, byte
2(1/0) if read
1(0/1) if write
x1
10
long
long
byte, word, byte
word, word
3(2/0) if read
2(0/2) if write
2(1/0) if read
1(0/1) if write
9.2 MOVE INSTRUCTION EXECUTION TIMES
The execution times for the MOVE.{B,W} instructions are shown in Table 9-2, while Table
9-3 provides the timing for MOVE.L.
For all tables in this section, the execution time (ET) of any instruction using the PC-relative
effective addressing modes is exactly equivalent to the time using the comparable An-
relative mode.
The nomenclature “xxx.wl” refers to both forms of absolute addressing, xxx.w and xxx.l.
9-2
ColdFire2/2M User’s Manual
MOTOROLA
Instruction Execution Timing
.
Table 9-2. Move Byte and Word Execution Times
DESTINATION
SOURCE
RX
(AX)
(AX)+
1(0/1)
1(0/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(0/1)
-(AX)
1(0/1)
1(0/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(0/1)
(D16,AX)
1(0/1)
1(0/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
—
(D8,AX,XN*SF)
XXX.WL
1(0/1)
1(0/1)
3(1/1)
3(1/1)
3(1/1)
—
Dy
Ay
1(0/0)
1(0/0)
3(1/0)
3(1/0)
3(1/0)
3(1/0)
4(1/0)
3(1/0)
3(1/0)
3(1/0)
4(1/0)
1(0/0)
1(0/1)
1(0/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(0/1)
2(0/1)
2(0/1)
4(1/1)
4(1/1)
4(1/1)
—
(Ay)
(Ay)+
-(Ay)
(d16,Ay)
(d8,Ay,Xn*SF)
xxx.w
—
—
—
—
—
xxx.l
—
—
—
(d16,PC)
(d8,PC,Xn*SF)
#xxx
3(1/1)
—
—
—
—
—
—
—
—
Table 9-3. Move Long Execution Times
DESTINATION
SOURCE
RX
(AX)
(AX)+
1(0/1)
1(0/1)
2(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(0/1)
-(AX)
1(0/1)
1(0/1)
2(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(0/1)
(D16,AX)
1(0/1)
1(0/1)
2(1/1)
2(1/1)
2(1/1)
2(1/1)
—
(D8,AX,XN*SF)
XXX.WL
1(0/1)
1(0/1)
2(1/1)
2(1/1)
2(1/1)
—
Dy
Ay
1(0/0)
1(0/0)
2(1/0)
2(1/0)
2(1/0)
2(1/0)
3(1/0)
2(1/0)
2(1/0)
2(1/0)
3(1/0)
1(0/0)
1(0/1)
1(0/1)
2(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(1/1)
2(1/1)
2(1/1)
3(1/1)
2(0/1)
2(0/1)
2(0/1)
3(1/1)
3(1/1)
3(1/1)
—
(Ay)
(Ay)+
-(Ay)
(d16,Ay)
(d8,Ay,Xn*SF)
xxx.w
—
—
—
—
—
xxx.l
—
—
—
(d16,PC)
(d8,PC,Xn*SF)
#xxx
2(1/1)
—
—
—
—
—
—
—
—
MOTOROLA
COLDFIRE2/2M User’s Manual
9-3
Instruction Execution Timing
9.3 STANDARD ONE OPERAND INSTRUCTION EXECUTION TIMES
Table 9-4. One Operand Instruction Execution Times
EFFECTIVE ADDRESS
OPCODE <EA>
RN
(AN)
1(0/1)
1(0/1)
1(0/1)
—
(AN)+
1(0/1)
1(0/1)
1(0/1)
—
-(AN)
1(0/1)
1(0/1)
1(0/1)
—
(D16,AN) (D8,AN,XN*SF) XXX.WL
#XXX
—
clr.b
clr.w
clr.l
<ea>
<ea>
<ea>
Dx
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/1)
1(0/1)
1(0/1)
—
2(0/1)
2(0/1)
2(0/1)
—
1(0/1)
1(0/1)
1(0/1)
—
—
—
ext.w
ext.l
—
Dx
—
—
—
—
—
—
—
extb.l
neg.l
negx.l
not.l
Dx
—
—
—
—
—
—
—
Dx
—
—
—
—
—
—
—
Dx
—
—
—
—
—
—
—
Dx
—
—
—
—
—
—
—
scc
Dx
—
—
—
—
—
—
—
swap
tst.b
Dx
—
—
—
—
—
—
—
<ea>
<ea>
<ea>
3(1/0)
3(1/0)
2(1/0)
3(1/0)
3(1/0)
2(1/0)
3(1/0)
3(1/0)
2(1/0)
3(1/0)
3(1/0)
2(1/0)
4(1/0)
4(1/0)
3(1/0)
3(1/0)
3(1/0)
2(1/0)
1(0/0)
1(0/0)
1(0/0)
tst.w
tst.l
9-4
ColdFire2/2M User’s Manual
MOTOROLA
Instruction Execution Timing
9.4 STANDARD TWO OPERAND INSTRUCTION EXECUTION TIMES
Table 9-5. Two Operand Instruction Execution Times
EFFECTIVE ADDRESS
OPCODE
<EA>
(D16,AN) (D8,AN,XN*SF)
(D16,PC) (D8,PC,XN*SF)
RN
(AN)
(AN)+
-(AN)
XXX.WL #XXX
add.l
add.l
addi.l
addq.l
addx.l
and.l
and.l
andi.l
asl.l
<ea>,Rx
Dy,<ea>
#imm,Dx
#imm,<ea>
Dy,Dx
1(0/0)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
4(1/0)
4(1/1)
—
3(1/0)
3(1/1)
—
1(0/0)
—
1(0/0)
1(0/0)
1(0/0)
1(0/0)
—
—
3(1/1)
—
3(1/1)
—
3(1/1)
—
3(1/1)
—
4(1/1)
—
3(1/1)
—
—
—
<ea>,Dn
Dy,<ea>
#imm,Dx
<ea>,Dx
<ea>,Dx
Dy,<ea>
#imm,<ea>
Dy,<ea>
#imm,<ea>
Dy,<ea>
#imm,<ea>
Dy,<ea>
#imm,<ea>
<ea>,Rx
#imm,Dx
Dy,<ea>
#imm,Dx
<ea>,Ax
<ea>,Dx
<ea>,Dx
#imm,Dx
<ea>,Dx
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
4(1/0)
4(1/1)
—
3(1/0)
3(1/1)
—
1(0/0)
—
1(0/0)
1(0/0)
1(0/0)
2(0/0)
2(0/0)
2(0/0)
2(0/0)
2(0/0)
2(0/0)
2(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
1(0/0)
—
—
—
—
—
—
—
—
1(0/0)
1(0/0)
—
asr.l
—
—
—
—
—
—
bchg
bchg
bclr
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/0)
—
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/0)
—
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/0)
—
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
3(1/0)
—
4(1/1)
—
3(1/1)
—
—
4(1/1)
—
3(1/1)
—
—
bclr
—
bset
bset
btst
4(1/1)
—
3(1/1)
—
—
—
4(1/1)
—
3(1/1)
—
—
btst
1(0/0)
1(0/0)
—
cmp.l
cmpi.l
eor.l
4(1/0)
—
3(1/0)
—
3(1/1)
—
3(1/1)
—
3(1/1)
—
3(1/1)
—
4(1/1)
—
3(1/1)
—
—
eori.l
lea
—
1(0/0)
—
—
—
1(0/0)
—
2(0/0)
—
1(0/0)
—
—
lsl.l
1(0/0)
1(0/0)
—
—
—
1(0/0)
1(0/0)
1(0/0)
lsr.l
—
—
—
—
—
—
moveq
muls.w
—
—
—
—
—
—
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
2
9(0/0)
3(0/0)
9(0/0)
3(0/0)
11(1/0)
11(1/0)
11(1/0)
11(1/0)
12(1/0)
11(1/0) 9(0/0)
2
1
2
2
2
2
2
2
2
5(1/0)
5(1/0)
5(1/0)
5(1/0)
6(1/0)
5(1/0)
3(0/0)
1
mulu.w
muls.l
mulu.l
<ea>,Dx
<ea>,Dx
<ea>,Dx
11(1/0)
11(1/0)
11(1/0)
11(1/0)
12(1/0)
11(1/0) 9(0/0)
2
2
2
2
2
2
5(1/0)
5(1/0)
5(1/0)
5(1/0)
6(1/0)
-
5(1/0)
-
3(0/0)
-
1
18(0/0)
20(1/0)
20(1/0)
20(1/0)
20(1/0)
2
2
2
2
2
-
-
-
-
-
-
-
-
-
5(0/0)
7(1/0)
7(1/0)
7(1/0)
7(1/0)
1
18(0/0)
20(1/0)
20(1/0)
20(1/0)
20(1/0)
2
2
2
2
2
5(0/0)
1(0/0)
—
7(1/0)
3(1/0)
3(1/1)
—
7(1/0)
3(1/0)
3(1/1)
—
7(1/0)
3(1/0)
3(1/1)
—
7(1/0)
3(1/0)
3(1/1)
—
or.l
or.l
<ea>,Dn
Dy,<ea>
#imm,Dx
<ea>,Rx
Dy,<ea>
#imm,Dx
4(1/0)
4(1/1)
—
3(1/0)
3(1/1)
—
1(0/0)
—
or.l
1(0/0)
1(0/0)
—
—
sub.l
sub.l
subi.l
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
3(1/0)
3(1/1)
—
4(1/0)
4(1/1)
—
3(1/0)
3(1/1)
—
1(0/0)
—
1(0/0)
—
NOTES: 1. Applies to the ColdFire2 only.
2. Applies to the ColdFire2M only.
MOTOROLA
COLDFIRE2/2M User’s Manual
9-5
Instruction Execution Timing
Table 9-5. Two Operand Instruction Execution Times (Continued)
EFFECTIVE ADDRESS
OPCODE
<EA>
(D16,AN) (D8,AN,XN*SF)
RN
(AN)
(AN)+
-(AN)
XXX.WL #XXX
(D16,PC) (D8,PC,XN*SF)
subq.l
subx.l
#imm,<ea>
Dy,Dx
1(0/0)
1(0/0)
3(1/1)
—
3(1/1)
—
3(1/1)
—
3(1/1)
—
4(1/1)
—
3(1/1)
—
—
—
NOTES: 1. Applies to the ColdFire2 only.
2. Applies to the ColdFire2M only.
9-6
ColdFire2/2M User’s Manual
MOTOROLA
Instruction Execution Timing
9.5 MISCELLANEOUS INSTRUCTION EXECUTION TIMES
Table 9-6. Miscellaneous Instruction Execution Times
EFFECTIVE ADDRESS
OPCODE
<EA>
RN
(AN)
9(0/1)
—
(AN)+
—
-(AN)
—
(D16,AN) (D8,AN,XN*SF) XXX.WL #XXX
cpush
link.w
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Ay,#imm
CCR,Dx
<ea>,CCR
SR,Dx
2(0/1)
1(0/0)
1(0/0)
1(0/0)
7(0/0)
—
—
move.w
move.w
move.w
move.w
—
—
—
—
—
—
—
1(0/0)
—
—
—
—
2
<ea>,SR
—
—
—
7(0/0)
1(0/0)
1
<ea>,ACC
<ea>,MACSR
<ea>,MASK
ACC,<ea>
1(0/0)
1(0/0)
1(0/0)
2(0/0)
2(0/0)
2(0/0)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
move.l
1
-
-
1(0/0)
move.l
1
-
-
1(0/0)
move.l
1
-
-
-
-
-
move.l
1
MACSR,<ea>
MASK,<ea>
-
-
move.l
1
-
—
-
—
move.l
movec
Ry,Rc
9(0/1)
—
—
—
—
—
—
—
—
—
—
—
3
3
3
3
movem.l
<ea>,&list
1+n(n/0)
1+n(n/0)
movem.l
&list,<ea>
—
—
—
—
—
—
—
1+n(0/n)
—
1+n(0/n)
—
nop
pea
—
3(0/0)
—
—
—
—
—
—
—
—
4
5
<ea>
2(0/1)
2(0/1)
2(0/1)
3(0/1)
—
pulse
stop
1(0/0)
—
—
—
—
—
—
—
—
—
—
—
—
6
#imm
#imm
—
3(0/0)
trap
tpf
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
15(1/2)
—
1(0/0)
1(0/0)
1(0/0)
2(1/0)
—
tpf.w
#imm
#imm
Ax
—
—
—
—
—
—
tpf.l
—
—
—
—
—
—
unlk
—
—
—
—
—
—
wddata
wdebug
<ea>
<ea>
3(1/0)
5(2/0)
3(1/0)
—
3(1/0)
—
3(1/0)
5(2/0)
4(1/0)
—
3(1/0)
—
3(1/0)
—
—
NOTES: 1. Applies to the ColdFire2M only.
2. If a MOVE.W #imm,SR instruction is executed and imm[13] = 1, the execution time is 1(0/0).
3. n is the number of registers moved by the movem opcode.
4. PEA execution times are the same for (d16,PC)
5. PEA execution times are the same for (d8,PC,Xn*SF)
6. The execution time for STOP is the time required until the ColdFire2/2M begins sampling continuously for
interrupts.
MOTOROLA
COLDFIRE2/2M User’s Manual
9-7
Instruction Execution Timing
9.6 MAC INSTRUCTION EXECUTION TIMING
These instructions are supported on the ColdFire2M only.
Table 9-7. MAC Instruction Execution Times
EFFECTIVE ADDRESS
OPCODE
<EA>
(D16,AN) (D8,AN,XN*SF)
(D16,PC) (D8,PC,XN*SF)
RN
(AN)
(AN)+
-(AN)
XXX.WL #XXX
mac.w
mac.l
Ry,Rx
Ry,Rx
1(0/0)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3(0/0)
-
-
-
-
msac.w
msac.l
macl.w
macl.l
Ry,Rx
1(0/0)
-
-
-
-
Ry,Rx
3(0/0)
-
-
-
-
Ry,Rx,<ea>,Rw
Ry,Rx,<ea>,Rw
-
-
-
-
2(1/0)
4(1/0)
2(1/0)
4(1/0)
2(1/0)
4(1/0)
2(1/0)
4(1/0)
2(1/0)
4(1/0)
2(1/0)
4(1/0)
2(1/0)†
4(1/0)†
2(1/0)†
4(1/0)†
msacl.w Ry,Rx,<ea>,Rw
msacl.l Ry,Rx,<ea>,Rw
NOTE: †Effective address of (d16,PC) not supported
9.7 BRANCH INSTRUCTION EXECUTION TIMES
Table 9-8. General Branch Instruction Execution Times
EFFECTIVE ADDRESS
OPCODE <EA>
RN
—
—
—
—
—
(AN)
—
(AN)+
—
-(AN)
—
(D16,AN) (D8,AN,XI*SF) XXX.WL
#XXX
—
bsr
3(0/1)
3(0/0)
3(0/1)
—
—
4(0/0)
4(0/1)
—
—
3(0/0)
3(0/1)
—
jmp
jsr
<ea>
<ea>
3(0/0)
3(0/1)
—
—
—
—
—
—
—
rte
rts
8(2/0)
5(1/0)
—
—
—
—
—
—
—
—
Table 9-9. BRA, Bcc Instruction Execution Times
FORWARD
TAKEN
2(0/0)
FORWARD
NOT TAKEN
—
BACKWARD
TAKEN
2(0/0)
BACKWARD
OPCODE
NOT TAKEN
—
bra
Bcc
3(0/0)
1(0/0)
2(0/0)
3(0/0)
9-8
ColdFire2/2M User’s Manual
MOTOROLA
APPENDIX A
REGISTER SUMMARY
A.1 REGISTER ACCESS METHODS
All of the ColdFire2/2M registers are accessed via special instructions or addressing modes.
None of them are mapped into the user data address space. Table A-1 lists the
ColdFire2/2M registers and their control register addresses.
Table A-1. Register Summary
1
2
PROGRAM ACCESS
DEBUG ACCESS
REGISTER
ACRONYM
INSTRUCTION
WDEBUG
RC
COMMAND
WDMREG
DRC
Address Attribute Register
AATR
ABHR
ABLR
ACR0
ACR1
ACC
$6
$C
$D
$6
$C
Address Breakpoint Registers (High)
Address Breakpoint Registers (Low)
Access Control Register 0
WDEBUG
WDMREG
WDEBUG
WDMREG
$D
MOVEC
MOVEC
$004
$005
-
RCREG,WCREG
RCREG,WCREG
RCREG,WCREG
$004
$005
$806
Access Control Register 1
3
MOVE to/from ACC
Accumulator
Address Registers
A0-A6
CACR
CCR
MOVE
MOVEC
-
$002
-
RAREG,WAREG
RCREG,WCREG
-
Cache Control Register
Condition Code Register
Configuration/Status Register
Data Breakpoint Mask Register
Data Breakpoint Register
Data Registers
$002
MOVE to/from CCR
WDEBUG
RCREG,WCREG $80E
CSR
$0 RDMREG,WDMREG $0
DBMR
DBR
WDEBUG
$F
$E
-
WDMREG
WDMREG
$F
$E
WDEBUG
D0-D7
MOVE
RDREG,WDREG
RCREG,WCREG
-
3
MACSR MOVE to/from MACSR
-
$804
MAC Status Register
3
MASK
MOVE to/from MASK
-
RCREG,WCREG
$805
Mask Register
Program Counter
PC
-
-
RCREG,WCREG $80F
Program Counter Breakpoint Mask Register
Program Counter Breakpoint Register
RAM Base Address Register
ROM Base Address Register
PBMR
WDEBUG
WDEBUG
MOVEC
MOVEC
$9
$8
WDMREG
WDMREG
$9
$8
PBR
RAMBAR0
ROMBAR0
$C04 RCREG,WCREG $C04
$C00 RCREG,WCREG $C00
NOTES: 1. Refer to the ColdFireProgrammer’sReferenceManual (MCF5200PRM/AD).
2. Refer to Section 7.3.3.1 BDM Command Set Summary.
3. ColdFire2M only.
MOTOROLA
ColdFire2/2M User’s Manual
A-1
Register Summary
Table A-1. Register Summary (Continued)
1
2
PROGRAM ACCESS
DEBUG ACCESS
REGISTER
ACRONYM
INSTRUCTION
MOVE
RC
COMMAND
DRC
Stack Pointer
A7,SP
SR
-
-
RAREG/WAREG
-
Status Register
MOVE to/from SR
WDEBUG
RCREG,WCREG $80E
Trigger Definition Register
Vector Base Register
TDR
VBR
$7
WDMREG
$7
MOVEC
$801
RCREG,WCREG
$801
NOTES: 1. Refer to the ColdFireProgrammer’sReferenceManual (MCF5200PRM/AD).
2. Refer to Section 7.3.3.1 BDM Command Set Summary.
3. ColdFire2M only.
A.1 REGISTER FORMATS
BITS
FIELD
RESET
R/W
15
RM
0
14
13
12
11
10
8
7
R
0
6
5
4
3
2
0
SZM
TTM
TMM
0
SZ
0
TT
0
TM
101
W
0
0
W
W
W
W
W
W
W
Figure A-2. Address Attribute Register (AATR)
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Figure A-3. Address Breakpoint High Register (ABHR)
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Figure A-4. Address Breakpoint Low Register (ABLR)
A-2
ColdFire2/2M User’s Manual
MOTOROLA
Register Summary
16
BITS
31
24
23
FIELD
AB
0
AM
0
RESE
T
R/W
W
W
BITS
15
14
13
12
8
7
6
5
4
3
2
1
0
BUF
W
FIELD EN
SM
-
ENIB CM
-
WP
-
RESE
T
0
0
-
-
0
0
0
-
-
0
-
-
R/W
W
W
W
W
W
W
Figure A-5. Access Control Register (ACR0, ACR1)
BITS
31
30
29
28
27
26
25
24
23
18
17
16
CEN
B
CPS CFR
FIELD
-
-
CINV
-
PARK
H
0
Z
0
RESE
T
0
-
-
-
-
0
-
-
0
R/W
W
W
W
W
W
BITS
15
11
10
9
8
7
6
5
4
2
1
0
CBE CMO CBU
CWR
P
FIELD
-
-
-
CLNF
N
D
F
RESE
T
-
-
0
0
0
-
-
0
-
-
0
R/W
W
W
W
W
W
Figure A-6. Cache Control Register (CACR)
BITS
7
-
6
-
5
-
4
X
3
N
2
Z
1
V
0
0
C
FIELD
RESET
R/W
0
R
0
R
0
R
0
0
0
0
R/W
R/W
R/W
R/W
R/W
Figure A-7. Condition Code Register (CCR)
MOTOROLA
ColdFire2/2M User’s Manual
A-3
Register Summary
BITS
31
28
27
26
25
24
23
17
16
HAL BKP
FIELD
STATUS
FOF TRG
-
IPW
T
0
T
0
RESE
T
0
0
0
-
-
0
1
R/W
R
R
R
R
R
R/W
BITS
15
14
13
12
11
10
9
8
7
6
5
4
3
0
FIELD MAP TRC EMU
DDC
UHE
BTB
0
-
NPL
IPI SSM
-
-
-
RESE
T
0
0
0
0
0
0
0
0
0
R/W† R/W R/W R/W
R/W
R/W
R/W
R
R/W R/W R/W
NOTE: †The CSR is a write only register from the programming model. It can be read from and written to via the BDM
port.
Figure A-8. Configuration/Status Register (CSR)
BITS
FIELD
RESET
R/W
31
0
MASK
-
W
Figure 1-9. Data Breakpoint Mask Register (DBMR)
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Figure 1-10. Data Breakpoint Register (DBR)
BITS
FIELD
RESET
R/W
7
OMC
0
6
S/U
0
5
-
4
-
3
N
2
Z
1
V
0
C
0
0
R
0
R
-
-
-
R/W
R/W
R/W
R/W
R/W
R
Figure 1-11. MAC Status Register (MACSR)
A-4
ColdFire2/2M User’s Manual
MOTOROLA
Register Summary
0
BITS
15
FIELD
MASK
-
RESE
T
R/W
R/W
Figure 1-12. MAC Mask Register (MASK)
BITS
FIELD
RESET
R/W
31
0
MASK
-
W
Figure 1-13. Program Counter Breakpoint Mask Register (PBMR)
BITS
FIELD
RESET
R/W
31
0
ADDRESS
-
W
Figure 1-14. Program Counter Breakpoint Register (PBR)
BITS
31
16
FIELD
BA
-
RESE
T
R/W
W
BITS
15
9
8
7
6
5
4
3
2
1
0
FIELD
BA
-
WP
-
-
-
CSM SCM SDM UCM UDM
V
RESE
T
-
-
-
-
-
-
0
R/W
W
W
W
W
W
W
W
W
Figure A-15. SRAM Base Address Register (RAMBAR0)
MOTOROLA
ColdFire2/2M User’s Manual
A-5
Register Summary
BITS
31
16
FIELD
BA
- (0)
W
RESE
T
R/W
BITS
15
9
8
7
6
5
4
3
2
1
0
FIELD
BA
- (0)
W
WP
- (1)
W
-
-
-
CSM SCM SDM UCM UDM
V
RESE
T
- (1) - (0) - (0) - (0) - (0) 0 (1)
R/W
W
W
W
W
W
W
NOTE: The reset values in parenthesis are valid if the ROM_VLD signal is asserted during reset.
Figure A-16. ROM Base Address Register (ROMBAR0)
BITS
FIELD
RESET
R/W
15
T
14
-
13
S
12
M
1
11
-
10
8
7
5
4
X
0
3
N
0
2
Z
0
1
V
0
0
C
0
I
7
-
0
0
1
0
0
R
R/W
R
R/W R/W
R
R/W
R/W R/W R/W R/W R/W
Figure A-17. Status Register (SR)
BITS
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
EDL EDW EDW EDL EDL EDU EDU
FIELD
TRC
EBL
DI
EAI EAR EAL EPC PCI
W
0
L
0
U
0
L
0
M
0
M
0
U
0
RESE
T
0
0
0
0
0
0
0
0
R/W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
BITS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EDL EDW EDW EDL EDL EDU EDU
FIELD
-
EBL
DI
EAI EAR EAL EPC PCI
W
L
U
L
M
M
U
RESE
T
-
-
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R/W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
Figure A-18. Trigger Definition Register (TDR)
A-6
ColdFire2/2M User’s Manual
MOTOROLA
APPENDIX B
NEW MAC INSTRUCTIONS
B.1 ENHANCED INTEGER-MULTIPLY INSTRUCTIONS
Opcodes for the MULS and MULU instructions are described in the MCF5200 Family
Programmer’s Reference Manual. The only change to these opcodes is the improved
execution efficiency.
B.2 NEW MAC INSTRUCTIONS
This section describes the new MAC instructions for the ColdFire2M. Details of each
instruction description are arranged in alphabetical order by instruction mnemonic. For
notational conventions, refer to Table 1-4 in Section 1.8 Instruction Set Summary.
MOTOROLA
ColdFire2/2M User’s Manual
B-1
New MAC Instructions
MAC
Operation:
Multiply and Accumulate
MAC
ACC + ((Ry × Rx){<< 1 | >> 1}) → ACC
Assembler
Syntax:
MAC.<size> Ry.<ul>,Rx.<ul>
MAC.<size> Ry.<ul>,Rx.<ul>,<shift>
Attributes:
size = (Word, Long)
ul = (Upper, Lower)
shift = (<<, >>)
Description: Multiplies two 16- or 32-bit numbers to produce a 32-bit result, then adds this
product, optionally shifted left or right one bit, to the accumulator (ACC). The result is
stored back into the accumulator. If 16-bit operands are used, the upper or lower word
of each register must be specified.
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
*
C
0
-
-
0
0
OMC - not affected.
S/U
N
Z
V
C
-
-
-
-
-
not affected.
set if the most significant bit of the result is set, otherwise cleared.
set if the result is zero, otherwise cleared.
set if an overflow is generated, otherwise unchanged.
always cleared.
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
SZ
10
9
8
0
0
7
0
6
5
0
4
0
3
2
1
0
RW
RW
U/LX
RX
-
SF
U/LW
-
Instruction Fields:
Ry - Source Y field
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 6, 11, 10, 9 (MSB to LSB).
B-2
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
Rx - Source X field
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 3, 2, 1, 0 (MSB to LSB).
SZ - Size field
0 = word-sized input operands
1 = long-sized input operands
SF - Scale Factor field
00 = none
01 = product << 1
10 = reserved
11 = product >> 1
U/Ly -Source YWord Select field
This bit determines which 16-bit operand of the source W register is used in the operation
for word-sized operations only.
0 = lower word
1 = upper word
U/Lx - Source X Word Select field
This bit determines which 16-bit operand of the source X register is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
MOTOROLA
ColdFire2/2M User’s Manual
B-3
New MAC Instructions
MACL
Multiply and Accumulate
with Register Load
MACL
Operation:
ACC + ((Ry × Rx){<< 1 | >> 1}) → ACC
(<ea>{& MASK}) → Ry
Assembler
Syntax:
MACL.<size> Ry.<ul>,Rx.<ul>,<ea>,Rw
MACL.<size> Ry.<ul>,Rx.<ul>,<shift>,<ea>,Rw
MACL.<size> Ry.<ul>,Rx.<ul>,<shift>,<ea>&,Rw
Attributes:
size = (Word, Long)
ul = (Upper, Lower)
shift = (<<, >>)
ea = Effective Address
Description: Multiplies two 16- or 32-bit numbers to produce a 32-bit result, then adds this
product, optionally shifted left or right one bit, to the accumulator (ACC).The result is stored
back into the accumulator. If 16-bit operands are used, the upper or lower word of each
register must be specified. In parallel with this operation, a 32-bit operand is fetched from
the memory location defined by <ea> and loaded into the destination register, Rw. If the
mask addressing mode is used, the low-order word of <ea> is ANDed with the mask
register. Refer to Section 6.2.3 Mask Register (MASK).
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
*
C
0
-
-
0
0
OMC - not affected.
S/U
N
Z
V
C
-
-
-
-
-
not affected.
set if the most significant bit of the result is set, otherwise cleared.
set if the result is zero, otherwise cleared.
set if an overflow is generated, otherwise unchanged.
always cleared.
Processor Condition Codes:
Not affected
B-4
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
Instruction Format:
15
1
14
0
13
1
12
0
11
10
9
8
0
0
7
1
6
5
4
3
2
1
0
<EA>
RY
RY
MODE
0
REG
RW
SZ
SF
U/LY U/LX MAM
RX
Instruction Fields:
Ry -Source Yfield
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 15, 14, 13, 12 (MSB to LSB).
Rx - Source X field
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 3, 2, 1, 0 (MSB to LSB).
Rw - Destination field
Specifies a destination register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7.
Note that bit ordering is 6, 11, 10, 9 (MSB to LSB).
<ea> - Effective Address of Memory Operand field
ADDRESSING
MODE
ADDRESSING
MODE
MODE REGISTER
MODE REGISTER
Dn
An
-
-
-
-
(xxx).W
(xxx).L
-
-
-
-
-
-
(An)
010 reg.num:An
011 reg.num:An
100 reg.num:An
101 reg.num:An
#<data>
(An)+
-(An)
(d16,An)
(d8,An,Xn)
(d16,PC)
-
-
-
-
-
-
(d8,PC,Xn)
SZ - Size field
0 = word-sized input operands
1 = long-sized input operands
SF - Scale Factor field
00 = none
01 = product << 1
10 = reserved
11 = product >> 1
MOTOROLA
ColdFire2/2M User’s Manual
B-5
New MAC Instructions
U/Ly -Source YWord Select field
This bit determines which 16-bit operand of the source Yregister is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
U/Lx - Source X Word Select field
This bit determines which 16-bit operand of the source X register is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
MAM - Mask Addressing Mode Modifier
This bit determines if the mask addressing mode should be used. Refer to Section 6.2.3
Mask Register (MASK).
0 = normal addressing mode
1 = mask addressing mode
B-6
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
MSAC
Operation:
Multiply and Subtract
MSAC
ACC - ((Ry × Rx){<< 1 | >> 1}) → ACC
Assembler
Syntax:
MSAC.<size> Ry.<ul>,Rx.<ul>
MSAC.<size> Ry.<ul>,Rx.<ul>,<shift>
Attributes:
size = (Word, Long)
ul = (Upper, Lower)
shift = (<<, >>)
Description: Multiplies two 16- or 32-bit numbers to produce a 32-bit result, then
subtracts this product, optionally shifted left or right one bit, from the accumulator
(ACC). The result is stored back into the accumulator. If 16-bit operands are used, the
upper or lower word of each register must be specified.
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
*
C
0
-
-
0
0
OMC - not affected.
S/U
N
Z
V
C
-
-
-
-
-
not affected.
set if the most significant bit of the result is set, otherwise cleared.
set if the result is zero, otherwise cleared.
set if an overflow is generated, otherwise unchanged.
always cleared.
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
SZ
10
RY
9
8
0
1
7
0
6
5
0
4
0
3
2
1
0
RY
U/LX
RX
-
SF
U/LY
-
Instruction Fields:
Ry - Operand Yfield
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 6, 11, 10, 9 (MSB to LSB).
MOTOROLA
ColdFire2/2M User’s Manual
B-7
New MAC Instructions
Rx - Operand X field
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 3, 2, 1, 0 (MSB to LSB).
SZ - Size field
0 = word-sized input operands
1 = long-sized input operands
SF - Scale Factor field
00 = none
01 = product << 1
10 = reserved
11 = product >> 1
U/Ly -Source YWord Select field
This bit determines which 16-bit operand of the source Yregister is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
U/Lx - Source X Word Select field
This bit determines which 16-bit operand of the source X register is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
B-8
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
MSACL
Multiply and Subtract
with Register Load
MSACL
Operation:
ACC - ((Ry × Rx){<< 1 | >> 1}) → ACC
(<ea>{& MASK}) → Rw
Assembler
Syntax:
MSACL.<size> Ry.<ul>,Rx.<ul>,<ea>,Rw
MSACL.<size> Ry.<ul>,Rx.<ul>,<shift>,<ea>,Rw
MSACL.<size> Ry.<ul>,Rx.<ul>,<shift>,<ea>&,Rw
Attributes:
size = (Word, Long)
ul = (Upper, Lower)
shift = (<<, >>)
ea = Effective Address
Description: Multiplies two 16- or 32-bit numbers to produce a 32-bit result, then subtracts
this product, optionally shifted left or right one bit, from the accumulator (ACC).The result is
stored back into the accumulator. If 16-bit operands are used, the upper or lower word of
each register must be specified. In parallel with this operation, a 32-bit operand is fetched
from the memory location defined by <ea> and loaded into the destination register, Rw. If
the mask addressing mode is used, the low-order word of <ea> is ANDed with the mask
register. Refer to Section 6.2.3 Mask Register (MASK).
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
*
C
0
-
-
0
0
OMC - not affected.
S/U
N
Z
V
C
-
-
-
-
-
not affected.
set if the most significant bit of the result is set, otherwise cleared.
set if the result is zero, otherwise cleared.
set if an overflow is generated, otherwise unchanged.
always cleared.
Processor Condition Codes:
Not affected
MOTOROLA
ColdFire2/2M User’s Manual
B-9
New MAC Instructions
Instruction Format:
15
1
14
0
13
1
12
0
11
10
9
8
0
1
7
1
6
5
4
3
2
1
0
<EA>
RY
RY
MODE
0
REG
RW
SZ
SF
U/LY U/LX MAM
RX
Instruction Fields:
Ry -Source Yfield
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 15, 14, 13, 12 (MSB to LSB).
Rx - Source X field
Specifies a source register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7. Note
that bit ordering is 3, 2, 1, 0 (MSB to LSB).
Rw - Destination field
Specifies a destination register operand, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7.
Note that bit ordering is 6, 11, 10, 9 (MSB to LSB).
<ea> - Effective Address of Memory Operand field
ADDRESSING
MODE
ADDRESSING
MODE
MODE REGISTER
MODE REGISTER
Dn
An
-
-
-
-
(xxx).W
(xxx).L
-
-
-
-
-
-
(An)
010 reg.num:An
011 reg.num:An
100 reg.num:An
101 reg.num:An
#<data>
(An)+
-(An)
(d16,An)
(d8,An,Xn)
(d16,PC)
-
-
-
-
-
-
(d8,PC,Xn)
SZ - Size field
0 = word-sized input operands
1 = long-sized input operands
SF - Scale Factor field
00 = none
01 = product << 1
10 = reserved
11 = product >> 1
B-10
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
U/Ly -Source YWord Select field
This bit determines which 16-bit operand of the source Yregister is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
U/Lx - Source X Word Select field
This bit determines which 16-bit operand of the source X register is used in the operation for
word-sized operations only.
0 = lower word
1 = upper word
MAM - Mask Addressing Mode Modifier
This bit determines if the mask addressing mode should be used. Refer to Section 6.2.3
Mask Register (MASK).
0 = normal addressing mode
1 = mask addressing mode
B.3 NEW REGISTER INSTRUCTIONS
This section describes the new register instructions for the ColdFire2M. Details of each
instruction description are arranged in alphabetical order by instruction mnemonic. For
notational conventions, refer to Table 1-4 in Section 1.8 Instruction Set Summary.
MOTOROLA
ColdFire2/2M User’s Manual
B-11
New MAC Instructions
MOVE
MOVE
from ACC
from ACC
Move from Accumulator
Operation:
ACC → Rx
Assembler
Syntax:
MOVE.<size> ACC, Rx
size = Long
Attributes:
Description: Moves a 32-bit value from the accumulator (ACC) to a register.The size of the
operation must be specified as long.
MAC Status Register:
Not affected
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
0
10
0
9
0
8
1
7
1
6
0
5
0
4
0
3
0
RX
Instruction Fields:
Rx[3:0] specifies the destination register, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7.
B-12
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
MOVE
MOVE
from MACSR
from MACSR Move from MAC Status Reg
Operation:
MACSR → Rx[7:0]
0 → Rx[31:8]
Assembler
Syntax:
MOVE.<size> MACSR, Rx
size = Long
Attributes:
Description: Moves the contents of the MAC status register (MACSR), zero-extended to
long size, into a general-purpose register, Rx. The size of the operation must be
specified as long.
MAC Status Register:
Not affected
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
1
10
0
9
0
8
1
7
1
6
0
5
0
4
0
3
0
RX
Instruction Fields:
Rx[3:0] specifies the destination register, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7.
MOTOROLA
ColdFire2/2M User’s Manual
B-13
New MAC Instructions
MOVE
MOVE
from MASK
from MASK
Move from Mask
Operation:
MASK → Rx[15:0]
0xFFFF → Rx[31:16]
Assembler
Syntax:
MOVE.<size> MASK, Rx
size = Long
Attributes:
Description: Moves a 32-bit value from the mask register (MASK), one-extended to long
size, to a register. The size of the operation must be specified as long.
MAC Status Register:
Not affected
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
1
10
1
9
0
8
1
7
1
6
0
5
0
4
0
3
0
RX
Instruction Fields:
Rx[3:0] specifies the destination register, where $0 is D0,..., $7 is D7, $8 is A0,..., $F is A7.
B-14
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
MOVE
MOVE
to ACC
to ACC
Move to Accumulator
Operation:
Source → ACC
Assembler
Syntax:
MOVE.<size> <ea>, ACC
size = Long
Attributes:
Description: Moves a 32-bit value from a register or an immediate value into the
accumulator (ACC). The size of the operation must be specified as long.
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
0
C
0
-
-
0
0
OMC - not affected.
S/U
N
Z
V
C
-
-
-
-
-
not affected.
set if the most significant bit of the result is set, otherwise cleared.
set if the result is zero, otherwise cleared.
always cleared.
always cleared.
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
0
10
0
9
0
8
1
7
0
6
0
5
0
<EA>
MODE
REG
MOTOROLA
ColdFire2/2M User’s Manual
B-15
New MAC Instructions
Instruction Fields:
<ea> - Effective Address
ADDRESSING
MODE
ADDRESSING
MODE
MODE REGISTER
MODE REGISTER
Dn
An
000 reg.num:Dn
001 reg.num:An
(xxx).W
(xxx).L
-
-
-
-
(An)
-
-
-
-
-
-
-
-
-
-
#<data>
111
100
(An)+
-(An)
(d16,An)
(d8,An,Xn)
(d16,PC)
-
-
-
-
(d8,PC,Xn)
B-16
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
MOVE
MOVE
to CCR
to CCR
Move to Condition Code Register
Operation:
MACSR[4:0] → CCR[4:0]
Assembler
Syntax:
MOVE.<size> MACSR,CCR
size = Long
Attributes:
Description: Moves the indicator flags of the MAC status register (MACSR) into the
processor’s condition code cegister (CCR). The size of the operation must be specified as
long.
MAC Status Register:
Not affected
Processor Condition Codes:
X
-
N
*
Z
*
V
*
C
*
X
N
Z
V
C
-
-
-
-
-
not affected.
set to the value of MACSR bit 3, N.
set to the value of MACSR bit 2, Z.
set to the value of MACSR bit 1, V.
set to the value of MACSR bit 0, C.
Instruction Format
:
15
1
14
0
13
1
12
0
11
1
10
0
9
0
8
1
7
1
6
1
5
0
4
0
3
0
2
0
1
0
0
0
MOTOROLA
ColdFire2/2M User’s Manual
B-17
New MAC Instructions
MOVE
MOVE
to MACSR
to MACSR
Move to MAC Status Register
Operation:
Source → MACSR
Assembler
Syntax:
MOVE.<size> <ea>, MACSR
size = Long
Attributes:
Description: Moves the low-order byte of a 32-bit value from a register or an immediate
value into the MAC status register (MACSR). The size of the operation must be
specified as long.
MAC Status Register:
OMC S/U
-
-
N
*
Z
*
V
*
C
0
*
*
0
0
OMC - set to the value of bit 7 of the source operand.
S/U
N
Z
V
C
-
-
-
-
-
set to the value of bit 6 of the source operand.
set to the value of bit 3 of the source operand.
set to the value of bit 2 of the source operand.
set to the value of bit 1 of the source operand.
always cleared.
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
1
10
0
9
0
8
1
7
0
6
0
5
0
<EA>
MODE
REG
B-18
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
Instruction Fields:
<ea> - Effective Address
ADDRESSING
MODE
ADDRESSING
MODE
MODE REGISTER
MODE REGISTER
Dn
An
000 reg.num:Dn
001 reg.num:An
(xxx).W
(xxx).L
-
-
-
-
(An)
-
-
-
-
-
-
-
-
-
-
#<data>
111
100
(An)+
-(An)
(d16,An)
(d8,An,Xn)
(d16,PC)
-
-
-
-
(d8,PC,Xn)
MOTOROLA
ColdFire2/2M User’s Manual
B-19
New MAC Instructions
MOVE
MOVE
to MASK
to MASK
Move to Modulus Register
Operation:
Source → MASK
Assembler
Syntax:
MOVE.<size> <ea>, MASK
size = Long
Attributes:
Description: Moves the low-order word of a 32-bit value from a register or an immediate
value into the mask register (MASK). The size of the operation must be specified as
long.
MAC Status Register:
Not affected
Processor Condition Codes:
Not affected
Instruction Format:
15
1
14
0
13
1
12
0
11
1
10
1
9
0
8
1
7
0
6
0
5
0
<EA>
MODE
REG
Instruction Fields:
<ea> - Effective Address
ADDRESSING
MODE
ADDRESSING
MODE
MODE REGISTER
MODE REGISTER
Dn
An
000 reg.num:Dn
001 reg.num:An
(xxx).W
(xxx).L
-
-
-
-
(An)
-
-
-
-
-
-
-
-
-
-
#<data>
111
100
(An)+
-(An)
(d16,An)
(d8,An,Xn)
(d16,PC)
-
-
-
-
(d8,PC,Xn)
B-20
ColdFire2/2M User’s Manual
MOTOROLA
New MAC Instructions
B.4 OPERATION CODE MAP
All MAC instructions are mapped into line A, i.e. bits 15-12 of the instruction are 1010 ($A).
1. MAC
15
1
14
0
13
1
12
0
11
SZ
10
RY
9
9
9
8
0
0
7
0
6
5
0
4
0
3
3
3
2
2
2
1
1
1
0
0
0
RY
U/LX
RX
RX
-
-
SF
SF
U/LY
-
2. MSAC
15
1
14
0
13
1
12
0
11
SZ
10
RY
8
0
1
7
0
6
5
0
4
0
RY
U/LX
U/LY
-
3. MACL
15
1
14
13
1
12
0
11
10
8
0
0
7
1
6
5
4
<EA>
0
RY
RY
MODE
0
REG
RX
RY
RY
SZ
SF
SF
U/LY U/LX MAM
4. MSACL
15
1
14
0
13
1
12
0
11
10
9
8
0
1
7
1
6
5
4
3
2
1
0
<EA>
RW
RY
MODE
0
REG
SZ
U/LY U/LX MAM
RX
5. MOVE to ACC
15
1
14
0
13
1
12
0
11
0
10
0
9
0
8
1
7
0
6
0
5
5
5
0
0
0
<EA>
<EA>
<EA>
MODE
MODE
MODE
REG
REG
REG
6. MOVE to MACSR
15
1
14
0
13
1
12
0
11
1
10
0
9
0
8
1
7
0
6
0
7. MOVE to MASK
15
1
14
0
13
1
12
0
11
1
10
1
9
0
8
1
7
0
6
0
8. MOVE from ACC
15
1
14
0
13
1
12
0
11
0
10
0
9
0
8
1
7
1
6
0
5
0
4
0
3
0
RX
MOTOROLA
ColdFire2/2M User’s Manual
B-21
New MAC Instructions
9. MOVE from MACSR
15
1
14
0
13
1
12
0
11
1
10
0
9
0
8
1
7
1
6
0
5
0
4
0
3
3
0
0
0
RX
RX
10. MOVE from MASK
15
1
14
0
13
1
12
0
11
1
10
1
9
0
8
1
7
1
6
0
5
0
4
0
11. MOVE to CCR
15
1
14
0
13
1
12
0
11
0
10
0
9
0
8
1
7
0
6
0
5
<EA>
MODE
REG
B-22
ColdFire2/2M User’s Manual
MOTOROLA
INDEX
A
read control register (RCREG) 7-22
read debug module register (RDMREG)
7-24
read memory location (READ) 7-14
recommended connector 7-40
resume execution (GO) 7-21
sampling diagram 7-8
A0 - A7 1-12
AABR 7-29, 7-30, 7-32, 7-33, A-2, A-4, A-5
AATR 7-28, 7-30
ABLR/ABHR 7-28, 7-29
ACC 1-14, 6-2
access
serial interface 7-7
alternate master 3-5
emulator mode 3-5
interrupt acknowledge mode 3-5
normal mode 3-4
serial transfer diagram 7-8
write A/D register (WAREG/WDREG)
7-13
write control register (WCREG) 7-23
write debug module register (WDMREG)
7-25
access control
programming model 5-8
registers 5-8, 5-9, A-3
access error exception 4-7
accumulator (ACC) 1-14, 6-2
ACR 5-8, 5-9, A-3
write memory location (WRITE) 7-16
BKPTB 2-11, 7-1, 7-6, 7-7
branch indication on PST 7-3
bus arbitration 3-30
address error exception 4-8
address registers (A0 – A6) 1-12
address space 2-3, 3-1, 3-4
addressing mode summary 1-18
alternate master 1-9
alternate master access 3-5
arbitration 3-30
arbitration algorithm 3-30
autovectored interrupts 4-12
programming model 3-31
bus errors 3-28
C
cache
See instruction cache
cacheability 5-5
CACR 3-31, 5-6, A-3
CCR 1-12, 1-13, A-3
CLK 2-6
B
clock (CLK) 2-6
coherency 5-6
coldfire system diagram 1-8
coldfire2 1-1
coldfire2m 1-1, 1-13, 6-1, B-1
compiled RAM 5-1, 5-4
condition code register (CCR) 1-13, A-3
configuration encoding 2-8, 2-10, 2-11, 5-3,
5-12, 5-16
background debug mode
See BDM
BDM 7-5
command format 7-10
command sequence diagram 7-11, 7-12
command set 7-9
connector 7-39
CPU32 7-40
dump memory block (DUMP) 7-17
fill memory block (FILL) 7-19
no operation (NOP) 7-21
read A/D Register (RAREG/RDREG)
7-13
core block diagram 1-10
CPU halt 7-5, 7-6
CSR 7-36, 7-37, A-4
MOTOROLA
COLDFIRE2/2M USER’S MANUAL
Index-1
D
break point (BKPTB) 2-11, 7-1
debug data (DDATA) 2-12, 7-2
development serial clock (DSCLK)
2-12, 7-2
D0 - D7 1-12
data formats 1-16
data registers (D0 – D7) 1-12
data sheet 10-6
data transfer mechanism 3-4
data transfers 3-6
DBR/DBMR 7-28, 7-33
DDATA 2-12, 7-2, 7-3, 7-4, 7-5
debug module 7-1
BDM 7-5
development serial input (DSI) 2-12,
7-2
development serial output (DSO)
2-12, 7-2
processor status (PST) 2-12, 7-2
theory of operation 7-26
See also registers, signals
definitions 10-1
development cycle 1-5
diagrams
command set 7-9
DUMP 7-17
FILL 7-19
GO 7-21
NOP 7-21
RAREG/RDREG 7-13
RCREG 7-22
RDMREG 7-24
READ 7-14
serial interface 7-7
WAREG/WDREG 7-13
WCREG 7-23
WDMREG 7-25
WRITE 7-16
BDM command sequence 7-12
BDM sampling 7-8
BDM serial transfer 7-8
bus exception 3-29
coldfire system 1-8
core block 1-10
design system overview 1-7
example instruction cache interface 5-2
example ROM interface 5-11
example SRAM interface 5-15
flexcore integrated processor 1-3
instruction cache data read 8-8
instruction cache data write 8-7
instruction cache tag read 8-5
instruction cache tag write 8-4
integer address formats 1-17
integer data formats 1-16
interrupt acknowledge 3-24, 3-26
KTA mode 8-10
line read transfer 3-13
line write transfer 3-16, 3-17
MAC flow 6-2
memory operand addressing 1-18
misaligned transfer 3-19
processor status 7-4
processor/debug module interface 7-1
read transfer 3-8
recommended BDM connector 7-40
reset 3-30
ROM read 8-12
signals block 2-1
SRAM read 8-15
concurrent operation 7-39
CPU halt 7-6
emulator mode 7-27, 7-38
hardware reuse 7-28
interrupt 4-10, 7-26
programming model 7-28
real-time support 7-26
real-time trace 7-2
registers
address attribute (AATR) 7-30
address attribute breakpoint (AABR)
7-29, 7-30, 7-32, 7-33, A-2,
A-4, A-5
address breakpoint (ABLR, ABHR)
7-29
configuration/status register (CSR)
7-36, 7-37, A-4
data breakpoint (DBR, DBMR) 7-33
program counter breakpoint (PBR,
PBMR) 7-32
trigger definition (TDR) 7-34, A-6
signals 7-1
SRAM write 8-14
Index-2
ColdFire2/2M User’s Manual
MOTOROLA
wait state 3-21
write transfer 3-10
DSCLK 2-12, 7-2, 7-8
DSI 2-12, 7-2
exception processing 4-2
interrupt acknowledge 3-23
line read transfer 3-12
line write transfer 3-15
read transfer 3-7
DSO 2-12, 7-2
DUMP 7-17
write transfer 3-9
format error exceptions 4-10
freezing the instruction cache 5-7
E
electrical chacteristics 10-1
emulator mode 7-5, 7-27, 7-38
emulator mode access 3-5
enhanced integer multiply instructions B-1
exception processing 4-1, 7-5
flowchart 4-2
G
general control signals 2-6
clock (CLK) 2-6
interrupt priority level (IPLB) 2-6
GO 7-21
overview 4-1
H
self-aligning stack 4-4
stack frame definition 4-3
exception vector table 4-5
exceptions 4-7
HALT 7-6
HALT instruction 7-5
hard module 1-4
access error 4-7
address error 4-8
I
bus cycle diagram 3-29
control cycles 3-27
debug interrupt 4-10, 7-26
format error 4-10
illegal instruction 4-9
interrupt 4-10
IACK_68K 2-3, 2-5, 2-6, 3-1, 3-3, 3-4, 3-22
ICH_ADDR 2-7, 5-2
ICH_SZ 2-8, 5-3
ICHD_CSB 2-7, 5-2
ICHD_DI 2-7, 5-2
ICHD_DO 2-7, 5-2
priorities 4-6
ICHD_RWB 2-7, 5-3
ICHD_ST 2-7, 5-2
ICHT_CSB 2-8, 5-3
ICHT_DI 2-8, 5-3
ICHT_DO 2-8, 5-3
ICHT_RWB 2-9, 5-4
ICHT_ST 2-9, 5-4
illegal instruction exception 4-9
instruction cache 1-10, 5-1
cacheability 5-5
privilege violation 4-9
reset 4-7
simultaneous 4-6
trace 4-9
TRAP instruction 4-10
unimplemented opcode 4-9
vector number 4-4, 4-5
external bus 1-9
F
coherency 5-6
fault-on-fault halt 3-29, 4-6, 7-6
FILL 7-19
flexcore 1-8
configuration encoding 2-8, 5-3
data RAM testing 8-6
example interface diagram 5-2
freezing 5-7
interaction with other modules 5-4
invalidating 5-5, 5-7
advantages 1-4
development cycle 1-5
integrated processor diagram 1-3
integrated processors 1-2
module types 1-4
KTA mode testing 8-9
line fill encoding 5-8
flowcharts
MOTOROLA
ColdFire2/2M User’s Manual
Index-3
miss fetch algorithm 5-4, 5-8
physical organization 5-4
programming model 5-6
registers
interrupt priority level (IPLB) 2-6, 4-10
interrupts 4-10
autovectored 4-12
debug 4-10, 7-26
cache control (CACR) 5-6, A-3
reset 5-6
signals 5-1
level seven 4-11
spurious 3-27, 4-12
uninitialized 4-12
address bus (ICH_ADDR) 2-7, 5-2
cache tag output bus (ICHT_DO)
2-8, 5-3
data chip select (ICHD_CSB) 2-7,
5-2
data input bus (ICHD_DI) 2-7, 5-2
data output bus (ICHD_DO) 2-7, 5-2
data read/write (ICHD_RWB) 2-7,
5-3
invalidating cache entries 5-5, 5-7
IPLB 2-6, 4-10
K
KTA mode 8-9
L
level seven interrupts 4-11
line access patterns 3-11
line fills 5-4
line read transfer
diagram 3-13
data strobe (ICHD_ST) 2-7, 5-2
size(ICH_SZ) 2-8, 5-3
tag chip select (ICHT_CSB) 2-8, 5-3
tag input bus (ICHT_DI) 2-8, 5-3
tag read/write (ICHT_RWB) 2-9, 5-4
tag strobe (ICHT_ST) 2-9, 5-4
tag RAM testing 8-3
flowchart 3-12
line write transfer
diagram 3-16, 3-17
flowchart 3-15
write protection 5-8
See also registers, signals
instruction execution timing 9-1
assumptions 9-1
M
MAC 9-8, B-2
branch 9-8
MAC 9-8
miscellaneous 9-7
MOVE 9-2
one operand 9-4
two operand 9-5
MAC Status Register (MACSR) 6-2
MAC status register (MACSR) 1-14
MAC unit 6-1
enhanced integer multiply instructions
B-1
instruction set summary 6-5
instruction timing 9-8
introduction 6-1
new MAC instructions B-1
new register instructions B-12
overflow mode 6-3, 6-4
programming model 1-13, 6-2
registers
instruction set summary 1-19, 6-5
integer data formats 1-16
integer programming model 1-11
integrated memories 5-1
testing 8-1
integrated memory test signals 2-12
integrated processors 1-2
interrupt acknowledge
diagram 3-24, 3-26
ACC 6-2
MACSR 6-2
MASK 6-3
flowchart 3-23
interrupt acknowledge access 3-5
interrupt acknowledge bus cycle 3-22
interrupt acknowledge mode 2-3, 2-5, 2-6,
3-1, 3-3, 3-4, 3-22
saturation mode 6-3, 6-4
shifting 6-4
MACL 9-8, B-4
MACSR 1-14, 6-2
Index-4
ColdFire2/2M User’s Manual
MOTOROLA
MADDR 2-3, 3-1, 3-8, 3-10, 3-13, 3-16,
3-24, 3-26
write data output enable (MWDATAOE)
2-6, 3-4
MARB 1-10
MARBC 2-3, 3-1
MASK 6-3
mask (MASK) 6-3
See also registers, signals
memory operand addressing diagram 1-18
memory organization 1-17
MFRZB 2-4, 3-2
mask addressing mode 6-4
master bus 1-8, 3-1
MIE 2-4, 3-2, 3-8, 3-13, 3-25, 3-27
misaligned operands 3-18
misaligned transfer diagram 3-19
misalignment unit 3-18
miss fetch algorithm 5-4, 5-8
MKILLB 2-4, 3-2
arbitration 1-10, 3-30
arbitration algorithm 3-30
bus errors 3-28
data transfer mechanism 3-4
data transfers 3-6
module types 1-4
exception control cycles 3-27
line read transfers 3-11
line write transfers 3-14
misaligned operands 3-18
normal read transfers 3-6
normal write transfers 3-9
requirements for read transfer 3-5
requirements for write transfers 3-6
reset 3-29
MOVE from ACC 9-7, B-13
MOVE from MACSR 9-7, B-14
MOVE from MASK 9-7, B-15
MOVE to ACC 9-7, B-16
MOVE to CCR 9-7, B-18
MOVE to MACSR B-19
Move to MACSR 9-7
MOVE to MASK 9-7, B-21
MOVEC instruction 3-31, 5-6, 5-8, 5-12,
5-17, 7-22, A-1
signals 3-1
68K IACK mode enable (IACK_68K)
2-3, 2-5, 2-6, 3-1, 3-3, 3-4,
3-22
abiter control (MARBC) 2-3, 3-1
address bus (MADDR) 2-3, 3-1
freeze (MFRZB) 2-4, 3-2
kill (MKILLB) 2-4, 3-2
read data bus (MRDATA) 2-4, 3-2
MRDATA 2-4, 3-2, 3-8, 3-13, 3-25, 3-27
MRSTB 2-4, 3-2
MRWB 2-4, 3-2, 3-8, 3-10, 3-13, 3-16, 3-24,
3-26
MSAC 9-8, B-7
MSACL 9-8, B-9
MSIZ 2-4, 3-2, 3-8, 3-10, 3-13, 3-16, 3-24,
3-26
read data input enable (MIE) 2-4, 3-2 MTAB 2-5, 3-2, 3-8, 3-13, 3-16, 3-25, 3-27
read/write (MRWB) 2-4, 3-2
reset (MRSTB) 2-4, 3-2
MTEAB 2-5, 3-3
MTM 2-5, 3-3, 3-13
size (MSIZ) 2-4, 3-2
transfer acknowledge (MTAB) 2-5,
3-2
transfer error acknowledge (MTEAB)
2-5, 3-3
MTSB 2-6, 3-3, 3-8, 3-10, 3-13, 3-16, 3-24,
3-26
MTT 2-6, 3-3, 3-8, 3-10, 3-13, 3-16, 3-24,
3-26
MULS and MULU 9-5, B-1
multiple exceptions 4-6
multiply-accumulate unit
See MAC unit
MWDATA 2-6, 3-4, 3-10, 3-16
MWDATAOE 2-6, 3-4, 3-10, 3-16
transfer modifier (MTM) 2-5, 3-3
transfer start (MTSB) 2-6, 3-3
transfer type (MTT) 2-6, 3-3
write data bus (MWDATA) 2-6, 3-4
transfer modifier encoding 2-5, 3-3
transfer size encoding 2-5, 3-2
transfer type 3-4
N
transfer type encoding 2-6, 3-4
new MAC instructions B-1
MOTOROLA
ColdFire2/2M User’s Manual
Index-5
new register instructions B-12
NOP 4-8, 7-21
normal access 3-4
real-time debug support 7-26
real-time trace 7-2
registers
notational conventions 1-19
access control
ACR 1-15, 5-8, 5-9, A-3
access methods A-1
debug module
O
overflow mode 6-3, 6-4
P
AABR 7-29, 7-30, 7-32, 7-33, A-2,
A-4, A-5
AATR 7-28, 7-30
ABLR/ABHR 7-28, 7-29
CSR 7-36, 7-37, A-4
DBR/DBMR 7-28, 7-33
PBR/PBMR 7-32
parameterizable module 1-5
PBMR 7-32
PBR 7-32
PC 1-12
performance 3-20
TDR 7-34, A-6
pipeline stalls 3-20
power 2-4, 3-2
instruction cache
CACR 1-15, 5-6, A-3
integer unit
privilege mode 1-15, 3-4, 4-2, 7-3
privilege violation exception 4-9
processor status 2-12, 7-2, 7-3
processor status diagram 7-4
processor status encoding 7-3
program counter (PC) 1-12
programming model 1-11
access control 5-8
A0 - A6 1-12
CCR 1-13, A-3
D0 - D7 1-12
PC 1-12
SP 1-12
MAC unit
ACC 1-14, 6-2
bus arbitration 3-31
debug module 7-28
instruction cache 5-6
integer 1-11
MAC unit 1-13, 6-2
ROM module 5-12
MACSR 1-14, 6-2
MASK 6-3
ROM module
ROMBAR0 1-15, 5-12, A-6
SRAM module
RAMBAR0 1-15, 5-17, A-5
summary A-1
SRAM module 5-16
supervisor 1-14
supervisor
PST 2-12, 7-2, 7-3
PULSE instruction 2-12, 7-2, 7-3
SR 1-15, 4-2, A-6
VBR 1-15, 4-6
reset 2-4, 3-2, 3-29, 3-30, 4-7, 5-6, 5-8,
5-12, 5-17
R
ROM module 1-11, 5-10
configuration encoding 2-10, 5-12
example interface diagrams 5-11
programming model 5-12
registers
RAMBAR0 5-17, A-5
RAREG A-1
RAREG/RDREG 7-13
RCREG 7-22, A-1
RDMREG 7-24, A-1
READ 7-14
ROM base address (ROMBAR0)
5-12, A-6
signals 5-10
read transfer
diagram 3-8
flowchart 3-7
read transfers 3-6, 3-11
activate (ROM_ACTB) 2-10, 5-12
address bus (ROM_ADDR) 2-9, 5-11
Index-6
ColdFire2/2M User’s Manual
MOTOROLA
data output bus (ROM_DO) 2-9, 5-11
enable (ROM_ENB) 2-9, 5-11
size (ROM_SZ) 2-9, 5-12
ICHD_DI 2-7, 5-2
ICHD_DO 2-7, 5-2
ICHD_RWB 2-7, 5-3
ICHD_ST 2-7, 5-2
testing 8-11
See also registers, signals
ROM_ACTB 2-10, 5-12
ROM_ADDR 2-9, 5-11
ROM_DO 2-9, 5-11
ROM_ENB 2-9, 5-11
ROM_SZ 2-9, 5-12
ICHT_CSB 2-8, 5-3
ICHT_DI 2-8, 5-3
ICHT_DO 2-8, 5-3
ICHT_RWB 2-9, 5-4
ICHT_ST 2-9, 5-4
master bus 3-1
ROMBAR0 5-12, A-6
RTE instruction 2-12, 4-6, 4-10, 7-2, 7-4,
7-5, 7-27
IACK_68K 2-3, 2-5, 2-6, 3-1, 3-3,
3-4, 3-22
MADDR 2-3, 3-1
MARBC 2-3, 3-1
MFRZB 2-4, 3-2
S
MIE 2-4, 3-2
saturation mode 6-3, 6-4
SBC 1-11, 3-6
scan signals
MKILLB 2-4, 3-2, 3-20
MRDATA 2-4, 3-2, 3-5, 3-6
MRSTB 2-4, 3-2, 3-30
MRWB 2-4, 3-2
MSIZ 2-4, 3-2, 3-6, 3-9
MTAB 2-5, 3-2, 3-27
MTEAB 2-5, 3-3, 3-28
MTM 2-5, 3-3, 3-4
enable (SCAN_ENABLE) 2-14, 8-16
exercise array (SCAN_XARRAY) 2-14,
8-16
input (SCAN_IN) 2-14, 8-16
mode (SCAN_MODE) 2-14, 8-17
output (SCAN_OUT) 2-14, 8-17
SCAN_ENABLE 2-14, 8-16
SCAN_IN 2-14, 8-16
SCAN_MODE 2-14, 8-17
SCAN_OUT 2-14, 8-17
SCAN_XARRAY 2-14, 8-16
shifting operations 6-4
signals
MTSB 2-6, 3-3
MTT 2-6, 3-3, 3-4
MWDATA 2-6, 3-4, 3-6, 3-9
MWDATAOE 2-6, 3-4
ROM module 5-10
ROM_ACTB 2-10, 5-12
ROM_ADDR 2-9, 5-11
ROM_DO 2-9, 5-11
ROM_ENB 2-9, 5-11
ROM_SZ 2-9, 5-12
scan
summary 2-1
block diagram 2-1
debug module 7-1
BKPTB 2-11, 7-1
SCAN_ENABLE 2-14, 8-16
SCAN_IN 2-14, 8-16
SCAN_MODE 2-14, 8-17
SCAN_OUT 2-14, 8-17
SCAN_XARRAY 2-14, 8-16
SRAM module 5-14
SRAM_ADDR 2-10, 5-15
SRAM_CSB 2-10, 5-16
SRAM_DI 2-11, 5-16
SRAM_DO 2-11, 5-16
SRAM_RWB 2-11, 5-16
SRAM_ST 2-11, 5-16
DDATA 2-12, 7-2
DSCLK 2-12, 7-2
DSI 2-12, 7-2
DSO 2-12, 7-2
PST 2-12, 3-29, 4-6, 7-2
general control 2-6
CLK 2-6
IPLB 2-6, 4-10
instruction cache 5-1
ICH_ADDR 2-7, 5-2
ICH_SZ 2-8, 5-3
ICHD_CSB 2-7, 5-2
MOTOROLA
ColdFire2/2M User’s Manual
Index-7
SRAM_SZ 2-11, 5-16
test bus 2-12
SRAM_DO 2-11, 5-16
SRAM_RWB 2-11, 5-16
TEST_ADDR 2-13, 8-1, 8-4
TEST_CTRL 2-13, 8-1, 8-4
TEST_ICH_RHIT 2-13, 8-2, 8-6,
8-11
SRAM_ST 2-11, 5-16
SRAM_SZ 2-11, 5-16
stack frame 4-3
stack pointer (A7,SP) 1-12
status register (SR) 1-15, 4-2, A-6
STOP instruction 4-9, 7-5, 7-7
supervisor programming model 1-14
system bus controller (SBC) 1-11, 3-6
TEST_IDATA_RD 2-13, 8-1, 8-9
TEST_IDATA_WRT 2-13, 8-2, 8-7
TEST_ITAG_WRT 2-13, 8-2, 8-4
TEST_IVLD_INH 2-13, 8-2
TEST_KTA 2-13, 8-2, 8-11
TEST_MODE 2-13, 8-2, 8-3
TEST_READ 2-13, 8-2, 8-9
TEST_ROM_RD 2-13, 8-2, 8-12
TEST_SRAM_RD 2-13, 8-2, 8-16
TEST_SRAM_WRT 2-13, 8-2, 8-14
TEST_WR_INH 2-13, 8-2
signed/unsigned MAC operations 6-3
slave bus 1-9
slave modules 1-11
soft module 1-4
SP 1-12, 4-4
spurious interrupt 3-27
spurious interrupts 4-12
SR 1-15, 3-4, 4-2, 4-10, A-6
SRAM module 1-11, 5-14
configuration encoding 2-11, 5-16
example interface diagram 5-15
programming model 5-16
registers
T
TDR 7-34, A-6
test bus 8-1
signals 2-12
address bus (TEST_ADDR) 2-13,
8-1, 8-4
control (TEST_CTRL) 2-13, 8-1, 8-4
IDATA read (TEST_IDATA_RD)
2-13, 8-1, 8-9
IDATA write (TEST_IDATA_WRT)
2-13, 8-2, 8-7
instruction cache read hit
(TEST_ICH_RHIT) 2-13, 8-2,
8-6, 8-11
invalidate inhibit (TEST_IVLD_INH)
2-13, 8-2
ITAG write (TEST_ITAG_WRT)
2-13, 8-2, 8-4
KTA mode enable (TEST_KTA)
2-13, 8-2, 8-11
mode enable (TEST_MODE) 2-13,
8-2, 8-3
read (TEST_RD) 2-13, 8-2, 8-9
ROM read (TEST_ROM_RD) 2-13,
8-2, 8-12
SRAM read (TEST_SRAM_RD)
2-13, 8-2, 8-16
SRAM write (TEST_SRAM_WRT)
2-13, 8-2, 8-14
write inhibit (TEST_WR_INH) 2-13,
8-2
base address (RAMBAR0) 5-17, A-5
signals 5-14
address bus (SRAM_ADDR) 2-10,
5-15
chip select (SRAM_CSB) 2-10, 5-16
data input bus (SRAM_DI) 2-11, 5-16
data output bus (SRAM_DO) 2-11,
5-16
read/write (SRAM_RWB) 2-11, 5-16
size (SRAM_SZ) 2-11, 5-16
strobe (SRAM_ST) 2-11, 5-16
testing 8-13
write protection 5-13, 5-17
See also registers, signals
SRAM_ADDR 2-10, 5-15
SRAM_CSB 2-10, 5-16
test mode 8-3
TEST_ADDR 2-13, 8-1, 8-4
TEST_CTRL 2-13, 8-1, 8-4
TEST_ICH_RHIT 2-13, 8-2, 8-6, 8-11
TEST_IDATA_RD 2-13, 8-1, 8-9
SRAM_DI 2-11, 5-16
Index-8
ColdFire2/2M User’s Manual
MOTOROLA
TEST_IDATA_WRT 2-13, 8-2, 8-7
TEST_ITAG_WRT 2-13, 8-2, 8-4
TEST_IVLD_INH 2-13, 8-2
TEST_KTA 2-13, 8-2, 8-11
TEST_MODE 2-13, 8-2, 8-3
TEST_READ 2-13, 8-2, 8-9
TEST_ROM_RD 2-13, 8-2, 8-12
TEST_SRAM_RD 2-13, 8-2, 8-16
TEST_SRAM_WRT 2-13, 8-2, 8-14
TEST_WR_INH 2-13, 8-2
testing
U
unimplemented opcode exception 4-9
uninitialized interrupts 4-12
V
variant addressing 7-3, 7-4
VBR 1-15, 4-6
vector base register (VBR) 1-15, 4-6
vector number 4-5
W
cache data RAM 8-6
cache tag RAM 8-3
integrated memories 8-1
KTA mode 8-9
ROM 8-11
SRAM 8-13
wait state diagram 3-21
wait states 3-10, 3-17, 3-20
WAREG A-1
WAREG/WDREG 7-13
WCREG 7-23, A-1
WDDATA instruction 2-12, 7-2, 7-3
WDEBUG instruction A-1
WDMREG 7-25, A-1
WRITE 7-16
write protection 5-8, 5-10, 5-13, 5-17
write transfer
trace exception 4-9
trace mode 4-2, 4-9
transfer modifier encoding 2-5, 3-3
transfer size encoding 2-5, 3-2
transfer type 3-4
transfer type encoding 2-6, 3-4
transfers
diagram 3-10
flowchart 3-9
write transfers 3-9, 3-14
line read 3-11
line write 3-14
normal read 3-6
normal write 3-9
TRAP instruction exceptions 4-9, 4-10
MOTOROLA
ColdFire2/2M User’s Manual
Index-9
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