COP8TAC5 [NSC]

8-Bit CMOS ROM Microcontroller with 2k or 4k Memory; 8位CMOS微控制器的ROM与2K或4K内存
COP8TAC5
型号: COP8TAC5
厂家: National Semiconductor    National Semiconductor
描述:

8-Bit CMOS ROM Microcontroller with 2k or 4k Memory
8位CMOS微控制器的ROM与2K或4K内存

微控制器
文件: 总54页 (文件大小:694K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
August 2004  
COP8TAB5/TAC5  
8-Bit CMOS ROM Microcontroller with 2k or 4k Memory  
Development is supported through the use of a compatible  
1.0 General Description  
Flash based device (COP8TAB9/TAC9) which provides  
The COP8TAB5/TAC5 microcontrollers are highly integrated  
identical features plus In-System programmable Flash  
COP8 Feature core devices, with 2k or 4k ROM memory  
Memory and reprogrammability. The Flash device is usable  
in the emulation tools, and supports this device.  
and advanced features. These single-chip CMOS devices  
are suited for applications requiring a full featured controller  
with moderate memory and low EMI.  
Device included in this datasheet:  
ROM Program  
Memory (bytes)  
RAM  
(bytes)  
128  
I/O  
Pins  
Device  
Packages  
Temperature  
COP8TAB5  
COP8TAC5  
2k  
4k  
16, 24 or 40  
20 and 28 SOIC WIDE,  
44 LLP  
−40˚C to +85˚C  
128  
— Master Mode and Slave Mode  
— Full Master Mode Capability  
— Bus Speed Up To 400KBits/Sec  
— Low Power Mode With Wake-Up Detection  
— Optional 1.8V ACCESS.Bus Compatibility  
n Eight multi-source vectored interrupts servicing:  
— External Interrupt  
2.0 Features  
KEY FEATURES  
n 2k or 4k bytes ROM Program Memory  
n 128 bytes volatile RAM  
n Crystal Oscillator at 15 MHz or Integrated RC Oscillator  
at 10MHz  
— Idle Timer T0  
n Clock Prescaler For Adjusting Power Dissipation to  
Processing Requirements  
n Power-On Reset  
n HALT/IDLE Power Save Modes  
n One 16-bit timer:  
— Processor Independent PWM mode  
— External Event counter mode  
— Input Capture mode  
— One Timers (with 2 interrupts)  
— MICROWIRE/PLUS Serial peripheral interface  
— ACCESS.Bus/I2C/SMBus compatible Synchronous  
Serial Interface  
— Multi-Input Wake-Up  
— Software Trap  
n Idle Timer with programmable interrupt interval  
n 8-bit Stack Pointer SP (stack in RAM)  
n Two 8-bit Register Indirect Data Memory Pointers  
n True bit manipulation  
n High Current I/Os  
@
— 10 mA 0.4V  
OTHER FEATURES  
n WATCHDOG and Clock Monitor logic  
n Software selectable I/O options  
— TRI-STATE Output/High Impedance Input  
— Push-Pull Output  
n Single supply operation:  
— 2.25V–2.75V  
n Quiet Design (low radiated emissions)  
n Multi-Input Wake-Up with optional interrupts  
n MICROWIRE/PLUS (Serial Peripheral Interface  
Compatible)  
— Weak Pull Up Input  
n Schmitt trigger inputs on I/O ports  
n Temperature range: –40˚C to +85˚C  
n Packaging: 20 and 28 SOIC and 44 LLP  
n ACCESS.Bus Synchronous Serial Interface (compatible  
with I2C and SMBus  
)
2
I
C® is a registered trademark of Phillips Corporation.  
SMBus is a trademark of Intel Corporation.  
© 2004 National Semiconductor Corporation  
DS200917  
www.national.com  
3.0 Block Diagram  
20091701  
4.0 Ordering Information  
Part Numbering Scheme  
COP8  
TA  
C
5
H
LQ  
8
Family and  
Feature Set  
Indicator  
Program  
Memory  
Size  
Program  
Memory  
Type  
Package  
Type  
No. Of Pins  
Temperature  
B = 2k  
C = 4k  
5 = Masked ROM C = 20 Pin  
LQ = LLP  
MW = SOIC WIDE  
8 = -40 to +85˚C  
9 = Flash  
E = 28 Pin  
H = 44 Pin  
NOTE: The user, utilizing the COP8TAx9 Flash based de-  
vices during development, is cautioned to ensure that code  
contains NO calls to Boot ROM functions prior to submission  
for ROM generation. Instances of the JSRB instruction in  
ROM based devices will be executed as a JSR instruction to  
a location in the first 256 bytes of Program Memory.  
differences between the devices. For this reason, the user is  
strongly advised to obtain masked ROM prototype devices  
before committing to production quantities. This will allow the  
user to ensure there are no unexpected differences between  
Flash and ROM devices within the application.  
Flash and ROM devices are not 100% identical. The execu-  
tion of the JSRB instruction is an example of the potential  
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2
Table of Contents  
1.0 General Description ..................................................................................................................................... 1  
2.0 Features ....................................................................................................................................................... 1  
3.0 Block Diagram .............................................................................................................................................. 2  
4.0 Ordering Information .................................................................................................................................... 2  
5.0 Connection Diagrams ................................................................................................................................... 5  
6.0 Architectural Overview ................................................................................................................................. 7  
6.1 EMI REDUCTION ...................................................................................................................................... 7  
6.2 ARCHITECTURE ..................................................................................................................................... 7  
6.3 INSTRUCTION SET ................................................................................................................................. 7  
6.3.1 Key Instruction Set Features ............................................................................................................... 7  
6.3.2 Single Byte/Single Cycle Code Execution ......................................................................................... 7  
6.3.3 Many Single-Byte, Multi-Function Instructions .................................................................................... 7  
6.3.4 Bit-Level Control .................................................................................................................................. 7  
6.3.5 Register Set ......................................................................................................................................... 7  
6.4 PACKAGING/PIN EFFICIENCY ................................................................................................................ 7  
7.0 Absolute Maximum Ratings ......................................................................................................................... 8  
8.0 Electrical Characteristics .............................................................................................................................. 8  
9.0 Pin Descriptions ......................................................................................................................................... 11  
10.0 Functional Description .............................................................................................................................. 13  
10.1 CPU REGISTERS ................................................................................................................................. 13  
10.2 PROGRAM MEMORY ........................................................................................................................... 14  
10.3 DATA MEMORY .................................................................................................................................... 14  
10.4 OPTION REGISTER ............................................................................................................................. 14  
10.5 RESET ................................................................................................................................................... 15  
10.5.1 External Reset ................................................................................................................................. 15  
10.5.2 On-Chip Power-On Reset ................................................................................................................ 15  
10.6 OSCILLATOR CIRCUITS ...................................................................................................................... 16  
10.6.1 Crystal Oscillator .............................................................................................................................. 16  
10.6.2 R/C Oscillator ................................................................................................................................... 16  
10.6.3 External Oscillator ............................................................................................................................ 17  
10.6.4 Clock Prescaler ................................................................................................................................ 17  
10.7 CONTROL REGISTERS ....................................................................................................................... 18  
10.7.1 CNTRL Register (Address X'00EE) ................................................................................................. 18  
10.7.2 PSW Register (Address X'00EF) ..................................................................................................... 18  
10.7.3 ICNTRL Register (Address X'00E8) ................................................................................................ 18  
10.7.4 ITMR Register (Address X'00CF) .................................................................................................... 18  
11.0 Timers ....................................................................................................................................................... 18  
11.1 TIMER T0 (IDLE TIMER) ....................................................................................................................... 18  
11.1.1 ITMR Register .................................................................................................................................. 19  
11.2 TIMER T1 .............................................................................................................................................. 19  
11.3 MODE 1. PROCESSOR INDEPENDENT PWM MODE ....................................................................... 19  
11.4 MODE 2. EXTERNAL EVENT COUNTER MODE ................................................................................ 19  
11.5 MODE 3. INPUT CAPTURE MODE ...................................................................................................... 21  
11.6 TIMER CONTROL FLAGS .................................................................................................................... 22  
12.0 Power Save Modes .................................................................................................................................. 22  
12.1 HALT MODE .......................................................................................................................................... 22  
12.2 IDLE MODE ........................................................................................................................................... 23  
12.3 MULTI-INPUT WAKE-UP ...................................................................................................................... 24  
13.0 Interrupts .................................................................................................................................................. 25  
13.1 INTRODUCTION ................................................................................................................................... 25  
13.2 MASKABLE INTERRUPTS ................................................................................................................... 26  
13.3 VIS INSTRUCTION ............................................................................................................................... 27  
13.3.1 VIS Execution .................................................................................................................................. 28  
13.4 NON-MASKABLE INTERRUPT ............................................................................................................ 29  
13.4.1 Pending Flag .................................................................................................................................... 29  
13.4.2 Software Trap .................................................................................................................................. 29  
13.4.2.1 Programming Example: External Interrupt ................................................................................. 30  
13.5 PORT C AND PORT L INTERRUPTS .................................................................................................. 31  
13.6 INTERRUPT SUMMARY ....................................................................................................................... 31  
14.0 WATCHDOG/Clock Monitor ..................................................................................................................... 31  
14.1 CLOCK MONITOR ................................................................................................................................ 32  
14.2 WATCHDOG/CLOCK MONITOR OPERATION .................................................................................... 32  
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Table of Contents (Continued)  
14.3 WATCHDOG AND CLOCK MONITOR SUMMARY .............................................................................. 32  
14.4 DETECTION OF ILLEGAL CONDITIONS ............................................................................................ 33  
15.0 MICROWIRE/PLUS .................................................................................................................................. 33  
15.1 MICROWIRE/PLUS OPERATION ......................................................................................................... 33  
15.2 MICROWIRE/PLUS MASTER MODE OPERATION ............................................................................. 34  
15.3 MICROWIRE/PLUS SLAVE MODE OPERATION ................................................................................ 34  
15.4 ALTERNATE SK PHASE OPERATION AND SK IDLE POLARITY ...................................................... 34  
16.0 ACCESS.Bus Interface ............................................................................................................................ 36  
16.1 DATA TRANSACTIONS ........................................................................................................................ 36  
16.1.1 Start and Stop .................................................................................................................................. 37  
16.1.2 Acknowledge Cycle .......................................................................................................................... 37  
16.1.3 Addressing Transfer Formats .......................................................................................................... 37  
16.2 BUS ARBITRATION .............................................................................................................................. 37  
16.3 POWER SAVE MODES ........................................................................................................................ 37  
16.4 SDA AND SCL DRIVER CONFIGURATION ......................................................................................... 37  
16.5 ACB SERIAL DATA REGISTER (ACBSDA) .......................................................................................... 38  
16.6 ACB STATUS REGISTER (ACBST) ..................................................................................................... 38  
16.7 ACB CONTROL STATUS REGISTER (ACBCST) ................................................................................ 38  
16.8 ACB CONTROL 1 REGISTER (ACBCTL1) .......................................................................................... 38  
16.9 ACB CONTROL REGISTER 2 (ACBCTL2) .......................................................................................... 39  
16.10 ACB OWN ADDRESS REGISTER (ACBADDR) ................................................................................ 39  
17.0 Memory Map ............................................................................................................................................ 39  
18.0 Instruction Set .......................................................................................................................................... 40  
18.1 INTRODUCTION ................................................................................................................................... 40  
18.2 INSTRUCTION FEATURES .................................................................................................................. 40  
18.3 ADDRESSING MODES ......................................................................................................................... 40  
18.3.1 Operand Addressing Modes ............................................................................................................ 40  
18.3.2 Tranfer-of-Control Addressing Modes .............................................................................................. 41  
18.4 INSTRUCTION TYPES ......................................................................................................................... 42  
18.4.1 Arithmetic Instructions ...................................................................................................................... 42  
18.4.2 Transfer-of-Control Instructions ....................................................................................................... 42  
18.4.3 Load and Exchange Instructions ..................................................................................................... 43  
18.4.4 Logical Instructions .......................................................................................................................... 43  
18.4.5 Accumulator Bit Manipulation Instructions ....................................................................................... 43  
18.4.6 Stack Control Instructions ................................................................................................................ 43  
18.4.7 Memory Bit Manipulation Instructions ............................................................................................. 43  
18.4.8 Conditional Instructions ................................................................................................................... 43  
18.4.9 No-Operation Instruction .................................................................................................................. 43  
18.5 REGISTER AND SYMBOL DEFINITION .............................................................................................. 43  
18.6 INSTRUCTION SET SUMMARY .......................................................................................................... 44  
18.7 INSTRUCTION EXECUTION TIME ...................................................................................................... 45  
19.0 Development Support ............................................................................................................................. 48  
19.1 TOOLS ORDERING NUMBERS FOR THE COP8TA 2.5V FAMILY DEVICES ................................... 48  
19.2 COP8 TOOLS OVERVIEW ................................................................................................................... 49  
19.3 WHERE TO GET TOOLS ..................................................................................................................... 50  
20.0 Revision History ....................................................................................................................................... 52  
21.0 Physical Dimensions ................................................................................................................................ 53  
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5.0 Connection Diagrams  
20091705  
Top View  
20 Pin Plastic SOIC WIDE Package  
See NS Package Number M20B  
20091702  
Top View  
44 Pin LLP Package  
See NS Package Number LQA44A  
20091704  
Top View  
28 Pin Plastic SOIC WIDE Package  
See NS Package Number M28B  
5
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Pinouts for 44-, 20- and 28-Pin Packages  
Port  
Type  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I
Alt. Function  
MIWU/SDA  
MIWU/SCL  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
INT  
44-Pin LLPa  
28-Pin SOICa  
20-Pin SOICa  
L0  
L1  
L2  
L3  
L4  
L5  
L6  
L7  
G0  
G1  
G2  
G3  
G4  
G5  
G6  
G7  
C0  
C1  
C2  
C3  
C4  
C5  
C6  
C7  
F0  
F1  
F2  
F3  
F4  
F5  
F6  
F7  
J0  
12  
13  
14  
15  
20  
21  
22  
23  
2
18  
19  
20  
21  
22  
23  
24  
25  
12  
11  
10  
9
12  
13  
14  
15  
16  
17  
18  
19  
10  
9
WDOUTa  
1
T1B  
44  
43  
32  
33  
34  
35  
37  
38  
39  
40  
16  
17  
18  
19  
4
8
T1A  
7
SO  
2
20  
1
SK  
3
SI  
4
2
I
CKO  
5
3
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
14  
15  
16  
17  
5
6
7
8
9
10  
11  
24  
25  
26  
27  
28  
29  
30  
31  
42  
41  
36  
3
26  
27  
28  
1
J1  
J2  
J3  
J4  
J5  
J6  
J7  
VCC  
8
7
6
5
GND  
CKI  
I
I
6
4
RESET  
13  
11  
a. G1 operation as WDOUT is controlled by Option Register, bit 2.  
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6
substantial amount of program memory space, designers  
can integrate additional features and functionality into the  
microcontroller program memory space. Also, the majority  
instructions executed by the device are single cycle, result-  
ing in minimum program execution time. In fact, 77% of the  
instructions are single byte single cycle, providing greater  
code and I/O efficiency, and faster code execution.  
6.0 Architectural Overview  
6.1 EMI REDUCTION  
The COP8TAB5/TAC5 devices incorporate circuitry that  
guards against electromagnetic interference - an increasing  
problem in today’s microcontroller board designs. National’s  
patented EMI reduction technology offers low EMI clock  
circuitry, gradual turn-on output drivers (GTOs) and internal  
Icc smoothing filters, to help circumvent many of the EMI  
issues influencing embedded control designs. National has  
achieved 15 dB–20 dB reduction in EMI transmissions when  
designs have incorporated its patented EMI reducing cir-  
cuitry.  
6.3.3 Many Single-Byte, Multi-Function Instructions  
The COP8 instruction set utilizes many single-byte, multi-  
function instructions. This enables a single instruction to  
accomplish multiple functions, such as DRSZ, DCOR, JID,  
LD (Load) and  
X (Exchange) instructions with post-  
incrementing and post-decrementing, to name just a few  
examples. In many cases, the instruction set can simulta-  
neously execute as many as three functions with the same  
single-byte instruction.  
6.2 ARCHITECTURE  
The COP8 family is based on a modified Harvard architec-  
ture, which allows data tables to be accessed directly from  
program memory. This is very important with modern  
microcontroller-based applications, since program memory  
is usually ROM or EPROM, while data memory is usually  
RAM. Consequently constant data tables need to be con-  
tained in non-volatile memory, so they are not lost when the  
microcontroller is powered down. In a modified Harvard ar-  
chitecture, instruction fetch and memory data transfers can  
be overlapped with a two stage pipeline, which allows the  
next instruction to be fetched from program memory while  
the current instruction is being executed using data memory.  
This is not possible with a Von Neumann single-address bus  
architecture.  
JID: (Jump Indirect); Single byte instruction decodes exter-  
nal events and jumps to corresponding service routines  
(analogous to “DO CASE” statements in higher level lan-  
guages).  
LAID: (Load Accumulator-Indirect); Single byte look up table  
instruction provides efficient data path from the program  
memory to the CPU. This instruction can be used for table  
lookup and to read the entire program memory for checksum  
calculations.  
RETSK: (Return Skip); Single byte instruction allows return  
from subroutine and skips next instruction. Decision to  
branch can be made in the subroutine itself, saving code.  
The COP8 family supports a software stack scheme that  
allows the user to incorporate many subroutine calls. This  
capability is important when using High Level Languages.  
With a hardware stack, the user is limited to a small fixed  
number of stack levels.  
AUTOINC/DEC: (Auto-Increment/Auto-Decrement); These  
instructions use the two memory pointers B and X to effi-  
ciently process a block of data (simplifying “FOR NEXT” or  
other loop structures in higher level languages).  
6.3.4 Bit-Level Control  
6.3 INSTRUCTION SET  
Bit-level control over many of the microcontroller’s I/O ports  
provides a flexible means to ease layout concerns and save  
board space. All members of the COP8 family provide the  
ability to set, reset and test any individual bit in the data  
memory address space, including memory-mapped I/O ports  
and associated registers.  
In today’s 8-bit microcontroller application arena cost/  
performance, flexibility and time to market are several of the  
key issues that system designers face in attempting to build  
well-engineered products that compete in the marketplace.  
Many of these issues can be addressed through the manner  
in which a microcontroller’s instruction set handles process-  
ing tasks. And that’s why the COP8 family offers a unique  
and code-efficient instruction set - one that provides the  
flexibility, functionality, reduced costs and faster time to mar-  
ket that today’s microcontroller based products require.  
6.3.5 Register Set  
Three memory-mapped pointers handle register indirect ad-  
dressing and software stack pointer functions. The memory  
data pointers allow the option of post-incrementing or post-  
decrementing with the data movement instructions (LOAD/  
EXCHANGE). And 15 memory-mapped registers allow de-  
signers to optimize the precise implementation of certain  
specific instructions.  
Code efficiency is important because it enables designers to  
pack more on-chip functionality into less program memory  
space (ROM, OTP or ROM). Selecting a microcontroller with  
less program memory size translates into lower system  
costs, and the added security of knowing that more code can  
be packed into the available program memory space.  
6.4 PACKAGING/PIN EFFICIENCY  
Real estate and board configuration considerations demand  
maximum space and pin efficiency, particularly given today’s  
high integration and small product form factors. Microcon-  
troller users try to avoid using large packages to get the I/O  
needed. Large packages take valuable board space and  
increase device cost, two trade-offs that microcontroller de-  
signs can ill afford.  
6.3.1 Key Instruction Set Features  
The COP8 family incorporates a unique combination of in-  
struction set features, which provide designers with optimum  
code efficiency and program memory utilization.  
6.3.2 Single Byte/Single Cycle Code Execution  
The efficiency is due to the fact that the majority of instruc-  
tions are of the single byte variety, resulting in minimum  
program space. Because compact code does not occupy a  
The COP8 family offers a wide range of packages and does  
not waste pins.  
7
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7.0 Absolute Maximum Ratings (Note  
Total Current into VCC Pin (Source)  
Total Current out of GND Pin  
(Sink)  
80 mA  
1)  
60 mA  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Storage Temperature Range  
−65˚C to +140˚C  
Note 1: Absolute maximum ratings indicate limits beyond which damage to  
the device may occur. DC and AC electrical specifications are not ensured  
when operating the device at absolute maximum ratings.  
Supply Voltage (VCC  
)
3.5V  
Voltage at Any Pin  
−0.3V to VCC +0.3V  
ESD Protection Level  
(Human Body Model)  
(Machine Model)  
2 kV  
200V  
8.0 Electrical Characteristics  
DC Electrical Characteristics −40˚C TA +85˚C unless otherwise  
specified.  
Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.  
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
Operating Voltage  
2.25  
2.75  
V
Power Supply Rise Time from 0.0V  
(On-Chip Power-On Reset Selected)  
Power Supply Ripple (Note 3)  
Supply Current (Note 4)  
20 µs  
10 ms  
Peak-to-Peak  
0.1 VCC  
V
CKI = 15 MHz  
VCC = 2.75V, tC = 0.65µs  
VCC = 2.75V, tC = 2.0 µs  
VCC = 2.75V, CKI = 0  
MHz  
6
mA  
mA  
CKI = 5MHz  
3.0  
HALT Current (Note 5) WATCHDOG Disabled  
<
TA = +25˚C  
2
15  
µA  
µA  
TA = +85˚C  
300  
IDLE Current (Note 4)  
CKI = 15 MHz  
VCC = 2.75V, tC = 0.65µs  
VCC = 2.75V, tC = 2.0 µs  
1
mA  
mA  
CKI = 5MHz  
0.8  
Input Levels (VIH, VIL)  
Logic High  
1.8V compatibility option  
selected and  
1.4  
V
L0 (SDA), L1 (SCL) and L2  
ACCESS.Bus is enabled  
All Other Inputs  
0.8 VCC  
0.3  
V
V
Logic Low  
0.25 VCC  
2.5  
Value of the Internal Bias Resistor  
for the Crystal/Resonator Oscillator  
Hi-Z Input Leakage (same as TRI-STATE output)  
Input Pullup Current  
1.0  
M  
VCC = 2.75V  
−0.1  
−15  
0.1  
+0.1  
µA  
µA  
V
VCC = 2.75V, VIN = 0V  
−120  
Port Input Hysteresis  
Output Current Levels  
Source (Weak Pull-Up)  
VCC = 2.25V, VOH = 1.7V  
VCC = 2.25V, VOH = 1.7V  
VCC = 2.25V, VOL = 0.4V  
−10  
−10  
10  
−80  
µA  
mA  
mA  
mA  
mA  
V
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
Allowable Sink & Source Current per Pin  
Maximum Input Current without Latchup  
RAM Retention Voltage, Vr  
Input Capacitance  
16  
200  
TBD  
8.5  
pF  
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8
8.0 Electrical Characteristics (Continued)  
AC Electrical Characteristics −40˚C TA +85˚C unless otherwise  
specified.  
Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.  
Parameter  
Instruction Cycle Time (tC)  
Conditions  
Min  
Typ  
Max  
Units  
Crystal/Resonator, External  
Internal R/C Oscillator  
R/C Oscillator Frequency Variation  
External CKI Clock Duty Cycle  
Rise Time  
2.25V VCC 2.75V  
2.25V VCC 2.75V  
2.25V VCC 2.75V  
fr = Max  
0.65  
DC  
µs  
µs  
%
1.0  
30  
55  
12  
8
45  
%
fr = 10 MHz Ext Clock  
fr = 10 MHz Ext Clock  
ns  
ns  
Fall Time  
Inputs  
MICROWIRE Setup Time (tUWS  
MICROWIRE Hold Time (tUWH  
)
20  
20  
ns  
ns  
ns  
)
MICROWIRE Output Propagation Delay (tUPD  
MICROWIRE Maximum Shift Clock  
Master Mode  
)
150  
750  
1.5  
kHz  
Slave Mode  
MHz  
Input Pulse Width  
Interrupt Input High Time (see (Note 2))  
Interrupt Input Low Time  
1
1
1
1
tC  
tC  
tC  
tC  
Timer Input High Time  
Timer Input Low Time  
ACCESS.Bus Input signals (see (Note 6))  
Bus Free Time Between Stop and Start Condition  
(tBUFi  
SCL Setup Time (tCSTOsi  
tSCLhigho  
)
)
Before Stop Condition  
After Start Condition  
Before Start Condition  
Before SCL Rising Edge  
(RE)  
8
8
8
2
mclk  
mclk  
mclk  
mclk  
SCL Hold Time (tCSTRhi  
)
SCL Setup Time (tCSTRsi  
)
Data High Setup Time (tDHCsi  
)
Data Low Setup Time (tDLCsi  
SCL Low Time (tSCLlowi  
SCL High Time (tSCLhighi  
SDA Hold Time (tSDAhi  
SDA Setup Time (tSDAsi  
)
Before SCL RE  
2
12  
12  
0
mclk  
mclk  
mclk  
ns  
)
After SCL Falling Edge (FE)  
After SCL RE  
)
)
After SCL FE  
)
Before SCL RE  
2
mclk  
ACCESS.Bus Output Signals (see(Note 6))  
Bus Free Time Between Stop and Start Condition  
tSCLhigho  
(tBUFo  
)
SCL Setup Time (tCSTOso  
)
)
Before Stop Condition  
After Start Condition  
Before Start Condition  
Before SCL RE  
Before SCL RE  
After SCL FE  
tSCLhigho  
tSCLhigho  
tSCLhigho  
tSCLhigho  
tSCLhigho  
16  
SCL Hold Time (tCSTRho  
)
SCL Setup Time (tCSTRso  
Data High Setup Time (tDHCso  
Data Low Setup Time (tDLCso  
SCL Low Time (tSCLlowo  
SCL High Time (tSCLhigho  
SDA Hold Time (tSDAho  
SDA Valid Time (tSDAso  
)
)
mclk  
mclk  
mclk  
mclk  
)
After SCL RE  
16  
)
After SCL FE  
7
)
Before SCL FE  
7
Note 2: t = Instruction cycle time (Clock input frequency divided by 10).  
C
<
Note 3: Maximum rate of voltage change must be 0.5 V/ms.  
9
www.national.com  
8.0 Electrical Characteristics (Continued)  
AC Electrical Characteristics −40˚C TA +85˚C unless otherwise  
specified. (Continued)  
Note 4: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, inputs connected to V and outputs driven low but not connected  
CC  
to a load.  
Note 5: The HALT mode will stop CKI from oscillating in the R/C and the Crystal configurations. CKI is TRI-STATE. Measurement of I HALT is done with device  
DD  
neither sourcing nor sinking current; with L. F, C, J, G0 and G2–G5 programmed as low outputs and not driving a load; all outputs programmed low and not driving  
a load; all inputs tied to V ; WATCHDOG and clock monitor disabled. Parameter refers to HALT mode entered via setting bit 7 of the G Port data register.  
CC  
2
Note 6: The ACCESS.Bus interface of the COP8TAB5/TAC5 device implements and meets the timings necessary for interface to the I C and SMBus protocols at  
logic levels. The bus drivers are designed with open-drain outputs, as required for proper bidirectional operation. The device will not meet the AC timing and  
current/voltage drive requirements of the full bus specifications.  
20091782  
FIGURE 1. MICROWIRE/PLUS Timing  
20091783  
FIGURE 2. ACB Start and Stop Condition Timing  
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10  
8.0 Electrical Characteristics (Continued)  
20091784  
FIGURE 3. ACB Start Condition Timing  
20091785  
FIGURE 4. ACB Data Timing  
speakers. This flexibility helps to ensure a cleaner design,  
with fewer external components and lower costs. Below is  
the general description of all available pins.  
9.0 Pin Descriptions  
The COP8TAB5/TAC5 I/O structure enables designers to  
reconfigure the microcontroller’s I/O functions with a single  
instruction. Each individual I/O pin can be independently  
configured as output pin low, output high, input with high  
impedance or input with weak pull-up device. A typical ex-  
ample is the use of I/O pins as the keyboard matrix input  
lines. The input lines can be programmed with internal weak  
pull-ups so that the input lines read logic high when the keys  
are all open. With a key closure, the corresponding input line  
will read a logic zero since the weak pull-up can easily be  
overdriven. When the key is released, the internal weak  
pull-up will pull the input line back to logic high. This elimi-  
nates the need for external pull-up resistors. The high cur-  
rent options are available for driving LEDs, motors and  
VCC and GND are the power supply pins.  
Users of the LLP package are cautioned to be aware that the  
central metal area and the pin 1 index mark on the bottom of  
the package may be connected to GND. See figure below:  
11  
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C1 Multi-Input Wake-Up  
C0 Multi-Input Wake-Up  
9.0 Pin Descriptions (Continued)  
Port G is an 8-bit port. Pin G0, G2–G5 are bi-directional I/O  
ports. Pin G6 is always a general purpose Hi-Z input. All pins  
have Schmitt Triggers on their inputs. Pin G1 serves as the  
dedicated WATCHDOG output with weak pull-up if the  
WATCHDOG feature is selected by the Option register.  
The pin is a general purpose I/O if WATCHDOG feature is  
not selected. If WATCHDOG feature is selected, bit 1 of the  
Port G configuration and data register does not have any  
effect on Pin G1 setup. Pin G7 is either input or output  
depending on the oscillator option selected. With the crystal  
oscillator option selected, G7 serves as the dedicated output  
pin for the CKO clock output. With the internal R/C or the  
external oscillator option selected, G7 serves as a general  
purpose Hi-Z input pin and is also used to bring the device  
out of HALT mode with a low to high transition on G7.  
Since G6 is an input only pin and G7 is the dedicated CKO  
clock output pin (crystal clock option) or general purpose  
input (R/C or external clock option), the associated bits in the  
data and configuration registers for G6 and G7 are used for  
special purpose functions as outlined below. Reading the G6  
and G7 data bits will return zeros.  
20091720  
FIGURE 5. LLP Package Bottom View  
The device will be placed in the HALT mode by writing a “1”  
to bit 7 of the Port G Data Register. Similarly the device will  
be placed in the IDLE mode by writing a “1” to bit 6 of the  
Port G Data Register.  
CKI is the clock input. This pin can be connected (in con-  
junction with CKO) to an external crystal circuit to form a  
crystal oscillator, to an external resistor for RC oscillator  
operation or to an external clock. See Oscillator Description  
section.  
Writing a “1” to bit 6 of the Port G Configuration Register  
enables the MICROWIRE/PLUS to operate with the alter-  
nate phase of the SK clock. The G7 configuration bit, if set  
high, enables the clock start up delay after HALT when the  
R/C clock configuration is used.  
RESET is the master reset input. See Reset description  
section.  
The device contains up to five bidirectional 8-bit I/O ports (C,  
F, G, J and L), where each individual bit may be indepen-  
dently configured as an input (Schmitt trigger inputs on all  
ports), output or TRI-STATE under program control. Three  
data memory address locations are allocated for each of  
these I/O ports. Each I/O port has three associated 8-bit  
memory mapped registers, the CONFIGURATION register,  
the output DATA register and the Pin input register. (See the  
memory map for the various addresses associated with the  
I/O ports.) Figure 6 shows the I/O port configurations. The  
DATA and CONFIGURATION registers allow for each port bit  
to be individually configured under software control as  
shown below:  
Config. Reg.  
CLKDLY  
Alternate SK  
Data Reg.  
HALT  
IDLE  
G7  
G6  
Port G has the following alternate features:  
G7 CKO Oscillator dedicated output or general purpose  
input.  
G6 SI (MICROWIRE/PLUS Serial Data Input)  
G5 SK (MICROWIRE/PLUS Serial Clock)  
G4 SO (MICROWIRE/PLUS Serial Data Output)  
G3 T1A (Timer T1 I/O)  
CONFIGURATION  
Register  
DATA  
Port Set-Up  
Hi-Z Input  
Register  
G2 T1B (Timer T1 Capture Input)  
0
0
G1 WDOUT WATCHDOG and/or Clock Monitor if WATCH-  
DOG enabled, otherwise it is a general purpose I/O  
(TRI-STATE Output)  
Input with Weak Pull-Up  
Push-Pull Zero Output  
Push-Pull One Output  
0
1
1
1
0
1
G0 INTR (External Interrupt Input)  
Port J is an 8-bit I/O port. All J pins have Schmitt triggers on  
the inputs. At RESET, Port J outputs are enabled and are  
forced to the High state.  
Port C supports the Multi-Input Wake-Up feature on all eight  
pins. Port C is not available on 20 and 28 pin packages. The  
user should ensure that Port C Multi-Input Wake-Up is dis-  
abled by clearing the CWKEN Register. Port C has the  
following alternate pin functions:  
Port L is an 8-bit I/O port. All L-pins have Schmitt triggers on  
the inputs.  
Pins L0 (SDA), L1 (SCL) and L2 inputs provide compatibility  
with 1.8V logic levels when LVCMP (Option Register bit 7) is  
set and the ACCESS.Bus is enabled.  
C7 Multi-Input Wake-Up  
C6 Multi-Input Wake-Up  
C5 Multi-Input Wake-Up  
C4 Multi-Input Wake-Up  
C3 Multi-Input Wake-Up  
C2 Multi-Input Wake-Up  
Port L supports the Multi-Input Wake-Up feature on all eight  
pins. Port L has the following alternate pin functions:  
L7 Multi-Input Wake-Up  
L6 Multi-Input Wake-Up  
L5 Multi-Input Wake-Up  
L4 Multi-Input Wake-Up  
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12  
9.0 Pin Descriptions (Continued)  
L3 Multi-Input Wake-Up  
10.0 Functional Description  
The architecture of the device is a modified Harvard archi-  
tecture. With the Harvard architecture, the program memory  
(ROM) is separate from the data store memory (RAM). Both  
Program Memory and Data Memory have their own separate  
addressing space with separate address buses. The archi-  
tecture, though based on the Harvard architecture, permits  
transfer of data from ROM Memory to RAM.  
L2 Multi-Input Wake-Up (optional 1.8V compatible input)  
L1 Multi-Input Wake-Up or ACCESS.Bus Serial Clock (op-  
tional 1.8V compatible input)  
L0 Multi-Input Wake-Up or ACCESS.Bus Serial Data (op-  
tional 1.8V compatible input)  
10.1 CPU REGISTERS  
The CPU can do an 8-bit addition, subtraction, logical or shift  
operation in one instruction (tC) cycle time.  
20091760  
FIGURE 6. I/O Port Configurations  
20091761  
FIGURE 7. I/O Port ConfigurationsOutput Mode  
20091762  
FIGURE 8. I/O Port ConfigurationsInput Mode  
13  
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10.2 PROGRAM MEMORY  
10.0 Functional Description  
The program memory consists of 4096 bytes of ROM  
Memory. These bytes may hold program instructions or con-  
stant data (data tables for the LAID instruction, jump vectors  
for the JID instruction, and interrupt vectors for the VIS  
instruction). The program memory is addressed by the 15-bit  
program counter (PC). All interrupts in the device vector to  
program memory location 00FF Hex. The program memory  
reads 00 Hex in the erased state. Program execution starts  
at location 0 after RESET.  
(Continued)  
There are five CPU registers:  
A is the 8-bit Accumulator Register  
PC is the 15-bit Program Counter Register  
PU is the upper 7 bits of the program counter (PC)  
PL is the lower 8 bits of the program counter (PC)  
B is an 8-bit RAM address pointer, which can be optionally  
post auto incremented or decremented.  
If a Return instruction is executed when the SP contains 6F  
(hex), instruction execution will continue from Program  
Memory location 7FFF (hex). If location 7FFF is accessed by  
an instruction fetch, the ROM Memory will return a value of  
00. This is the opcode for the INTR instruction and will cause  
a Software Trap.  
X is an 8-bit alternate RAM address pointer, which can be  
optionally post auto incremented or decremented.  
SP is the 8-bit stack pointer, which points to the subroutine/  
interrupt stack (in RAM). With reset the SP is initialized to  
RAM address 06F Hex. The SP is decremented as items are  
pushed onto the stack. SP points to the next available loca-  
tion on the stack.  
All the CPU registers are memory mapped with the excep-  
tion of the Accumulator (A) and the Program Counter (PC).  
TABLE 1. Available Memory Address Ranges  
Program Memory Option Register Data Memory  
Address (Hex) Size (RAM)  
Segments  
Available  
Maximum RAM  
Address (HEX)  
Device  
Size (ROM)  
2048  
COP8TAB5  
COP8TAC5  
0x07FF (hex)  
0x0FFF (hex)  
128  
Segment 0  
067F  
4096  
Bit 6  
Bit 5  
This bit defines the most significant bit of the os-  
cillaor selection. (See Section 10.6 OSCILLATOR  
CIRCUITS) for more information on Oscillator  
selection.)  
10.3 DATA MEMORY  
The data memory address space includes the on-chip RAM  
and data registers, the I/O registers (Configuration, Data and  
Pin), the control registers, the MICROWIRE/PLUS SIO shift  
register, ACCESS.Bus Interface and the various registers  
and counters associated with the timer, T1. Data memory is  
addressed directly by the instruction or indirectly by the B, X  
and SP pointers.  
This bit is provided for program code compatibility  
with Flash based devices and can be either one or  
zero. The value is ignored in the device. Security  
os not required in this device, since the ROM  
contained in this device CANNOT be read using  
programmers that are capable of reading the com-  
patible Flash based device.  
The data memory consists of 128 bytes of RAM. Sixteen  
bytes of RAM are mapped as “registers” at addresses 0F0 to  
0FF Hex. These registers can be loaded immediately, and  
also decremented and tested with the DRSZ (decrement  
register and skip if zero) instruction. The memory pointer  
registers X, SP and B are memory mapped into this space at  
address locations 0FC to 0FE Hex respectively, with the  
other registers being available for general usage.  
Bits 4, 3 These bits define the two least significant bits of  
the oscillator selection.  
Bit 2  
= 1  
WATCHDOG feature disabled. G1 is a general  
purpose I/O.  
The instruction set permits any bit in memory to be set, reset  
or tested. All I/O and registers (except A and PC) are  
memory mapped; therefore, I/O bits and register bits can be  
directly and individually set, reset and tested. The accumu-  
lator (A) bits can also be directly and individually tested.  
= 0  
WATCHDOG feature enabled. G1 pin is  
WATCHDOG output with weak pullup.  
Bit 1  
= 1  
= 0  
HALT mode disabled.  
HALT mode enabled.  
Note: RAM contents are undefined upon power-up.  
10.4 OPTION REGISTER  
Bit 0  
The Option Register, located at address 0x0FFF (hex) in the  
ROM Program Memory, is used to configure the user select-  
able WATCHDOG, HALT and Oscillator selection options.  
The register is defined at the same time as the program  
memory as a part of the ROM code and cannot be changed.  
This bit is provided for program code compatibility  
with Flash based devices and can be either one or  
zero. The value is ignored in the device since the  
Boot ROM does not exist. Execution following RE-  
SET will always be from the Program Memory.  
The format of the Option register is as follows:  
The COP8 assembler defines a special ROM section type,  
CONF, into which the Option Register data may be coded.  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
WATCH  
DOG  
The following examples illustrate the declaration of the Op-  
tion Register.  
LVCMP CLKSEL2 RSVD CLKSEL1 CLKSEL0  
HALT FLEX  
Syntax:  
Bit 7  
When this bit is set and the ACCESS.Bus is en-  
abled, inputs L0, L1 and L2, are compatible with  
1.8V logic levels.  
[label:].sect  
.db  
config, conf  
value ;1 byte,  
www.national.com  
14  
WATCHDOG (if enabled):  
10.0 Functional Description  
The device comes out of reset with both the WATCHDOG  
logic and the Clock Monitor detector armed, with the  
WATCHDOG service window bits set and the Clock Moni-  
tor bit set. The WATCHDOG and Clock Monitor circuits  
are inhibited during reset. The WATCHDOG service win-  
dow bits being initialized high default to the maximum  
WATCHDOG service window of 64k T0 clock cycles. The  
Clock Monitor bit being initialized high will cause a Clock  
Monitor error following reset if the clock has not reached  
the minimum specified frequency at the termination of  
reset. A Clock Monitor error will cause an active low error  
output on pin G1. This error output will continue until  
16–32 T0 clock cycles following the clock frequency  
reaching the minimum specified value, at which time the  
G1 output will go high.  
(Continued)  
;configures  
;options  
.endsect  
Example: The following sets a value in the Option Register  
and User Identification for a COP8TAC9HLQ7. The Option  
Register bit values shown select options: Security disabled,  
WATCHDOG enabled HALT mode enabled and execution  
will commence from ROM Memory.  
.chip  
.sect  
.db  
8TAC  
option, conf  
0x01  
;wd, halt, flex  
.endsect  
...  
.end  
start  
10.5.1 External Reset  
The RESET input, when pulled low, initializes the device.  
The RESET pin must be held low for a minimum of one  
instruction cycle to guarantee a valid reset. An R/C circuit on  
the RESET pin with a delay 5 times (5x) greater than the  
power supply rise time is recommended. Reset should also  
be wide enough to ensure crystal start-up upon Power-Up.  
10.5 RESET  
The device is initialized when the RESET pin is pulled low or  
the On-chip Power-On Reset is activated.  
RESET may also be used to cause an exit from the HALT  
mode.  
A recommended reset circuit for this device is shown in  
Figure 10.  
20091721  
FIGURE 9. Reset Logic  
The following occurs upon initialization:  
Port A: TRI-STATE (High Impedance Input)  
Port B: TRI-STATE (High Impedance Input)  
Port G: TRI-STATE (High Impedance Input). Exceptions: If  
Watchdog is enabled, then G1 is Watchdog output. G0  
and G2 have their weak pull-up enabled during RESET.  
20091722  
Port J: Output High  
Port L: TRI-STATE (High Impedance Input)  
PC: CLEARED to 0000  
FIGURE 10. Reset Circuit Using External Reset  
PSW, CNTRL and ICNTRL registers: CLEARED  
SIOR:  
10.5.2 On-Chip Power-On Reset  
The device generates an internal reset as VCC rises to a  
voltage level above 2.0V. The on-chip reset circuitry is able  
to detect both fast and slow rise times on VCC (VCC rise time  
between 20 µs and 10 ms).  
UNAFFECTED after RESET with power already applied  
RANDOM after RESET at power-on  
ITMR, CLKPS: Cleared  
Accumulator and Timer 1:  
Under no circumstances should the RESET pin be allowed  
to float. If the on-chip Power-On Reset feature is being used,  
RESET pin should be connected to VCC , either directly or  
through a pull-up resistor. The output of the power-on reset  
detector will always preset the Idle timer to 00FF(256 tC). At  
this time, the internal reset will be generated.  
RANDOM after RESET  
CWKEN, CWKEDG, LWKEN, LWKEDG: CLEARED  
CWKPND, LWKPND: RANDOM  
SP (Stack Pointer):  
Initialized to RAM address 06F Hex  
B and X Pointers:  
The internal reset will not be turned off until the Idle timer  
underflows. The internal reset will perform the same func-  
tions as external reset. The user is responsible for ensuring  
that VCC is at the minimum level for operating within the 256  
tC. After the underflow, the logic is designed such that the  
Power On Reset circuit will generate no additional internal  
resets as long as VCC remains above 2.0V.  
UNAFFECTED after RESET with power already applied  
RANDOM after RESET at power-on  
RAM:  
UNAFFECTED after RESET with power already applied  
RANDOM after RESET at power-on  
Note: While the POR feature of the COP8TAB5/TAC5 was never intended to  
function as a brownout detector, there are certain constraints of this  
15  
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10.6.1 Crystal Oscillator  
10.0 Functional Description  
The crystal Oscillator mode can be selected by programming  
Option Bit 4 to 1. CKI is the clock input while G7/CKO is the  
clock generator output to the crystal. An on-chip bias resistor  
connected between CKI and CKO can be enabled by pro-  
gramming Option Byte Bit 3 to 1 with the crystal oscillator  
option selection. The value of the resistor is in the range of  
0.3M to 2.5M (typically 1.0M). Table 3 shows the component  
values required for various standard crystal values. Resistor  
R2 is only used when the on-chip bias resistor is disabled.  
Figure 12 shows the crystal oscillator connection diagram.  
(Continued)  
block that the system designer must address to properly recover from  
a brownout condition. This is true regardless of whether the internal  
POR or the external reset feature is used.  
A brownout condition is reached when V  
of the device goes below  
CC  
the minimum operating conditions of the device. The minimum guar-  
anteed operating conditions are defined in the Electrical Specifica-  
tions.  
When using either the external reset or the POR feature to recover  
from a brownout condition, external reset must be applied whenever  
V
goes below the minimum operating conditions as stated above.  
CC  
The contents of data registers and RAM are unknown fol-  
lowing the on-chip reset.  
TABLE 3. Crystal Oscillator Configuration,  
TA = 25˚C, VCC = 2.5V  
R1 (k) R2 (M) C1 (pF) C2 (pF) CKI Freq. (MHz)  
0
0
1
1
1
1
18  
18  
45  
18  
18  
15  
10  
0
30–36  
4
5.6  
100 100–156  
0.455  
10.6.2 R/C Oscillator  
The device features an R/C oscillator with two modes of  
operation:  
1. 1. R/C with internal R operaing at a fixed frequency (R/C  
mode)  
2. 2. R/C with external frequency control resistor (R/C+R  
mode).  
If the Oscillator Selection bits of the Option Byte remain  
unprogrammed (equal to zero), the R/C Oscillator mode will  
be selected. In R/C oscillation mode, CKI is left floating,  
while G7/CKO is available as a general purpose input G7  
and/or HALT control. The R/C controlled oscillator has on-  
chip resistor and capacitor for maximum R/C oscillator fre-  
quency operation. The maximum frequency is 10 MHz  
20% for temperature range of −40˚C to +85˚C.  
The R/C Oscillator with external frequency control resistor  
mode (R/C+R) can be selected by programming Option Byte  
Bit 3 to 1 and Option Byte Bits 6 and 4 to 0. In R/C+R  
oscillation mode, the frequency of oscillation is controlled by  
the voltage across a resistor connected from the CKI pin to  
GND. G7/CKO is available as a general purpose input G7  
and/or HALT control. The maximum frequency is 10 MHz  
20% for temperature range of −40˚C to +85˚C. For lower  
frequencies, an external resistor should be connected be-  
tween CKI and GND. PC board trace length on the CKI pin  
should be kept as short as possible.  
20091723  
FIGURE 11. Reset Timing (Power-On Reset Enabled)  
with VCC Tied to RESET  
10.6 OSCILLATOR CIRCUITS  
There are five clock oscillator options available: Crystal Os-  
cillator with or without on-chip bias resistor, fully internal R/C  
Oscillator, R/C Oscillator with external frequency determina-  
tion resistor and External Oscillator. The oscillator feature is  
selected by programming the Option Byte, which is summa-  
rized in Table 2.  
Table 4 shows the oscillator frequency as a function of  
approximate external resistance on the CKI pin. Figure 14  
shows the R/C oscillator configuration.  
TABLE 4. R/C Oscillator Configuration,  
−40˚C to +85˚C,  
TABLE 2. Oscillator Option  
OSC Freq. Variation of 20%  
Option Option Option  
Byte 6 Byte 4 Byte 3  
Oscillator Option  
External Resistor  
R/C OSC Freq  
Instr. Cycle  
(µs)  
(k)  
56  
(MHz)  
0
0
0
0
0
1
0
1
0
On-Chip R/C Oscillator  
R/C Oscillator with External Resistor  
15  
10  
5
0.65  
Crystal Oscillator without Bias  
Resistor  
87  
1.0  
200  
500  
2.0  
0
1
1
x
1
x
Crystal Oscillator with Bias Resistor  
External Oscillator  
2
5.0  
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16  
10.0 Functional Description (Continued)  
With On-Chip Bias Resistor  
With External Bias Resistor  
20091724  
20091725  
FIGURE 12. Crystal Oscillator  
20091726  
FIGURE 13. External Oscillator  
With External Frequency Control Resistor (R/C+R)  
With Fully On-Chip R/C Oscillator.  
20091727  
20091728  
FIGURE 14. R/C Oscillator  
10.6.3 External Oscillator  
CLKPS register, the user can divide the input oscillator clock  
by an integer multiple (1256) and reduce the CPU clock  
frequency. The format of the CLKPS Register is shown in  
Table 5. The value written to the CLKPS register is one less  
than the desired divider. A value of 0 (zero) written to the  
CLKPS register yields a CPU clock equal to the input clock  
frequency. A value of 255 written to the CLKPS register  
yields a CPU clock with a period equal to 256 input clock  
periods.  
The External Oscillator mode can be selected by program-  
ming Option Bit 3 to 0 and Option Bit 4 to 0. CKI can be  
driven by an external clock signal provided it meets the  
specified duty cycle, rise and fall times, and input levels.  
G7/CKO is available as a general purpose input G7 and/or  
Halt control. Figure 13 shows the external oscillator connec-  
tion diagram.  
10.6.4 Clock Prescaler  
The device is equipped with a programmable clock prescaler  
which allows the user to dynamically adjust the clock speed,  
and thus the power dissipation, to the processing needs of  
the application. By merely writing an eight-bit value to the  
TABLE 5. Clock Prescale Register (CLKPS)  
CLKPS  
Bit 7  
Bit 0  
17  
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T1ENB Timer T1 Interrupt Enable for T1B Input capture  
edge  
10.0 Functional Description  
(Continued)  
10.7.4 ITMR Register (Address X'00CF)  
10.7 CONTROL REGISTERS  
RSVD  
ITSEL2  
ITSEL1 ITSEL0  
Bit 0  
10.7.1 CNTRL Register (Address X'00EE)  
Bit 7  
T1C3  
Bit 7  
T1C2  
T1C1  
T1C0  
MSEL  
IEDG  
SL1  
SL0  
Bit 0  
The ITMR register contains the following bits:  
RSVD These bits are reserved and must be 0.  
ITSEL2 Idle Timer period select bit.  
ITSEL1 Idle Timer period select bit.  
ITSEL0 Idle Timer period select bit.  
The Timer1 (T1) and MICROWIRE/PLUS control register  
contains the following bits:  
T1C3  
T1C2  
T1C1  
T1C0  
Timer T1 mode control bit  
Timer T1 mode control bit  
Timer T1 mode control bit  
11.0 Timers  
The device contains a very versatile set of timers (T0 and  
T1). Timer T1 and associated autoreload/capture registers  
power up containing random data.  
Timer T1 Start/Stop control in timer  
modes 1 and 2. T1 Underflow Interrupt  
Pending Flag in timer mode 3  
MSEL  
IEDG  
Selects G5 and G4 as MICROWIRE/PLUS  
signals SK and SO respectively  
11.1 TIMER T0 (IDLE TIMER)  
External interrupt edge polarity select  
(0 = Rising edge, 1 = Falling edge)  
The device supports applications that require maintaining  
real time and low power with the IDLE mode. This IDLE  
mode support is furnished by the IDLE Timer T0, which is a  
16-bit timer. The user cannot read or write to the IDLE Timer  
T0, which is a count down timer.  
SL1 & SL0 Select the MICROWIRE/PLUS clock divide  
by (00 = 2, 01 = 4, 1x = 8)  
10.7.2 PSW Register (Address X'00EF)  
The clock to the IDLE Timer is the instruction cycle clock  
(one-tenth of the CKI frequency).  
HC  
C
T1PNDA  
T1ENA  
EXPND  
BUSY  
EXEN  
GIE  
In addition to its time base function, the Timer T0 supports  
the following functions:  
Bit 7  
Bit 0  
The PSW register contains the following select bits:  
Exit out of the Idle Mode (See Idle Mode description)  
WATCHDOG logic (See WATCHDOG description)  
Start up delay out of the HALT mode  
HC  
C
Half Carry Flag  
Carry Flag  
T1PNDA Timer T1 Interrupt Pending Flag (Autoreload RA  
in mode 1, T1 Underflow in Mode 2, T1A capture  
edge in mode 3)  
Start up delay from POR  
is a functional block diagram showing the structure of the  
IDLE Timer and its associated interrupt logic.  
T1ENA Timer T1 Interrupt Enable for Timer Underflow  
or T1A Input capture edge  
Bits 11 through 15 of the ITMR register can be selected for  
triggering the IDLE Timer interrupt. Each time the selected  
bit underflows (every 4k, 8k, 16k, 32k or 64k selected  
clocks), the IDLE Timer interrupt pending bit T0PND is set,  
thus generating an interrupt (if enabled), and bit 6 of the Port  
G data register is reset, thus causing an exit from the IDLE  
mode if the device is in that mode.  
EXPND External interrupt pending  
BUSY  
EXEN  
GIE  
MICROWIRE/PLUS busy shifting flag  
Enable external interrupt  
Global interrupt enable (enables interrupts)  
The Half-Carry flag is also affected by all the instructions that  
affect the Carry flag. The SC (Set Carry) and RC (Reset  
Carry) instructions will respectively set or clear both the carry  
flags. In addition to the SC and RC instructions, ADC, SUBC,  
RRC and RLC instructions affect the Carry and Half Carry  
flags.  
In order for an interrupt to be generated, the IDLE Timer  
interrupt enable bit T0EN must be set, and the GIE (Global  
Interrupt Enable) bit must also be set. The T0PND flag and  
T0EN bit are bits 5 and 4 of the ICNTRL register, respec-  
tively. The interrupt can be used for any purpose. Typically, it  
is used to perform a task upon exit from the IDLE mode. For  
more information on the IDLE mode, refer to Section 12.2  
IDLE MODE.  
10.7.3 ICNTRL Register (Address X'00E8)  
Unused LPEN  
Bit 7  
T0PND  
T0EN µWPND µWEN T1PNDB  
T1ENB  
Bit 0  
The Idle Timer period is selected by bits 0–2 of the ITMR  
register Bit 3 of the ITMR Register is reserved and should  
not be used as a software flag. Bits 4 through 7 of the ITMR  
Register are reserved and must be zero.  
The ICNTRL register contains the following bits:  
LPEN  
L/C Port Interrupt Enable (Multi-Input  
Wake-Up/Interrupt)  
TABLE 6. Idle Timer Window Length  
T0PND Timer T0 Interrupt pending  
ITSEL2  
ITSEL1  
ITSEL0  
Idle Timer Period  
4,096 inst. cycles  
8,192 inst. cycles  
16,384 inst. cycles  
32,768 inst. cycles  
65,536 inst. cycles  
T0EN  
Timer T0 Interrupt Enable (Bit 12 toggle)  
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
µWPND MICROWIRE/PLUS interrupt pending  
µWEN  
Enable MICROWIRE/PLUS interrupt  
T1PNDB Timer T1 Interrupt Pending Flag for T1B capture  
edge  
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18  
In this mode, the timer T1 counts down at a fixed rate of tC.  
Upon every underflow the timer is alternately reloaded with  
the contents of supporting registers, R1A and R1B. The very  
first underflow of the timer causes the timer to reload from  
the register R1A. Subsequent underflows cause the timer to  
be reloaded from the registers alternately beginning with the  
register R1B.  
11.0 Timers (Continued)  
TABLE 6. Idle Timer Window Length (Continued)  
ITSEL2  
ITSEL1  
ITSEL0  
Idle Timer Period  
Reserved - Undefined  
Reserved - Undefined  
Reserved - Undefined  
1
1
1
0
1
1
1
0
1
The T1 Timer control bits, T1C3, T1C2 and T1C1 set up the  
timer for PWM mode operation.  
The ITSEL bits of the ITMR register are cleared on Reset  
and the Idle Timer period is reset to 4,096 instruction cycles.  
Figure 15 shows a block diagram of the timer in PWM mode.  
The underflows can be programmed to toggle the T1A output  
pin. The underflows can also be programmed to generate  
interrupts.  
11.1.1 ITMR Register  
RSVD  
ITSEL2 ITSEL1 ITSEL0  
Bit 2 Bit 1 Bit 0  
Underflows from the timer are alternately latched into two  
pending flags, T1PNDA and T1PNDB. The user must reset  
these pending flags under software control. Two control  
enable flags, T1ENA and T1ENB, allow the interrupts from  
the timer underflow to be enabled or disabled. Setting the  
timer enable flag T1ENA will cause an interrupt when a timer  
underflow causes the R1A register to be reloaded into the  
timer. Setting the timer enable flag T1ENB will cause an  
interrupt when a timer underflow causes the R1B register to  
be reloaded into the timer. Resetting the timer enable flags  
will disable the associated interrupts.  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
RSVD: These bits are reserved and must be set to 0.  
ITSEL2:0: Selects the Idle Timer period as described in  
Table 6  
Any time the IDLE Timer period is changed there is the  
possibility of generating a spurious IDLE Timer interrupt by  
setting the T0PND bit. The user is advised to disable IDLE  
Timer interrupts prior to changing the value of the ITSEL bits  
of the ITMR Register and then clear the T0PND bit before  
attempting to synchronize operation to the IDLE Timer.  
Either or both of the timer underflow interrupts may be  
enabled. This gives the user the flexibility of interrupting  
once per PWM period on either the rising or falling edge of  
the PWM output. Alternatively, the user may choose to inter-  
rupt on both edges of the PWM output.  
11.2 TIMER T1  
One of the main functions of a microcontroller is to provide  
timing and counting capability for real-time control tasks. The  
COP8 family offers a very versatile 16-bit timer/counter  
structure, and two supporting 16-bit autoreload/capture reg-  
isters (R1A and R1B), optimized to reduce software burdens  
in real-time control applications. The timer block has two pins  
associated with it, T1A and T1B. Pin T1A supports I/O re-  
quired by the timer block, while pin T1B is an input to the  
timer block.  
The timer block has three operating modes: Processor Inde-  
pendent PWM mode, External Event Counter mode, and  
Input Capture mode.  
The control bits T1C3, T1C2, and T1C1 allow selection of the  
different modes of operation.  
11.3 MODE 1. PROCESSOR INDEPENDENT PWM  
MODE  
One of the timer’s operating modes is the Processor Inde-  
pendent PWM mode. In this mode, the timer generates a  
“Processor Independent” PWM signal because once the  
timer is setup, no more action is required from the CPU  
which translates to less software overhead and greater  
throughput. The user software services the timer block only  
when the PWM parameters require updating. This capability  
is provided by the fact that the timer has two separate 16-bit  
reload registers. One of the reload registers contains the  
“ON” timer while the other holds the “OFF” time. By contrast,  
a microcontroller that has only a single reload register re-  
quires an additional software to update the reload value  
(alternate between the on-time/off-time).  
20091731  
FIGURE 15. Timer in PWM Mode  
11.4 MODE 2. EXTERNAL EVENT COUNTER MODE  
This mode is quite similar to the processor independent  
PWM mode described above. The main difference is that the  
timer, T1, is clocked by the input signal from the T1A pin. The  
T1 timer control bits, T1C3, T1C2 and T1C1 allow the timer  
to be clocked either on a positive or negative edge from the  
T1A pin. Underflows from the timer are latched into the  
T1PNDA pending flag. Setting the T1ENA control flag will  
cause an interrupt when the timer underflows.  
The timer can generate the PWM output with the width and  
duty cycle controlled by the values stored in the reload  
registers. The reload registers control the countdown values  
and the reload values are automatically written into the timer  
when it counts down through 0, generating interrupt on each  
reload. Under software control and with minimal overhead,  
the PMW outputs are useful in controlling motors, triacs, the  
intensity of displays, and in providing inputs for data acqui-  
sition and sine wave generators.  
In this mode the input pin T1B can be used as an indepen-  
dent positive edge sensitive interrupt input if the T1ENB  
control flag is set. The occurrence of a positive edge on the  
T1B input pin is latched into the T1PNDB flag.  
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11.0 Timers (Continued)  
Figure 16 shows a block diagram of the timer in External  
Event Counter mode.  
Note: The PWM output is not available in this mode since the T1A pin is  
being used as the counter input clock.  
20091732  
FIGURE 16. Timer in External Event Counter Mode  
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20  
Underflows from the timer can also be programmed to gen-  
erate interrupts. Underflows are latched into the timer T1C0  
pending flag (the T1C0 control bit serves as the timer under-  
flow interrupt pending flag in the Input Capture mode). Con-  
sequently, the T1C0 control bit should be reset when enter-  
ing the Input Capture mode. The timer underflow interrupt is  
enabled with the T1ENA control flag. When a T1A interrupt  
occurs in the Input Capture mode, the user must check both  
the T1PNDA and T1C0 pending flags in order to determine  
whether a T1A input capture or a timer underflow (or both)  
caused the interrupt.  
11.0 Timers (Continued)  
11.5 MODE 3. INPUT CAPTURE MODE  
The device can precisely measure external frequencies or  
time external events by placing the timer block, T1, in the  
input capture mode. In this mode, the reload registers serve  
as independent capture registers, capturing the contents of  
the timer when an external event occurs (transition on the  
timer input pin). The capture registers can be read while  
maintaining count, a feature that lets the user measure  
elapsed time and time between events. By saving the timer  
value when the external event occurs, the time of the exter-  
nal event is recorded. Most microcontrollers have a latency  
time because they cannot determine the timer value when  
the external event occurs. The capture register eliminates  
the latency time, thereby allowing the applications program  
to retrieve the timer value stored in the capture register.  
Figure 17 shows a block diagram of the timer in Input Cap-  
ture mode.  
In this mode, the timer T1 is constantly running at the fixed tC  
rate. The two registers, R1A and R1B, act as capture regis-  
ters. Each register acts in conjunction with a pin. The register  
R1A acts in conjunction with the T1A pin and the register  
R1B acts in conjunction with the T1B pin.  
The timer value gets copied over into the register when a  
trigger event occurs on its corresponding pin. Control bits,  
T1C3, T1C2 and T1C1, allow the trigger events to be speci-  
fied either as a positive or a negative edge. The trigger  
condition for each input pin can be specified independently.  
The trigger conditions can also be programmed to generate  
interrupts. The occurrence of the specified trigger condition  
on the T1A and T1B pins will be respectively latched into the  
pending flags, T1PNDA and T1PNDB. The control flag  
T1ENA allows the interrupt on T1A to be either enabled or  
disabled. Setting the T1ENA flag enables interrupts to be  
generated when the selected trigger condition occurs on the  
T1A pin. Similarly, the flag T1ENB controls the interrupts  
from the T1B pin.  
20091733  
FIGURE 17. Timer in Input Capture Mode  
21  
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T1PNDA Timer Interrupt Pending Flag  
T1ENA Timer Interrupt Enable Flag  
1 = Timer Interrupt Enabled  
11.0 Timers (Continued)  
11.6 TIMER CONTROL FLAGS  
The control bits and their functions are summarized below.  
0 = Timer Interrupt Disabled  
T1C3  
T1C2  
T1C1  
T1C0  
Timer mode control  
Timer mode control  
Timer mode control  
T1PNDB Timer Interrupt Pending Flag  
T1ENB Timer Interrupt Enable Flag  
1 = Timer Interrupt Enabled  
Timer Start/Stop control in Modes 1 and 2 (Pro-  
cessor Independent PWM and External Event  
Counter), where 1 = Start, 0 = Stop  
0 = Timer Interrupt Disabled  
The timer mode control bits (T1C3, T1C2 and T1C1) are  
detailed below:  
Timer Underflow Interrupt Pending Flag in Mode  
3 (Input Capture)  
Interrupt A  
Source  
Interrupt B  
Source  
Timer  
Counts On  
Mode  
T1C3  
T1C2  
T1C1  
Description  
1
1
0
0
1
0
PWM: T1A Toggle  
PWM: No T1A  
Toggle  
Autoreload RA  
Autoreload RA  
Autoreload RB  
Autoreload RB  
tC  
1
tC  
0
0
0
0
0
1
0
1
0
External Event  
Counter  
Timer Underflow Pos. T1B Edge  
Timer Underflow Pos. T1B Edge  
Pos. T1A  
Edge  
2
External Event  
Counter  
Pos. T1A  
Edge  
Captures:  
Pos. T1A Edge  
or Timer  
Pos. T1B Edge  
tC  
T1A Pos. Edge  
T1B Pos. Edge  
Captures:  
Underflow  
1
0
1
1
1
1
0
1
1
Pos. T1A  
Neg. T1B  
Edge  
tC  
tC  
tC  
T1A Pos. Edge  
T1B Neg. Edge  
Captures:  
Edge or Timer  
Underflow  
3
Neg. T1A  
Neg. T1B  
Edge  
T1A Neg. Edge  
T1B Neg. Edge  
Captures:  
Edge or Timer  
Underflow  
Neg. T1A  
Neg. T1B  
Edge  
T1A Neg. Edge  
T1B Neg. Edge  
Edge or Timer  
Underflow  
activities are stopped. In the IDLE mode, the on-board os-  
cillator circuitry and timer T0 are active but all other micro-  
controller activities are stopped. In either mode, all on-board  
RAM, registers, I/O states, and timers (with the exception of  
T0) are unaltered.  
12.0 Power Save Modes  
Today, the proliferation of battery-operated based applica-  
tions has placed new demands on designers to drive power  
consumption down. Battery-operated systems are not the  
only type of applications demanding low power. The power  
budget constraints are also imposed on those consumer/  
industrial applications where well regulated and expensive  
power supply costs cannot be tolerated. Such applications  
rely on low cost and low power supply voltage derived di-  
rectly from the “mains” by using voltage rectifier and passive  
components. Low power is demanded even in automotive  
applications, due to increased vehicle electronics content.  
This is required to ease the burden from the car battery. Low  
power 8-bit microcontrollers supply the smarts to control  
battery-operated, consumer/industrial, and automotive appli-  
cations.  
Clock Monitor if enabled can be active in both modes.  
12.1 HALT MODE  
The device can be placed in the HALT mode by writing a “1”  
to the HALT flag (G7 data bit). All microcontroller activities,  
including the clock and timers, are stopped. The WATCH-  
DOG logic on the device is disabled during the HALT mode.  
However, the clock monitor circuitry, if enabled, remains  
active and will cause the WATCHDOG output pin (WDOUT)  
to go low. If the HALT mode is used and the user does not  
want to activate the WDOUT pin, the Clock Monitor should  
be disabled after the device comes out of reset (resetting the  
Clock Monitor control bit with the first write to the WDSVR  
register). In the HALT mode, the power requirements of the  
device are minimal and the applied voltage (VCC) may be  
decreased to Vr (Vr = 2.0V) without altering the state of the  
machine.  
The COP8TAx devices offer system designers a variety of  
low-power consumption features that enable them to meet  
the demanding requirements of today’s increasing range of  
low-power applications. These features include low voltage  
operation, low current drain, and power saving features such  
as HALT, IDLE, and Multi-Input Wake-Up (MIWU).  
The device supports three different ways of exiting the HALT  
mode. The first method of exiting the HALT mode is with the  
Multi-Input Wake-Up feature on Port L and Port C. The  
The devices offer the user two power save modes of opera-  
tion: HALT and IDLE. In the HALT mode, all microcontroller  
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22  
If an R/C clock option is being used, the fixed delay is  
introduced optionally. A control bit, CLKDLY, mapped as  
configuration bit G7, controls whether the delay is to be  
introduced or not. The delay is included if CLKDLY is set,  
and excluded if CLKDLY is reset. The CLKDLY bit is cleared  
on reset.  
12.0 Power Save Modes (Continued)  
second method is with a low to high transition on the CKO  
(G7) pin. This method precludes the use of the crystal clock  
configuration (since CKO becomes a dedicated output), and  
so may only be used with an R/C clock configuration. The  
third method of exiting the HALT mode is by pulling the  
RESET pin low.  
The device has two options associated with the HALT mode.  
The first option enables the HALT mode feature, while the  
second option disables the HALT mode selected through bit  
0 of the Option Byte. With the HALT mode enable option, the  
device will enter and exit the HALT mode as described  
above. With the HALT disable option, the device cannot be  
placed in the HALT mode (writing a “1” to the HALT flag will  
have no effect, the HALT flag will remain “0”).  
Since a crystal or ceramic resonator may be selected as the  
oscillator, the Multi-Input Wake-Up signal is not allowed to  
start the chip running immediately since crystal oscillators  
and ceramic resonators have a delayed start up time to  
reach full amplitude and frequency stability. The IDLE timer  
is used to generate a fixed delay to ensure that the oscillator  
has indeed stabilized before allowing instruction execution.  
In this case, upon detecting a valid Multi-Input Wake-Up  
signal, only the oscillator circuitry is enabled. The IDLE timer  
is loaded with a value of 256 and is clocked with the tC  
instruction cycle clock. The tC clock is derived by dividing the  
oscillator clock down by a factor of 10. The Schmitt trigger  
following the CKI inverter on the chip ensures that the IDLE  
timer is clocked only when the oscillator has a sufficiently  
large amplitude to meet the Schmitt trigger specifications.  
This Schmitt trigger is not part of the oscillator closed loop.  
The start-up time-out from the IDLE timer enables the clock  
signals to be routed to the rest of the chip.  
The WATCHDOG detector circuit is inhibited during the  
HALT mode. However, the clock monitor circuit if enabled  
remains active during HALT mode in order to ensure a clock  
monitor error if the device inadvertently enters the HALT  
mode as a result of a runaway program or power glitch.  
If the device is placed in the HALT mode, with the R/C  
oscillator selected, the clock input pin (CKI) is forced to a  
logic high internally. With the crystal or external oscillator the  
CKI pin is TRI-STATE.  
20091734  
FIGURE 18. Multi-Input Wake-Up from HALT  
12.2 IDLE MODE  
The user can enter the IDLE mode with the Timer T0 inter-  
rupt enabled. In this case, when the T0PND bit gets set, the  
device will first execute the Timer T0 interrupt service routine  
and then return to the instruction following the “Enter Idle  
Mode” instruction.  
The device is placed in the IDLE mode by writing a “1” to the  
IDLE flag (G6 data bit). In this mode, all activities, except the  
associated on-board oscillator circuitry and the IDLE Timer  
T0, are stopped.  
Alternatively, the user can enter the IDLE mode with the  
IDLE Timer T0 interrupt disabled. In this case, the device will  
resume normal operation with the instruction immediately  
following the “Enter IDLE Mode” instruction.  
Note: It is necessary to program two NOP instructions following both the set  
HALT mode and set IDLE mode instructions. These NOP instructions  
are necessary to allow clock resynchronization following the HALT or  
IDLE modes.  
As with the HALT mode, the device can be returned to  
normal operation with a reset, or with a Multi-Input Wake-Up  
from the L Port. Alternately, the microcontroller resumes  
normal operation from the IDLE mode when the twelfth bit  
(representing 4.096 ms at internal clock frequency of  
10 MHz, tC = 1 µs) of the IDLE Timer toggles.  
This toggle condition of the twelfth bit of the IDLE Timer T0 is  
latched into the T0PND pending flag.  
The user has the option of being interrupted with a transition  
on the twelfth bit of the IDLE Timer T0. The interrupt can be  
enabled or disabled via the T0EN control bit. Setting the  
T0EN flag enables the interrupt and vice versa.  
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12.0 Power Save Modes (Continued)  
20091735  
FIGURE 19. Wake-Up from IDLE  
12.3 MULTI-INPUT WAKE-UP  
ing bit in CWKPND or LWKPND remains set until cleared by  
software. The device will not enter HALT or IDLE mode if any  
Wake-Up input is both enabled and pending.  
The Multi-Input Wake-Up feature is used to exit from the  
HALT and IDLE modes. In addition, the Multi-Input Wake-  
Up/Interrupt feature may be used to generate up to 16  
edge-selectable external interrupts on the 44-pin devices or  
8 interrupts on the 20- and 28-pin devices. Figure 20 shows  
the Multi-Input Wake-Up logic.  
Changing a trigger condition control bit requires several  
steps to avoid generating a spurious Wake-Up event or  
interrupt as a side effect  
First, the corresponding CWKEN or LWKEN bit should be  
cleared to disable any Wake-Up event or interrupt for that  
port pin.  
The Multi-Input Wake-Up feature uses the C and L ports.  
(The 20- and 28-pin devices only have the L port.) Software  
selects which port bit (or set of port bits) may cause the  
device to exit the HALT or IDLE modes. The selection is  
controlled by the CWKEN and LWKEN registers. These  
registers are 8-bit read/write registers, which contain control  
bits that correspond to the C and L port bits. Setting a  
CWKEN or LWKEN bit enables a Wake-Up event or interrupt  
from the associated C or L port pin.  
Second, the trigger condition is selected in CWKEDG or  
LWKEDG.  
Third, any spurious pending event is removed by clearing  
the associated bit in CWKPND or LWKPND.  
Finally, the trigger is re-enabled by setting the associated  
bit in CWKEN or LWKEN.  
An example shows how software performs this procedure.  
Assume the trigger condition for L port bit 5 is to be changed  
from positive (low-to-high transition) to negative (high-to-low  
transition), and bit 5 has previously been enabled for an  
input interrupt. Software would execute the following instruc-  
tions:  
If the ACCESS.Bus module is enabled, port pin L0 may also  
be used to generate a Wake-Up event on ACCESS.Bus  
activity. Please see the section on Section 16.0 ACCESS-  
.Bus Interface for more information.  
Software selects whether the trigger condition on the se-  
lected port pin is a positive edge (low-to-high transition) or a  
negative edge (high-to-low transition). The trigger conditions  
are selected in the CWKEDG and LWKEDG registers, which  
are 8-bit control registers with bits corresponding to the C  
and L port pins. Setting a trigger condition control bit selects  
the negative edge, while clearing the bit selects the positive  
edge.  
RBIT 5, LWKEN  
; Disable MIWU Port L.5  
SBIT 5, LWKEDG ; Change edge polarity  
RBIT 5, LWKPND ; Reset pending flag  
SBIT 5, LWKEN  
; Enable MIWU Port L.5  
If the C or L port pins have been used as outputs and then  
changed to inputs using the Multi-Input Wake-Up feature, a  
safe procedure should be used to avoid generating a spuri-  
ous Wake-Up event or interrupt. After the selected C or L  
port pins have been changed from output to input, the trigger  
conditions are selected in CWKEDG or LWKEDG and the  
pending bits in CWKPND or LWKPND are cleared. Finally,  
the CWKEN or LWKEN bits are set to enable the desired  
Wake-Up events or interrupts.  
The occurrence of a selected trigger condition is latched in  
the pending registers called CWKPND and LWKPND. The  
bits of these registers correspond to the C and L port pins.  
These bits are set on the occurrence of the selected trigger  
condition on the corresponding port pin, whether or not the  
trigger condition is enabled in CWKEN or LWKEN. Software  
has responsibility for clearing the pending bits before en-  
abling them for Wake-Up events or interrupts. Any set pend-  
The same procedure should be used following reset, be-  
cause the C and L port pins are left floating. The CWKPND  
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24  
CWKEN and LWKEN are read/write registers that are  
cleared at reset, so no Wake-Up events or interrupts are  
enabled following reset. CWKEDG and LWKEDG are also  
cleared at reset.  
12.0 Power Save Modes (Continued)  
and LWKPND registers contain undefined values after reset,  
so software should clear these bits after reset to ensure that  
no spurious Wake-Up events or interrupts are left pending.  
20091781  
FIGURE 20. Multi-Input Wake-Up Logic  
The Software trap has the highest priority while the default  
VIS has the lowest priority.  
13.0 Interrupts  
Each of the 13 maskable inputs has a fixed arbitration rank-  
ing and vector.  
13.1 INTRODUCTION  
The device supports eleven vectored interrupts. Interrupt  
sources include Timer 1, Timer 2, Timer T0, Multi-Input  
Wake-Up, Software Trap, MICROWIRE/PLUS and External  
Input.  
Figure 21 shows the Interrupt block diagram.  
All interrupts force a branch to location 00FF Hex in program  
memory. The VIS instruction may be used to vector to the  
appropriate service routine from location 00FF Hex.  
25  
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13.0 Interrupts (Continued)  
20091776  
FIGURE 21. Interrupt Block Diagram  
13.2 MASKABLE INTERRUPTS  
enabled; if the pending bit is already set, it will immediately  
trigger an interrupt. A maskable interrupt is active if its asso-  
ciated enable and pending bits are set.  
All interrupts other than the Software Trap are maskable.  
Each maskable interrupt has an associated enable bit and  
pending flag bit. The pending bit is set to 1 when the interrupt  
condition occurs. The state of the interrupt enable bit, com-  
bined with the GIE bit determines whether an active pending  
flag actually triggers an interrupt. All of the maskable inter-  
rupt pending and enable bits are contained in mapped con-  
trol registers, and thus can be controlled by the software.  
An interrupt is an asychronous event which may occur be-  
fore, during, or after an instruction cycle. Any interrupt which  
occurs during the execution of an instruction is not acknowl-  
edged until the start of the next normally executed instruc-  
tion. If the next normally executed instruction is to be  
skipped, the skip is performed before the pending interrupt is  
acknowledged.  
A maskable interrupt condition triggers an interrupt under the  
following conditions:  
At the start of interrupt acknowledgment, the following ac-  
tions occur:  
1. The enable bit associated with that interrupt is set.  
2. The GIE bit is set.  
1. The GIE bit is automatically reset to zero, preventing any  
subsequent maskable interrupt from interrupting the cur-  
rent service routine. This feature prevents one maskable  
interrupt from interrupting another one being serviced.  
3. The device is not processing a non-maskable interrupt.  
(If  
a non-maskable interrupt is being serviced, a  
maskable interrupt must wait until that service routine is  
completed.)  
2. The address of the instruction about to be executed is  
pushed onto the stack.  
An interrupt is triggered only when all of these conditions are  
met at the beginning of an instruction. If different maskable  
interrupts meet these conditions simultaneously, the highest-  
priority interrupt will be serviced first, and the other pending  
interrupts must wait.  
3. The program counter (PC) is loaded with 00FF Hex,  
causing a jump to that program memory location.  
The device requires seven instruction cycles to perform the  
actions listed above.  
Upon Reset, all pending bits, individual enable bits, and the  
GIE bit are reset to zero. Thus, a maskable interrupt condi-  
tion cannot trigger an interrupt until the program enables it by  
setting both the GIE bit and the individual enable bit. When  
enabling an interrupt, the user should consider whether or  
not a previously activated (set) pending bit should be ac-  
knowledged. If, at the time an interrupt is enabled, any  
previous occurrences of the interrupt should be ignored, the  
associated pending bit must be reset to zero prior to en-  
abling the interrupt. Otherwise, the interrupt may be simply  
If the user wishes to allow nested interrupts, the interrupts  
service routine may set the GIE bit to 1 by writing to the PSW  
register, and thus allow other maskable interrupts to interrupt  
the current service routine. If nested interrupts are allowed,  
caution must be exercised. The user must write the program  
in such a way as to prevent stack overflow, loss of saved  
context information, and other unwanted conditions.  
The interrupt service routine stored at location 00FF Hex  
should use the VIS instruction to determine the cause of the  
interrupt, and jump to the interrupt handling routine corre-  
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26  
next priority interrupt is located at 0yE2 and 0yE3, and so  
forth in increasing rank. The Software Trap has the highest  
rand and its vector is always located at 0yFE and 0yFF. The  
number of interrupts which can become active defines the  
size of the table.  
13.0 Interrupts (Continued)  
sponding to the highest priority enabled and active interrupt.  
Alternately, the user may choose to poll all interrupt pending  
and enable bits to determine the source(s) of the interrupt. If  
more than one interrupt is active, the user’s program must  
decide which interrupt to service.  
Table 7 shows the types of interrupts, the interrupt arbitration  
ranking, and the locations of the corresponding vectors in  
the vector table.  
Within a specific interrupt service routine, the associated  
pending bit should be cleared. This is typically done as early  
as possible in the service routine in order to avoid missing  
the next occurrence of the same type of interrupt event.  
Thus, if the same event occurs a second time, even while the  
first occurrence is still being serviced, the second occur-  
rence will be serviced immediately upon return from the  
current interrupt routine.  
The vector table should be filled by the user with the memory  
locations of the specific interrupt service routines. For ex-  
ample, if the Software Trap routine is located at 0310 Hex,  
then the vector location 0yFE and -0yFF should contain the  
data 03 and 10 Hex, respectively. When a Software Trap  
interrupt occurs and the VIS instruction is executed, the  
program jumps to the address specified in the vector table.  
An interrupt service routine typically ends with an RETI  
instruction. This instruction set the GIE bit back to 1, pops  
the address stored on the stack, and restores that address to  
the program counter. Program execution then proceeds with  
the next instruction that would have been executed had  
there been no interrupt. If there are any valid interrupts  
pending, the highest-priority interrupt is serviced immedi-  
ately upon return from the previous interrupt.  
The interrupt sources in the vector table are listed in order of  
rank, from highest to lowest priority. If two or more enabled  
and pending interrupts are detected at the same time, the  
one with the highest priority is serviced first. Upon return  
from the interrupt service routine, the next highest-level  
pending interrupt is serviced.  
If the VIS instruction is executed, but no interrupts are en-  
abled and pending, the lowest-priority interrupt vector is  
used, and a jump is made to the corresponding address in  
the vector table. This is an unusual occurrence and may be  
the result of an error. It can legitimately result from a change  
in the enable bits or pending flags prior to the execution of  
the VIS instruction, such as executing a single cycle instruc-  
tion which clears an enable flag at the same time that the  
pending flag is set. It can also result, however, from inad-  
vertent execution of the VIS command outside of the context  
of an interrupt.  
Note: While executing from the Boot ROM for ISP or virtual  
E2 operations, the hardware will disable interrupts from oc-  
curring. The hardware will leave the GIE bit in its current  
state, and if set, the hardware interrupts will occur when  
execution is returned to ROM Memory. Subsequent inter-  
rupts, during ISP operation, from the same interrupt source  
will be lost.  
13.3 VIS INSTRUCTION  
The general interrupt service routine, which starts at address  
00FF Hex, must be capable of handling all types of inter-  
rupts. The VIS instruction, together with an interrupt vector  
table, directs the device to the specific interrupt handling  
routine based on the cause of the interrupt.  
The default VIS interrupt vector can be useful for applica-  
tions in which time critical interrupts can occur during the  
servicing of another interrupt. Rather than restoring the pro-  
gram context (A, B, X, etc.) and executing the RETI instruc-  
tion, an interrupt service routine can be terminated by return-  
ing to the VIS instruction. In this case, interrupts will be  
serviced in turn until no further interrupts are pending and  
the default VIS routine is started. After testing the GIE bit to  
ensure that execution is not erroneous, the routine should  
restore the program context and execute the RETI to return  
to the interrupted program.  
VIS is a single-byte instruction, typically used at the very  
beginning of the general interrupt service routine at address  
00FF Hex, or shortly after that point, just after the code used  
for context switching. The VIS instruction determines which  
enabled and pending interrupt has the highest priority, and  
causes an indirect jump to the address corresponding to that  
interrupt source. The jump addresses (vectors) for all pos-  
sible interrupts sources are stored in a vector table.  
This technique can save up to fifty instruction cycles (tC), or  
more, (100 µs at 10 MHz oscillator) of latency for pending  
interrupts with a penalty of fewer than ten instruction cycles  
if no further interrupts are pending.  
The vector table may be as long as 32 bytes (maximum of 16  
vectors) and resides at the top of the 256-byte block con-  
taining the VIS instruction. However, if the VIS instruction is  
at the very top of a 256-byte block (such as at 00FF Hex),  
the vector table resides at the top of the next 256-byte block.  
Thus, if the VIS instruction is located somewhere between  
00FF and 01DF Hex (the usual case), the vector table is  
located between addresses 01E0 and 01FF Hex. If the VIS  
instruction is located between 01FF and 02DF Hex, then the  
vector table is located between addresses 02E0 and 02FF  
Hex, and so on.  
To ensure reliable operation, the user should always use the  
VIS instruction to determine the source of an interrupt. Al-  
though it is possible to poll the pending bits to detect the  
source of an interrupt, this practice is not recommended. The  
use of polling allows the standard arbitration ranking to be  
altered, but the reliability of the interrupt system is compro-  
mised. The polling routine must individually test the enable  
and pending bits of each maskable interrupt. If a Software  
Trap interrupt should occur, it will be serviced last, even  
though it should have the highest priority. Under certain  
conditions, a Software Trap could be triggered but not ser-  
viced, resulting in an inadvertent “locking out” of all  
maskable interrupts by the Software Trap pending flag.  
Problems such as this can be avoided by using VIS  
instruction.  
Each vector is 15 bits long and points to the beginning of a  
specific interrupt service routine somewhere in the 32-kbyte  
memory space. Each vector occupies two bytes of the vector  
table, with the higher-order byte at the lower address. The  
vectors are arranged in order of interrupt priority. The vector  
of the maskable interrupt with the lowest rank is located to  
0yE0 (higher-order byte) and 0yE1 (lower-order byte). The  
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13.0 Interrupts (Continued)  
TABLE 7. Interrupt Vector Table  
Vector Address (Note 7)  
Arbitration Ranking  
Source Description  
(Hi-Low Byte)  
(1) Highest  
Software  
INTR Instruction  
0yFE–0yFF  
(2)  
(3)  
(4)  
(5)  
(6)  
(7)  
(8)  
Reserved for NMI  
External  
0yFC–0yFD  
0yFA–0yFB  
0yF8–0yF9  
0yF6–0yF7  
0yF4–0yF5  
0yF2–0yF3  
G0  
Timer T0  
Underflow  
T1A/Underflow  
T1B  
Timer T1  
Timer T1  
MICROWIRE/PLUS  
ACCESS.Bus  
BUSY Low  
Address Match, Bus Error, 0yF0–0yF1  
Negative Acknowledge,  
Valid Sto or SDAST is set  
0yEE–0yEF  
(9)  
Reserved  
(10)  
(11)  
(12)  
(13)  
(14)  
(15)  
Reserved  
0yEC–0yED  
Reserved  
0yEA–0yEB  
Reserved  
0yE8–0yE9  
Reserved  
0yE6–0yE7  
Reserved  
0yE4–0yE5  
Port L/Wake-up  
Port C/Wake-up  
Default VIS  
Port L Edge  
Port C Edge  
Reserved  
0yE2–0yE3  
(16) Lowest  
0yE0–0yE1  
Note 7: y is a variable which represents the VIS block. VIS and the vector table must be located in the same 256-byte block except if VIS is located at the last  
address of a block. In this case, the table must be in the next block.  
13.3.1 VIS Execution  
the active interrupt with the highest arbitration ranking. This  
vector is read from program memory and placed into the PC  
which is now pointed to the 1st instruction of the service  
routine of the active interrupt with the highest arbitration  
ranking.  
When the VIS instruction is executed it activates the arbitra-  
tion logic. The arbitration logic generates an even number  
between E0 and FE (E0, E2, E4, E6 etc....) depending on  
which active interrupt has the highest arbitration ranking at  
the time of the 1st cycle of VIS is executed. For example, if  
the software trap interrupt is active, FE is generated. If the  
external interrupt is active and the software trap interrupt is  
not, then FA is generated and so forth. If no active interrupt  
is pending, than E0 is generated. This number replaces the  
lower byte of the PC. The upper byte of the PC remains  
unchanged. The new PC is therefore pointing to the vector of  
Figure 22 illustrates the different steps performed by the VIS  
instruction. Figure 23 shows a flowchart for the VIS instruc-  
tion.  
The non-maskable interrupt pending flag is cleared by the  
RPND (Reset Non-Maskable Pending Bit) instruction (under  
certain conditions) and upon RESET.  
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13.0 Interrupts (Continued)  
20091777  
FIGURE 22. VIS Operation  
13.4 NON-MASKABLE INTERRUPT  
13.4.1 Pending Flag  
Nothing can interrupt a Software Trap service routine except  
for another Software Trap. The STPND can be reset only by  
the RPND instruction or a chip Reset.  
There is a pending flag bit associated with the non-maskable  
Software Trap interrupt, called STPND. This pending flag is  
not memory-mapped and cannot be accessed directly by the  
software.  
The Software Trap indicates an unusual or unknown error  
condition. Generally, returning to normal execution at the  
point where the Software Trap occurred cannot be done  
reliably. Therefore, the Software Trap service routine should  
re-initialize the stack pointer and perform a recovery proce-  
dure that re-starts the software at some known point, similar  
to a device Reset, but not necessarily performing all the  
same functions as a device Reset. The routine must also  
execute the RPND instruction to reset the STPND flag.  
Otherwise, all other interrupts will be locked out. To the  
extent possible, the interrupt routine should record or indi-  
cate the context of the device so that the cause of the  
Software Trap can be determined.  
The pending flag is reset to zero when a device Reset  
occurs. When the non-maskable interrupt occurs, the asso-  
ciated pending bit is set to 1. The interrupt service routine  
should contain an RPND instruction to reset the pending flag  
to zero. The RPND instruction always resets the STPND  
flag.  
13.4.2 Software Trap  
The Software Trap is a special kind of non-maskable inter-  
rupt which occurs when the INTR instruction (used to ac-  
knowledge interrupts) is fetched from program memory and  
placed in the instruction register. This can happen in a  
variety of ways, usually because of an error condition. Some  
examples of causes are listed below.  
If the user wishes to return to normal execution from the  
point at which the Software Trap was triggered, the user  
must first execute RPND, followed by RETSK rather than  
RETI or RET. This is because the return address stored on  
the stack is the address of the INTR instruction that triggered  
the interrupt. The program must skip that instruction in order  
to proceed with the next one. Otherwise, an infinite loop of  
Software Traps and returns will occur.  
If the program counter incorrectly points to a memory loca-  
tion beyond the programmed ROM memory space, the un-  
used memory location returns zeros which is interpreted as  
the INTR instruction.  
Programming a return to normal execution requires careful  
consideration. If the Software Trap routine is interrupted by  
another Software Trap, the RPND instruction in the service  
routine for the second Software Trap will reset the STPND  
flag; upon return to the first Software Trap routine, the  
STPND flag will have the wrong state. This will allow  
maskable interrupts to be acknowledged during the servicing  
of the first Software Trap. To avoid problems such as this, the  
A Software Trap can be triggered by a temporary hardware  
condition such as a brownout or power supply glitch.  
The Software Trap has the highest priority of all interrupts.  
When a Software Trap occurs, the STPND bit is set. The GIE  
bit is not affected and the pending bit (not accessible by the  
user) is used to inhibit other interrupts and to direct the  
program to the ST service routine with the VIS instruction.  
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programming error or hardware condition (brownout, power  
supply glitch, etc.) sets the STPND flag without providing a  
way for it to be cleared, all other interrupts will be locked out.  
To alleviate this condition, the user can use extra RPND  
instructions in the main program and in the Watchdog ser-  
vice routine (if present). There is no harm in executing extra  
RPND instructions in these parts of the program.  
13.0 Interrupts (Continued)  
user program should contain the Software Trap routine to  
perform a recovery procedure rather than a return to normal  
execution.  
Under normal conditions, the STPND flag is reset by a  
RPND instruction in the Software Trap service routine. If a  
20091778  
FIGURE 23. VIS Flow Chart  
13.4.2.1 Programming Example: External Interrupt  
PSW  
CNTRL  
RBIT  
RBIT  
SBIT  
SBIT  
SBIT  
JP  
=00EF  
=00EE  
0,PORTGC  
0,PORTGD  
IEDG, CNTRL  
GIE, PSW  
EXEN, PSW  
WAIT  
; G0 pin configured Hi-Z  
; Ext interrupt polarity; falling edge  
; Set the GIE bit  
; Enable the external interrupt  
; Wait for external interrupt  
WAIT:  
.
.
.
.=0FF  
VIS  
; The interrupt causes a  
; branch to address 0FF  
; The VIS causes a branch to  
; interrupt vector table  
.
.
.
.=01FA  
.ADDRW SERVICE  
; Vector table (within 256 byte  
; of VIS inst.) containing the ext  
; interrupt service routine  
.
.
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30  
13.0 Interrupts (Continued)  
.
SERVICE:  
; Interrupt Service Routine  
RBIT,EXPND,PSW  
; Reset ext interrupt pend. bit  
.
.
.
RET I  
; Return, set the GIE bit  
13.5 PORT C AND PORT L INTERRUPTS  
terrupts, during ISP operation, from the same interrupt  
source will be lost.  
Ports C and L provides the user with an additional sixteen  
fully selectable, edge sensitive interrupts which are all vec-  
tored into the same service subroutine.  
14.0 WATCHDOG/Clock Monitor  
The interrupt from Ports C and L share logic with the  
wake-up circuitry. The registers CWKEN and LWKEN allow  
interrupts from Ports C and L to be individually enabled or  
disabled. The register CWKEDG and LWKEDG specify the  
trigger condition to be either a positive or a negative edge.  
Finally, the registers CWKPND and LWKPND latch in the  
pending trigger conditions.  
The devices contain a user selectable WATCHDOG and  
clock monitor. The following section is applicable only if  
WATCHDOG feature has been selected in the Option Byte.  
The WATCHDOG is designed to detect the user program  
getting stuck in infinite loops resulting in loss of program  
control or “runaway” programs.  
The WATCHDOG logic contains two separate service win-  
dows. While the user programmable upper window selects  
the WATCHDOG service time, the lower window provides  
protection against an infinite program loop that contains the  
WATCHDOG service instruction.  
The GIE (Global Interrupt Enable) bit enables the interrupt  
function.  
A control flag, LPEN, functions as a global interrupt enable  
for Port C and Port L interrupts. Setting the LPEN flag will  
enable interrupts and vice versa. A separate global pending  
flag is not needed since the registers CWKPND and LWK-  
PND are adequate.  
The COP8TAx devices provide the added feature of a soft-  
ware trap that provides protection against stack overpops  
and addressing locations outside valid user program space.  
Since Ports C and L are also used for waking the device out  
of the HALT or IDLE modes, the user can elect to exit the  
HALT or IDLE modes either with or without the interrupt  
enabled. If he elects to disable the interrupt, then the device  
will restart execution from the instruction immediately follow-  
ing the instruction that placed the microcontroller in the  
HALT or IDLE modes. In the other case, the device will first  
execute the interrupt service routine and then revert to nor-  
mal operation.  
The Clock Monitor is used to detect the absence of a clock or  
a very slow clock below a specified rate on the CKI pin.  
The WATCHDOG consists of two independent logic blocks:  
WD UPPER and WD LOWER. WD UPPER establishes the  
upper limit on the service window and WD LOWER defines  
the lower limit of the service window.  
Servicing the WATCHDOG consists of writing a specific  
value to a WATCHDOG Service Register named WDSVR  
which is memory mapped in the RAM. This value is com-  
posed of three fields, consisting of a 2-bit Window Select, a  
5-bit Key Data field, and the 1-bit Clock Monitor Select field.  
Table 8 shows the WDSVR register.  
13.6 INTERRUPT SUMMARY  
The device uses the following types of interrupts, listed  
below in order of priority:  
1. The Software Trap non-maskable interrupt, triggered by  
the INTR (00 opcode) instruction. The Software Trap is  
acknowledged immediately. This interrupt service rou-  
tine can be interrupted only by another Software Trap.  
The Software Trap should end with two RPND instruc-  
tions followed by a re-start procedure.  
TABLE 8. WATCHDOG Service Register (WDSVR)  
Window  
Select  
Key Data  
Clock  
Monitor  
Y
X
X
0
1
1
0
0
2. Maskable interrupts, triggered by an on-chip peripheral  
block or an external device connected to the device.  
Under ordinary conditions, a maskable interrupt will not  
interrupt any other interrupt routine in progress. A  
maskable interrupt routine in progress can be inter-  
The lower limit of the service window is fixed at 256 instruc-  
tion cycles. Bits 7 and 6 of the WDSVR register allow the  
user to pick an upper limit of the service window.  
Table 9 shows the four possible combinations of lower and  
upper limits for the WATCHDOG service window. This flex-  
ibility in choosing the WATCHDOG service window prevents  
any undue burden on the user software.  
rupted by the non-maskable interrupt request.  
A
maskable interrupt routine should end with an RETI  
instruction or, prior to restoring context, should return to  
execute the VIS instruction. This is particularly useful  
when exiting long interrupt service routines if the time  
between interrupts is short. In this case the RETI instruc-  
tion would only be executed when the default VIS rou-  
tine is reached.  
Bits 5, 4, 3, 2 and 1 of the WDSVR register represent the  
5-bit Key Data field. The key data is fixed at 01100. Bit 0 of  
the WDSVR Register is the Clock Monitor Select bit.  
TABLE 9. WATCHDOG Service Window Select  
3. While executing from the Boot ROM for ISP or virtual E2  
operations, the hardware will disable interrupts from oc-  
curring. The hardware will leave the GIE bit in its current  
state, and if set, the hardware interrupts will occur when  
execution is returned to ROM Memory. Subsequent in-  
WDSVR WDSVR Clock  
Service Window  
(Lower-Upper Limits)  
256–8k tC Cycles  
Bit 7  
Bit 6  
Monitor  
0
0
0
1
x
x
256–16k tC Cycles  
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DOG key data. Subsequent writes to the WDSVR register  
will compare the value being written by the user to the  
WATCHDOG service window value and the key data (bits 7  
through 1) in the WDSVR Register. Table 10 shows the  
sequence of events that can occur.  
14.0 WATCHDOG/Clock Monitor  
(Continued)  
TABLE 9. WATCHDOG Service Window  
Select (Continued)  
The user must service the WATCHDOG at least once before  
the upper limit of the service window expires. The WATCH-  
DOG may not be serviced more than once in every lower  
limit of the service window. The user may service the  
WATCHDOG as many times as wished in the time period  
between the lower and upper limits of the service window.  
The first write to the WDSVR Register is also counted as a  
WATCHDOG service.  
WDSVR WDSVR Clock  
Service Window  
(Lower-Upper Limits)  
256–32k tC Cycles  
Bit 7  
Bit 6  
Monitor  
1
1
x
x
0
1
x
x
x
x
0
1
256–64k tC Cycles  
Clock Monitor Disabled  
Clock Monitor Enabled  
The WATCHDOG has an output pin associated with it. This  
is the WDOUT pin, on pin 1 of the port G. WDOUT is active  
low and must be externally connected to the RESET pin or to  
some other external logic which handles WATCHDOG event.  
The WDOUT pin has a weak pullup in the inactive state. This  
pull-up is sufficient to serve as the connection to VCC for  
systems which use the internal Power On Reset. Upon  
triggering the WATCHDOG, the logic will pull the WDOUT  
(G1) pin low for an additional 16 tC–32 tC cycles after the  
signal level on WDOUT pin goes below the lower Schmitt  
trigger threshold. After this delay, the device will stop forcing  
the WDOUT output low. The WATCHDOG service window  
will restart when the WDOUT pin goes high.  
14.1 CLOCK MONITOR  
The Clock Monitor aboard the device can be selected or  
deselected under program control. The Clock Monitor is  
guaranteed not to reject the clock if the instruction cycle  
clock (1/tC) is greater or equal to 10 kHz. This equates to a  
clock input rate on CKI of greater or equal to 100 kHz.  
14.2 WATCHDOG/CLOCK MONITOR OPERATION  
The WATCHDOG is enabled by bit 2 of the Option Byte.  
When this Option bit is 0, the WATCHDOG is enabled and  
pin G1 becomes the WATCHDOG output with a weak pullup.  
The WATCHDOG and Clock Monitor are disabled during  
reset. The device comes out of reset with the WATCHDOG  
armed, the WATCHDOG Window Select bits (bits 6, 7 of the  
WDSVR Register) set, and the Clock Monitor bit (bit 0 of the  
WDSVR Register) enabled. Thus, a Clock Monitor error will  
occur after coming out of reset, if the instruction cycle clock  
frequency has not reached a minimum specified value, in-  
cluding the case where the oscillator fails to start.  
A WATCHDOG service while the WDOUT signal is active will  
be ignored. The state of the WDOUT pin is not guaranteed  
on reset, but if it powers up low then the WATCHDOG will  
time out and WDOUT will go high.  
The Clock Monitor forces the G1 pin low upon detecting a  
clock frequency error. The Clock Monitor error will continue  
until the clock frequency has reached the minimum specified  
value, after which the G1 output will go high following 16  
tC–32 tC clock cycles. The Clock Monitor generates a con-  
tinual Clock Monitor error if the oscillator fails to start, or fails  
to reach the minimum specified frequency. The specification  
for the Clock Monitor is as follows:  
The WDSVR register can be written to only once after reset  
and the key data (bits 5 through 1 of the WDSVR Register)  
must match to be a valid write. This write to the WDSVR  
register involves two irrevocable choices: (i) the selection of  
the WATCHDOG service window (ii) enabling or disabling of  
the Clock Monitor. Hence, the first write to WDSVR Register  
involves selecting or deselecting the Clock Monitor, select  
the WATCHDOG service window and match the WATCH-  
>
1/tC 10 kHzNo clock rejection.  
<
1/tC 10 HzGuaranteed clock rejection.  
TABLE 10. WATCHDOG Service Actions  
Key  
Window  
Data  
Clock  
Monitor  
Match  
Action  
Data  
Match  
Match  
Valid Service: Restart Service Window  
Don’t Care  
Mismatch  
Don’t Care  
Mismatch  
Don’t Care  
Don’t Care  
Don’t Care Error: Generate WATCHDOG Output  
Don’t Care Error: Generate WATCHDOG Output  
Mismatch  
Error: Generate WATCHDOG Output  
14.3 WATCHDOG AND CLOCK MONITOR SUMMARY  
The initial WATCHDOG service must match the key data  
value in the WATCHDOG Service register WDSVR in  
order to avoid a WATCHDOG error.  
The following salient points regarding the WATCHDOG and  
CLOCK MONITOR should be noted:  
Subsequent WATCHDOG services must match all three  
data fields in WDSVR in order to avoid WATCHDOG  
errors.  
Both the WATCHDOG and CLOCK MONITOR detector  
circuits are inhibited during RESET.  
Following RESET, the WATCHDOG and CLOCK MONI-  
TOR are both enabled, with the WATCHDOG having the  
maximum service window selected.  
The correct key data value cannot be read from the  
WATCHDOG Service register WDSVR. Any attempt to  
read this key data value of 01100 from WDSVR will read  
as key data value of all 0’s.  
The WATCHDOG service window and CLOCK MONI-  
TOR enable/disable option can only be changed once,  
during the initial WATCHDOG service following RESET.  
The WATCHDOG detector circuit is inhibited during both  
the HALT and IDLE modes.  
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32  
This is an undefined ROM location and the instruction  
fetched (all 0’s) from this location will generate a software  
interrupt signaling an illegal condition.  
14.0 WATCHDOG/Clock Monitor  
(Continued)  
The CLOCK MONITOR detector circuit is active during  
both the HALT and IDLE modes. Consequently, the de-  
vice inadvertently entering the HALT mode will be de-  
tected as a CLOCK MONITOR error (provided that the  
CLOCK MONITOR enable option has been selected by  
the program).  
Thus, the chip can detect the following illegal conditions:  
1. Executing from undefined ROM  
2. Over “POP”ing the stack by having more returns than  
calls.  
When the software interrupt occurs, the user can re-initialize  
the stack pointer and do a recovery procedure before restart-  
ing (this recovery program is probably similar to that follow-  
ing reset, but might not contain the same program initializa-  
tion procedures). The recovery program should reset the  
software interrupt pending bit using the RPND instruction.  
With the single-pin R/C oscillator option selected and the  
CLKDLY bit reset, the WATCHDOG service window will  
resume following HALT mode from where it left off before  
entering the HALT mode.  
With the crystal oscillator option selected, or with the  
single-pin R/C oscillator option selected and the CLKDLY  
bit set, the WATCHDOG service window will be set to its  
selected value from WDSVR following HALT. Conse-  
quently, the WATCHDOG should not be serviced for at  
least 256 instruction cycles following HALT, but must be  
serviced within the selected window to avoid a WATCH-  
DOG error.  
15.0 MICROWIRE/PLUS  
MICROWIRE/PLUS is a serial SPI compatible synchronous  
communications interface. The MICROWIRE/PLUS capabil-  
ity enables the device to interface with MICROWIRE/PLUS  
or SPI peripherals (i.e. A/D converters, display drivers, EE-  
PROMs etc.) and with other microcontrollers which support  
the MICROWIRE/PLUS or SPI interface. It consists of an  
8-bit serial shift register (SIO) with serial data input (SI),  
serial data output (SO) and serial shift clock (SK). Figure 24  
shows a block diagram of the MICROWIRE/PLUS logic.  
The IDLE timer T0 is not initialized with external RESET.  
The user can sync in to the IDLE counter cycle with an  
IDLE counter (T0) interrupt or by monitoring the T0PND  
flag. The T0PND flag is set whenever the twelfth bit of the  
IDLE counter toggles (every 4096 instruction cycles). The  
user is responsible for resetting the T0PND flag.  
The shift clock can be selected from either an internal source  
or an external source. Operating the MICROWIRE/PLUS  
arrangement with the internal clock source is called the  
Master mode of operation. Similarly, operating the  
MICROWIRE/PLUS arrangement with an external shift clock  
is called the Slave mode of operation.  
A hardware WATCHDOG service occurs just as the de-  
vice exits the IDLE mode. Consequently, the WATCH-  
DOG should not be serviced for at least 256 instruction  
cycles following IDLE, but must be serviced within the  
selected window to avoid a WATCHDOG error.  
The CNTRL register is used to configure and control the  
MICROWIRE/PLUS mode. To use the MICROWIRE/PLUS,  
the MSEL bit in the CNTRL register is set to one. In the  
master mode, the SK clock rate is selected by the two bits,  
SL0 and SL1, in the CNTRL register. Table 11 details the  
different clock rates that may be selected.  
Following RESET, the initial WATCHDOG service (where  
the service window and the CLOCK MONITOR enable/  
disable must be selected) may be programmed any-  
where within the maximum service window (65,536 in-  
struction cycles) initialized by RESET. Note that this initial  
WATCHDOG service may be programmed within the ini-  
tial 256 instruction cycles without causing a WATCHDOG  
error.  
TABLE 11. MICROWIRE/PLUS  
Master Mode Clock Select  
In order to RESET the device on the occurrence of a  
WATCH event, the user must connect the WDOUT pin  
(G1) pin to the RESET external to the device. The weak  
pull-up on the WDOUT pin is sufficient to provide the  
RESET connection to VCC for devices which use both  
Power On Reset and WATCHDOG.  
SL1  
0
SL0  
SK Period  
0
1
x
2 x tC  
4 x tC  
8 x tC  
0
1
Where t is the instruction cycle clock  
C
14.4 DETECTION OF ILLEGAL CONDITIONS  
15.1 MICROWIRE/PLUS OPERATION  
The device can detect various illegal conditions resulting  
from coding errors, transient noise, power supply voltage  
drops, runaway programs, etc.  
Setting the BUSY bit in the PSW register causes the  
MICROWIRE/PLUS to start shifting the data. It gets reset  
when eight data bits have been shifted. The user may reset  
the BUSY bit by software to allow less than 8 bits to shift. If  
enabled, an interrupt is generated when eight data bits have  
been shifted. The device may enter the MICROWIRE/PLUS  
mode either as a Master or as a Slave. Figure 24 shows how  
two microcontroller devices and several peripherals may be  
interconnected using the MICROWIRE/PLUS arrangements.  
Reading of undefined ROM gets zeroes. The opcode for  
software interrupt is 00. If the program fetches instructions  
from undefined ROM, this will force a software interrupt, thus  
signaling that an illegal condition has occurred.  
The subroutine stack grows down for each call (jump to  
subroutine), interrupt, or PUSH, and grows up for each  
return or POP. The stack pointer is initialized to RAM location  
06F Hex during reset. Consequently, if there are more re-  
turns than calls, the stack pointer will point to addresses 070  
and 071 Hex (which are undefined RAM). Undefined RAM  
from addresses 070 to 07F (Segment 0), and all other seg-  
ments (i.e., Segments 4 … etc.) is read as all 1’s, which in  
turn will cause the program to return to address 7FFF Hex.  
WARNING  
The SIO register should only be loaded when the SK clock is  
in the idle phase. Loading the SIO register while the SK clock  
is in the active phase, will result in undefined data in the SIO  
register.  
Setting the BUSY flag when the input SK clock is in the  
active phase while in the MICROWIRE/PLUS is in the slave  
33  
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Master always initiates all data exchanges. The MSEL bit in  
the CNTRL register must be set to enable the SO and SK  
functions onto the G Port. The SO and SK pins must also be  
selected as outputs by setting appropriate bits in the Port G  
configuration register. In the slave mode, the shift clock  
stops after 8 clock pulses. Table 12 summarizes the bit  
settings required for Master mode of operation.  
15.0 MICROWIRE/PLUS (Continued)  
mode may cause the current SK clock for the SIO shift  
register to be narrow. For safety, the BUSY flag should only  
be set when the input SK clock is in the idle phase.  
15.2 MICROWIRE/PLUS MASTER MODE OPERATION  
In the MICROWIRE/PLUS Master mode of operation the  
shift clock (SK) is generated internally. The MICROWIRE  
20091737  
FIGURE 24. MICROWIRE/PLUS Application  
15.3 MICROWIRE/PLUS SLAVE MODE OPERATION  
Master is shifted properly. After eight clock pulses the BUSY  
flag is clear, the shift clock is stopped, and the sequence  
may be repeated.  
In the MICROWIRE/PLUS Slave mode of operation the SK  
clock is generated by an external source. Setting the MSEL  
bit in the CNTRL register enables the SO and SK functions  
onto the G Port. The SK pin must be selected as an input  
and the SO pin is selected as an output pin by setting and  
resetting the appropriate bits in the Port G configuration  
register. Table 12 summarizes the settings required to enter  
the Slave mode of operation.  
15.4 ALTERNATE SK PHASE OPERATION AND SK  
IDLE POLARITY  
The device allows either the normal SK clock or an alternate  
phase SK clock to shift data in and out of the SIO register. In  
both the modes the SK idle polarity can be either high or low.  
The polarity is selected by bit 5 of Port G data register. In the  
normal mode data is shifted in on the rising edge of the SK  
clock and the data is shifted out on the falling edge of the SK  
clock. The SIO register is shifted on each falling edge of the  
SK clock. In the alternate SK phase operation, data is shifted  
in on the falling edge of the SK clock and shifted out on the  
rising edge of the SK clock. Bit 6 of Port G configuration  
register selects the SK edge.  
This table assumes that the control flag MSEL is set.  
TABLE 12. MICROWIRE/PLUS Mode Settings  
G4 (SO)  
Config. Bit  
1
G5 (SK)  
Config. Bit  
1
G4  
Fun.  
SO  
G5  
Fun.  
Int.  
Operation  
MICROWIRE/PLUS  
Master  
SK  
A control flag, SKSEL, allows either the normal SK clock or  
the alternate SK clock to be selected. Resetting SKSEL  
causes the MICROWIRE/PLUS logic to be clocked from the  
normal SK signal. Setting the SKSEL flag selects the alter-  
nate SK clock. The SKSEL is mapped into the G6 configu-  
ration bit. The SKSEL flag will power up in the reset condi-  
tion, selecting the normal SK signal.  
0
1
0
1
0
0
TRI-  
STATE  
SO  
Int.  
MICROWIRE/PLUS  
Master  
SK  
Ext.  
SK  
MICROWIRE/PLUS  
Slave  
TRI-  
Ext.  
SK  
MICROWIRE/PLUS  
Slave  
STATE  
The user must set the BUSY flag immediately upon entering  
the Slave mode. This ensures that all data bits sent by the  
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34  
15.0 MICROWIRE/PLUS (Continued)  
TABLE 13. MICROWIRE/PLUS Shift Clock Polarity and Sample/Shift Phase  
Port G  
SK Idle  
Phase  
SK Phase  
G6 (SKSEL)  
G5  
SO Clocked Out On:  
SI Sampled On:  
Config. Bit  
Data Bit  
Normal  
Alternate  
Alternate  
Normal  
0
1
0
1
0
0
1
1
SK Falling Edge  
SK Rising Edge  
SK Rising Edge  
SK Falling Edge  
SK Rising Edge  
SK Falling Edge  
SK Falling Edge  
SK Rising Edge  
Low  
Low  
High  
High  
20091738  
FIGURE 25. MICROWIRE/PLUS SPI Mode Interface Timing, Normal SK Mode, SK Idle Phase being Low  
20091739  
FIGURE 26. MICROWIRE/PLUS SPI Mode Interface Timing, Alternate SK Mode, SK Idle Phase being Low  
20091740  
FIGURE 27. MICROWIRE/PLUS SPI Mode Interface Timing, Normal SK Mode, SK Idle Phase being High  
35  
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15.0 MICROWIRE/PLUS (Continued)  
20091741  
FIGURE 28. MICROWIRE/PLUS SPI Mode Interface Timing, Alternate SK Mode, SK Idle Phase being High  
The ACCESS.Bus protocol supports multiple master and  
16.0 ACCESS.Bus Interface  
slave transmitters and receivers. Each bus device has a  
The ACCESS.Bus interface module (ACB) is a two-wire  
unique address and can operate as a transmitter or a re-  
serial interface compatible with the ACCESS.Bus physical  
ceiver (though some peripherals are only receivers).  
layer. It permits easy interfacing to a wide range of low-cost  
memories and I/O devices, including: EEPROMs, SRAMs,  
16.1 DATA TRANSACTIONS  
timers, A/D converters, D/A converters, clock chips, and  
During data transactions, the master device initiates the  
peripheral drivers. It is compatible with Intel’s SMBus and  
transaction, generates the clock signal and terminates the  
Philips’ I2C bus. The module can be configured as a bus  
transaction. For example, when the ACB initiates a data  
master or slave, and can maintain bidirectional communica-  
transaction with an ACCESS.Bus peripheral, the ACB be-  
tions with both multiple master and multiple slave devices.  
comes the master. When the peripheral responds and trans-  
ACCESS.Bus master and slave  
mits data to the ACB, their master/slave (data transaction  
initiator and clock generator) relationship is unchanged,  
even though their transmitter/receiver functions are re-  
versed.  
Supports polling and interrupt-controlled operation  
Generate a wake-up signal on detection of a Start Con-  
dition, while in reduced-power mode  
One data bit is transferred during each clock period. Data is  
sampled during the high phase of the serial clock (SCL).  
Consequently, throughout the clock high phase, the data  
must remain stable (see Figure 29). Any change on the SDA  
signal during the high phase of the SCL clock and in the  
middle of a transaction aborts the current transaction. New  
data must be driven during the low phase of the SCL clock.  
This protocol permits a single data line to transfer both  
command/control information and data using the synchro-  
nous serial clock.  
Optional internal pull-up on SDA and SCL pins  
Optional 1.8V logic compatibility on SDA and SCL pins  
The ACCESS.Bus protocol uses a two-wire interface for  
bidirectional communication between the devices connected  
to the bus. The two interface signals are the Serial Data Line  
(SDA) and the Serial Clock Line (SCL). These signals should  
be connected to the positive supply, through pull-up resis-  
tors, to keep the signals high when the bus is idle. When the  
ACCESS.Bus module is enabled and Bit 7 of the Option  
Register (LVCMP) is set, the SDA and SCL inputs, along with  
input L2, provide compatibility with 1.8V logic levels.  
20091779  
FIGURE 29. Bit Transfer  
Each data transaction is composed of a Start Condition, a  
number of byte transfers (programmed by software) and a  
Stop Condition to terminate the transaction. Each byte is  
transferred with the most significant bit first, and after each  
byte, an Acknowledge signal must follow.  
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36  
16.1.1 Start and Stop  
16.0 ACCESS.Bus Interface  
The ACCESS.Bus master generates Start and Stop Condi-  
tions (control codes). After a Start Condition is generated,  
the bus is considered busy and it retains this status until a  
certain time after a Stop Condition is generated. A high-to-  
low transition of the data line (SDA) while the clock (SCL) is  
high indicates a Start Condition. A low-to-high transition of  
the SDA line while the SCL is high indicates a Stop Condition  
(Figure 30).  
(Continued)  
At each clock cycle, the slave can stall the master while it  
handles the previous data, or prepares new data. The slave  
can hold SCL low, to extend the clock-low period, on each bit  
transfer, or on a byte boundary, to accomplish this. Typically,  
slaves extend the first clock cycle of a transfer if a byte read  
has not yet been stored, or if the next byte to be transmitted  
is not yet ready. Some microcontrollers, with limited hard-  
ware support for ACCESS.Bus, extend the access after each  
bit, to allow software time to handle this bit.  
20091780  
FIGURE 30. Start and Stop Conditions  
In addition to the first Start Condition, a repeated Start  
Condition can be generated in the middle of a transaction.  
This allows another device to be accessed, or a change in  
the direction of the data transfer.  
arbitration. In master mode, the device immediately aborts a  
transaction if the value sampled on the SDA line differs from  
the value driven by the device.  
When an abort occurs during the address transmission, the  
master that identifies the conflict should give up the bus,  
switch to slave mode, and continue to sample SDA to see if  
it is being addressed by the winning master on the  
ACCESS.Bus.  
16.1.2 Acknowledge Cycle  
The Acknowledge Cycle consists of two signals: the ac-  
knowledge clock pulse the master sends with each byte  
transferred, and the acknowledge signal sent by the receiv-  
ing device.  
16.3 POWER SAVE MODES  
The master generates an acknowledge clock pulse after  
each byte transfer. The receiver sends an acknowledge  
signal after every byte received. There are two exceptions to  
the "acknowledge after every byte" rule.  
When this device is placed in HALT or IDLE mode, the ACB  
module is effectively disabled. Registers ACBST, ACBCST  
and ACBCTL1 are reset, however ACBSDA, ACBADDR and  
ACBCTL2 are unaffected. If the ACB is enabled  
(ACBCTL2.ENABLE = 1) on detection of a Start Condition, a  
wake-up signal is issued to the Multi-Input Wake-Up module.  
The byte transfer which causes the Wake-Up event will not  
be acknowledged by the COP8 ACCESS.Bus and thus must  
be retransmitted. The Multi-Input Wake-Up logic must be  
configured, by the user, to enable Wake-Up on ACCESS.Bus  
transfer. The ACCESS.Bus SDA signal is an alternate func-  
tion of the one of the Multi-Input Wake-Up pins, and thus the  
associated bit of the LWKEN or CWKEN and LWKEDG or  
CWKEDG registers must be configured to cause a Wake-Up  
event on a rising edge. See Figure 20 and the pinout table  
for determination of the Multi-Input Wake-Up channel asso-  
ciated with the ACCESS.Bus.  
When the master is the receiver, it must indicate to the  
transmitter an end-of-data condition by not-  
acknowledging ("negative acknowledge") the last byte  
clocked out of the slave. This "negative acknowledge"  
still includes the acknowledge clock pulse (generated by  
the master), but the SDA line is not pulled down.  
When the receiver is full, otherwise occupied, or a prob-  
lem has occurred, it sends a negative acknowledge to  
indicate that it cannot accept additional data bytes.  
16.1.3 Addressing Transfer Formats  
Each device on the bus has a unique address. Before any  
data is transmitted, the master transmits the address of the  
slave being addressed. The slave device should send an  
acknowledge signal on the SDA signal, once it recognizes its  
address.  
16.4 SDA AND SCL DRIVER CONFIGURATION  
SDA and SCL are driven as open-drain signals on Port L  
signals L0 and L1. If the ACB interface is not being used,  
these pins are available for use as general-purpose port pins  
or Multi-Input Wake-Up inputs.  
16.2 BUS ARBITRATION  
Arbitration is required when multiple master devices attempt  
to gain control of the bus simultaneously. Control of the bus  
is initially determined according to the address bits and clock  
cycle. If the masters are trying to address the same bus  
device, data comparisons determine the outcome of this  
37  
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16.0 ACCESS.Bus Interface  
TGSCL  
TSDA  
The Toggle SCL bit enables toggling the SCL  
signal during error recovery. When the SDA  
signal is low, writing 1 to this bit drives the  
SCL signal high for one cycle. Writing 1 to  
TGSCL when the SDA signal is high is  
ignored.  
(Continued)  
16.5 ACB SERIAL DATA REGISTER (ACBSDA)  
The ACBSDA register is a byte-wide, read/write shift register  
used to transmit and receive data. The most significant bit is  
transmitted (received) first and the least significant bit is  
transmitted (received) last.  
The Test SDA bit samples the state of the  
SDA signal. This bit can be used while  
recovering from an error condition in which  
the SDA signal is constantly pulled low by a  
slave that has lost synchronization. This bit is  
a read-only bit.  
7
0
DATA  
16.6 ACB STATUS REGISTER (ACBST)  
The ACBST register is a byte-wide, read-only register that  
reports the current ACB status.  
GCMTCH The Global Call Match bit is set in slave  
mode when the ACBCTL1.GCMEN bit is set  
and the address byte (the first byte  
7
6
5
4
3
2
1
0
SLVSTP SDAST BER NEGACK RSVD NMATCH MASTER XMIT  
transferred after a Start Condition) is 00.  
MATCH  
The Address Match bit indicates in slave  
mode when ACBADDR.SAEN is set and the  
first seven bits of the address byte (the first  
byte transferred after a Start Condition)  
matches the 7-bit address in the ACBADDR  
register.  
SLVSTP  
SDAST  
BER  
The Slave Stop bit is set when a Stop  
Condition was detected after a slave transfer  
(i.e., after a slave transfer in which MATCH  
or GCMTCH is set).  
The SDA Status bit is set when the SDA  
data register is waiting for data (transmit, as  
master or slave) or holds data that should be  
read (receive, as master or slave)  
BB  
The Bus Busy bit indicates the bus is busy. It  
is set when the bus is active (i.e., a low level  
on either SDA or SCL) or by a Start  
Condition. It is cleared when the module is  
disabled or a Stop Condition is detected.  
The BUSY bit indicates that the ACB module  
is:  
The Bus Error bit is set when a Start or Stop  
Condition is detected during data transfer or  
when an arbitration problem is detected.  
BUSY  
NEGACK The Negative Acknowledge bit is set when a  
transmission is not acknowledged.  
Generating a Start Condition  
RSVD  
This bit is reserved and will be zero.  
In Master mode (ACBST.MASTER is set)  
NMATCH The New Match bit is set when the address  
byte following a Start Condition, or repeated  
starts, causes a match or a global-call  
match.  
In Slave mode (ACBCST.MATCH or  
ACBCST.GCMTCH is set)  
In the period between detecting a Start and  
completing the reception of the address  
byte. After this, the ACB either becomes  
not busy or enters slave mode. The BUSY  
bit is cleared by the completion of any of  
the above states, or by disabling the  
module. BUSY is a read only bit.  
MASTER The Master bit indicates that the module is  
currently in master mode. It is set when a  
request for bus mastership succeeds. It is  
cleared upon arbitration loss (BER is set) or  
the recognition of a Stop Condition.  
XMIT  
The Direction bit is set when the ACB  
module is currently in master/slave transmit  
mode. Otherwise, it is clear.  
16.8 ACB CONTROL 1 REGISTER (ACBCTL1)  
The ACBCTL1 register is a byte-wide, read/write register  
that configures and controls the ACB module. At reset and  
while the module is disabled (ACBCTL2.ENABLE = 0), the  
ACBCTL1 register is cleared.  
16.7 ACB CONTROL STATUS REGISTER (ACBCST)  
The ACBCST register is a byte-wide, read/write register that  
reports the current ACB status. At reset and when the mod-  
ule is disabled, the non-reserved bits of ACBCST are  
cleared.  
7
6
5
4
3
2
1
0
CLRST NMINTE GCMEN ACK RSVD INTEN STOP START  
CLRST  
The Clear Status bit clears the NMATCH,  
BER, NEGACK and SLVSTP bits when 1 is  
written to this bit.  
7
6
5
4
3
2
1
0
RSVD  
TGSCL  
TSDA GCMTCH MATCH BB BUSY  
NMINTE  
The New Match Interrupt Enable controls  
whether ACB interrupts are generated on  
new matches.  
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38  
16.0 ACCESS.Bus Interface  
ENABLE  
The Enable bit controls the ACB  
module. When this bit is set, the ACB  
module is enabled. When the Enable  
bit is clear, the ACB module is  
(Continued)  
GCMEN  
The Global Call Match Enable bit enables  
the match of an incoming address byte to  
the general call address (Start Condition  
followed by address byte of 00) while the  
ACB is in slave mode.  
disabled, the ACBCTL1, ACBST, and  
ACBCST registers are cleared, and the  
ACB module clocks are halted.  
ACK  
The Acknowledge bit holds the value this  
device sends in master or slave mode during  
the next acknowledge cycle. Setting this bit  
to 1 instructs the transmitting device to stop  
sending data, because the receiver either  
does not need, or cannot receive, any more  
data.  
16.10 ACB OWN ADDRESS REGISTER (ACBADDR)  
The ACBADDR register is a byte-wide, read/write register  
that holds the module’s first ACCESS.Bus address.  
7
6
0
SEAN  
ADDR  
SAEN  
The Slave Address Enable bit controls  
whether address matching is performed  
in slave mode. When set, the SAEN bit  
indicates that the ADDR field holds a  
valid address and enables the match of  
ADDR to an incoming address byte.  
The Own Address field holds the 7-bit  
ACCESS.Bus address of this device. In  
slave mode, the 7 bits received after a  
Start Condition are compared to this field  
(first bit received to bit 6, and the last to  
bit 0). If the address field matches the  
received data and the SAEN bit is set, a  
match is detected.  
INTEN  
The Interrupt Enable bit controls generating  
ACB interrupts. When the INTEN bit is set,  
interrupts are enabled. An interrupt is  
generated on any of the following events:  
An address MATCH is detected  
(ACBST.NMATCH = 1) and the NMINTE  
bit is set.  
ADDR  
A Bus Error occurs (ACBST.BERR = 1).  
Negative acknowledge after sending  
byte (ACBST.NEGACK = 1).  
a
An interrupt is generated on acknowledge  
of each transaction (same as hardware  
setting the ACBST.SDAST bit).  
Detection of a Stop Condition while in  
slave receive mode (ACBST.SLVSTP =  
1).  
17.0 Memory Map  
All RAM, ports and registers (except A and PC) are mapped  
into data memory address space.  
STOP  
The Stop bit in master mode generates a  
Stop Condition that completes or aborts the  
current message transfer.  
Address  
Contents  
ADD REG  
START  
The Start bit is set to generate a Start  
Condition on the ACCESS.Bus. This bit  
should be set only when in Master mode or  
when requesting Master mode. An address  
send sequence should then be performed.  
00 to 6F  
70 to 7F  
On-Chip RAM bytes (112 bytes)  
Unused RAM Address Space (Reads As  
All Ones)  
80 to 83  
84  
Unused RAM Address Space (Reads  
Undefined Data)  
16.9 ACB CONTROL REGISTER 2 (ACBCTL2)  
Port C MIWU Edge Select Register  
(Reg: CWKEDG)  
The ACBCTL2 register is a byte-wide, read/write register  
that controls the module and selects the ACB clock rate. At  
reset, the ACBCTL2 register is cleared.  
85  
Port C MIWU Enable Register (Reg:  
CWKEN)  
7
1
0
86  
Port C MIWU Pending Register (Reg:  
CWKPND)  
SCLFRQ  
ENABLE  
SCLFRQ  
The SCL Frequency field specifies the  
SCL period (low time and high time) in  
master mode. The clock low time and  
high time are defined as follows:  
tSCLK1 = tSCLKh = 2 x SCLFRQ x tSCLK  
Where tCLK is this device’s clock  
period when in Active mode. The  
SCLFRQ field may be programmed to  
values in the range of 0001000  
through 1111111.  
87 to 8F  
90 to 93  
94  
Reserved  
Reserved  
Port F Data Register  
95  
Port F Configuration Register  
Port F Input pins (Read Only)  
Reserved for Port F  
96  
97  
98 to AF  
B0 to B7  
B8  
Reserved  
Reserved  
ACB Serial Data Register (ACBSDA)  
39  
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17.0 Memory Map (Continued)  
Address  
Contents  
ADD REG  
Address  
Contents  
ADD REG  
FC  
X Register  
SP Register  
B Register  
FD  
FE  
FF  
B9  
ACB Status Register (ACBST)  
ACB Control And Status (ACBCST)  
ACB Control Register 1 (ACBCTL1)  
ACB Own Address Register (ACBADDR)  
ACB Control Register 2(ACBCTL2)  
Reserved  
BA  
On-Chip RAM Mapped as Register  
BB  
Note: Reading memory locations 70H–7FH will return all ones. Reading  
unused memory locations 80H–83H, 87H–93H will return undefined  
data.  
BC  
BD  
BE to BF  
C0 to C6  
C7  
18.0 Instruction Set  
Reserved  
WATCHDOG Service Register  
(Reg:WDSVR)  
18.1 INTRODUCTION  
This section defines the instruction set of the COP8 Family  
members. It contains information about the instruction set  
features, addressing modes and types.  
C8  
C9  
CA  
Port L MIWU Edge Select Register  
(Reg:LWKEDG)  
Port L MIWU Enable Register  
(Reg:LWKEN)  
18.2 INSTRUCTION FEATURES  
The strength of the instruction set is based on the following  
features:  
Port L MIWU Pending Register  
(Reg:LWKPND)  
Mostly single-byte opcode instructions minimize program  
size.  
CB to CE  
CF  
Reserved  
Idle Timer Control Register (ITMR)  
Port L Data Register  
One instruction cycle for the majority of single-byte in-  
structions to minimize program execution time.  
D0  
Many single-byte, multiple function instructions such as  
DRSZ.  
D1  
Port L Configuration Register  
Port L Input Pins (Read Only)  
Reserved for Port L  
D2  
Three memory mapped pointers: two for register indirect  
addressing, and one for the software stack.  
D3  
D4  
Port G Data Register  
Sixteen memory mapped registers that allow an opti-  
mized implementation of certain instructions.  
D5  
Port G Configuration Register  
Port G Input Pins (Read Only)  
Reserved  
D6  
Ability to set, reset, and test any individual bit in data  
memory address space, including the memory-mapped  
I/O ports and registers.  
D7  
D8  
Port C Data Register  
Register-Indirect LOAD and EXCHANGE instructions  
with optional automatic post-incrementing or decrement-  
ing of the register pointer. This allows for greater effi-  
ciency (both in cycle time and program code) in loading,  
walking across and processing fields in data memory.  
D9  
Port C Configuration Register  
Port C Input Pins (Read Only)  
Reserved  
DA  
DB  
DC  
Port J Data Register  
Unique instructions to optimize program size and  
throughput efficiency. Some of these instructions are:  
DRSZ, IFBNE, DCOR, RETSK, VIS and RRC.  
DD  
Port J Configuration Register  
Port J Input Pins (Read Only)  
CPU Clock Prescale Register (CLKPS)  
Reserved  
DE  
DF  
18.3 ADDRESSING MODES  
E0 to E5  
E6  
The instruction set offers a variety of methods for specifying  
memory addresses. Each method is called an addressing  
mode. These modes are classified into two categories: op-  
erand addressing modes and transfer-of-control addressing  
modes. Operand addressing modes are the various meth-  
ods of specifying an address for accessing (reading or writ-  
ing) data. Transfer-of-control addressing modes are used in  
conjunction with jump instructions to control the execution  
sequence of the software program.  
Timer T1 Autoload Register T1RB Lower  
Byte  
E7  
Timer T1 Autoload Register T1RB Upper  
Byte  
E8  
E9  
EA  
EB  
EC  
ICNTRL Register  
MICROWIRE/PLUS Shift Register  
Timer T1 Lower Byte  
Timer T1 Upper Byte  
18.3.1 Operand Addressing Modes  
Timer T1 Autoload Register T1RA Lower  
Byte  
The operand of an instruction specifies what memory loca-  
tion is to be affected by that instruction. Several different  
operand addressing modes are available, allowing memory  
locations to be specified in a variety of ways. An instruction  
can specify an address directly by supplying the specific  
address, or indirectly by specifying a register pointer. The  
contents of the register (or in some cases, two registers)  
ED  
Timer T1 Autoload Register T1RA Upper  
Byte  
EE  
CNTRL Control Register  
PSW Register  
EF  
F0 to FB  
On-Chip RAM Mapped as Registers  
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40  
18.0 Instruction Set (Continued)  
point to the desired memory location. In the immediate  
mode, the data byte to be used is contained in the instruction  
itself.  
Reg/Data  
Memory  
Contents  
Before  
Contents  
After  
Accumulator  
Memory Location  
0005 Hex  
03 Hex  
62 Hex  
62 Hex  
05 Hex  
03 Hex  
06 Hex  
Each addressing mode has its own advantages and disad-  
vantages with respect to flexibility, execution speed, and  
program compactness. Not all modes are available with all  
instructions. The Load (LD) instruction offers the largest  
number of addressing modes.  
B Pointer  
Intermediate. The data for the operation follows the instruc-  
tion opcode in program memory. In assembly language, the  
number sign character (#) indicates an immediate operand.  
The available addressing modes are:  
Direct  
Example: Load Accumulator Immediate  
LD A,#05  
Register B or X Indirect  
Register  
Decrementing  
B or X Indirect with Post-Incrementing/  
Reg/Data  
Memory  
Contents  
Before  
Contents  
After  
Immediate  
Accumulator  
XX Hex  
05 Hex  
Immediate Short  
Indirect from Program Memory  
Immediate Short. This is a special case of an immediate  
instruction. In the “Load B immediate” instruction, the 4-bit  
immediate value in the instruction is loaded into the lower  
nibble of the B register. The upper nibble of the B register is  
reset to 0000 binary.  
The addressing modes are described below. Each descrip-  
tion includes an example of an assembly language instruc-  
tion using the described addressing mode.  
Direct. The memory address is specified directly as a byte in  
the instruction. In assembly language, the direct address is  
written as a numerical value (or a label that has been defined  
elsewhere in the program as a numerical value).  
Example: Load B Register Immediate Short  
LD B,#7  
Reg/Data  
Memory  
B Pointer  
Contents  
Before  
Contents  
After  
Example: Load Accumulator Memory Direct  
LD A,05  
12 Hex  
07 Hex  
Reg/Data  
Memory  
Contents  
Before  
Contents  
After  
Indirect from Program Memory. This is a special case of  
an indirect instruction that allows access to data tables  
stored in program memory. In the “Load Accumulator Indi-  
rect” (LAID) instruction, the upper and lower bytes of the  
Program Counter (PCU and PCL) are used temporarily as a  
pointer to program memory. For purposes of accessing pro-  
gram memory, the contents of the Accumulator and PCL are  
exchanged. The data pointed to by the Program Counter is  
loaded into the Accumulator, and simultaneously, the original  
contents of PCL are restored so that the program can re-  
sume normal execution.  
Accumulator  
Memory Location  
0005 Hex  
XX Hex  
A6 Hex  
A6 Hex  
A6 Hex  
Register B or X Indirect. The memory address is specified  
by the contents of the B Register or X register (pointer  
register). In assembly language, the notation [B] or [X] speci-  
fies which register serves as the pointer.  
Example: Exchange Memory with Accumulator, B Indirect  
X A,[B]  
Example: Load Accumulator Indirect  
LAID  
Reg/Data  
Memory  
Contents  
Before  
Contents  
After  
Reg/Data  
Memory  
Contents  
Before  
04 Hex  
35 Hex  
1F Hex  
Contents  
After  
Accumulator  
Memory Location  
0005 Hex  
01 Hex  
87 Hex  
PCU  
04 Hex  
36 Hex  
25 Hex  
87 Hex  
05 Hex  
01 Hex  
05 Hex  
PCL  
Accumulator  
Memory Location  
041F Hex  
B Pointer  
25 Hex  
25 Hex  
Register  
B or X Indirect with Post-Incrementing/  
Decrementing. The relevant memory address is specified  
by the contents of the B Register or X register (pointer  
register). The pointer register is automatically incremented  
or decremented after execution, allowing easy manipulation  
of memory blocks with software loops. In assembly lan-  
guage, the notation [B+], [B−], [X+], or [X−] specifies which  
register serves as the pointer, and whether the pointer is to  
be incremented or decremented.  
18.3.2 Tranfer-of-Control Addressing Modes  
Program instructions are usually executed in sequential or-  
der. However, Jump instructions can be used to change the  
normal execution sequence. Several transfer-of-control ad-  
dressing modes are available to specify jump addresses.  
A change in program flow requires a non-incremental  
change in the Program Counter contents. The Program  
Counter consists of two bytes, designated the upper byte  
(PCU) and lower byte (PCL). The most significant bit of PCU  
is not used, leaving 15 bits to address the program memory.  
Example: Exchange Memory with Accumulator, B Indirect  
with Post-Increment  
X A,[B+]  
41  
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Example: Jump Indirect  
JID  
18.0 Instruction Set (Continued)  
Different addressing modes are used to specify the new  
address for the Program Counter. The choice of addressing  
mode depends primarily on the distance of the jump. Farther  
jumps sometimes require more instruction bytes in order to  
completely specify the new Program Counter contents.  
Reg/  
Memory  
PCU  
Contents  
Before  
01 Hex  
C4 Hex  
26 Hex  
Contents  
After  
01 Hex  
32 Hex  
26 Hex  
PCL  
The available transfer-of-control addressing modes are:  
Accumulator  
Memory  
Location  
0126 Hex  
Jump Relative  
Jump Absolute  
Jump Absolute Long  
Jump Indirect  
32 Hex  
32 Hex  
The transfer-of-control addressing modes are described be-  
low. Each description includes an example of a Jump in-  
struction using a particular addressing mode, and the effect  
on the Program Counter bytes of executing that instruction.  
The VIS instruction is a special case of the Indirect Transfer  
of Control addressing mode, where the double-byte vector  
associated with the interrupt is transferred from adjacent  
addresses in program memory into the Program Counter in  
order to jump to the associated interrupt service routine.  
Jump Relative. In this 1-byte instruction, six bits of the  
instruction opcode specify the distance of the jump from the  
current program memory location. The distance of the jump  
can range from −31 to +32. A JP+1 instruction is not allowed.  
The programmer should use a NOP instead.  
18.4 INSTRUCTION TYPES  
The instruction set contains a wide variety of instructions.  
The available instructions are listed below, organized into  
related groups.  
Example: Jump Relative  
JP 0A  
Some instructions test a condition and skip the next instruc-  
tion if the condition is not true. Skipped instructions are  
executed as no-operation (NOP) instructions.  
Contents  
Before  
Contents  
After  
Reg  
18.4.1 Arithmetic Instructions  
PCU  
PCL  
02 Hex  
05 Hex  
02 Hex  
0F Hex  
The arithmetic instructions perform binary arithmetic such as  
addition and subtraction, with or without the Carry bit.  
Jump Absolute. In this 2-byte instruction, 12 bits of the  
instruction opcode specify the new contents of the Program  
Counter. The upper three bits of the Program Counter re-  
main unchanged, restricting the new Program Counter ad-  
dress to the same 4-kbyte address space as the current  
instruction. (This restriction is relevant only in devices using  
more than one 4-kbyte program memory space.)  
Add (ADD)  
Add with Carry (ADC)  
Subtract with Carry (SUBC)  
Increment (INC)  
Decrement (DEC)  
Decimal Correct (DCOR)  
Clear Accumulator (CLR)  
Set Carry (SC)  
Example: Jump Absolute  
JMP 0125  
Reset Carry (RC)  
Contents  
Before  
Contents  
After  
Reg  
18.4.2 Transfer-of-Control Instructions  
PCU  
PCL  
0C Hex  
77 Hex  
01 Hex  
25 Hex  
The transfer-of-control instructions change the usual se-  
quential program flow by altering the contents of the Pro-  
gram Counter. The Jump to Subroutine instructions save the  
Program Counter contents on the stack before jumping; the  
Return instructions pop the top of the stack back into the  
Program Counter.  
Jump Absolute Long. In this 3-byte instruction, 15 bits of  
the instruction opcode specify the new contents of the Pro-  
gram Counter.  
Example: Jump Absolute Long  
JMP 03625  
Jump Relative (JP)  
Jump Absolute (JMP)  
Reg/  
Memory  
PCU  
Contents  
Before  
Contents  
After  
Jump Absolute Long (JMPL)  
Jump Indirect (JID)  
42 Hex  
36 Hex  
36 Hex  
25 Hex  
Jump to Subroutine (JSR)  
Jump to Subroutine Long (JSRL)  
Return from Subroutine (RET)  
Return from Subroutine and Skip (RETSK)  
Return from Interrupt (RETI)  
Software Trap Interrupt (INTR)  
Vector Interrupt Select (VIS)  
PCL  
Jump Indirect. In this 1-byte instruction, the lower byte of  
the jump address is obtained from a table stored in program  
memory, with the Accumulator serving as the low order byte  
of a pointer into program memory. For purposes of access-  
ing program memory, the contents of the Accumulator are  
written to PCL (temporarily). The data pointed to by the  
Program Counter (PCH/PCL) is loaded into PCL, while PCH  
remains unchanged.  
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42  
Decrement Register and Skip if Zero (DRSZ)  
18.0 Instruction Set (Continued)  
18.4.9 No-Operation Instruction  
18.4.3 Load and Exchange Instructions  
The no-operation instruction does nothing, except to occupy  
space in the program memory and time in execution.  
The load and exchange instructions write byte values in  
registers or memory. The addressing mode determines the  
source of the data.  
No-Operation (NOP)  
Load (LD)  
Note: The VIS is a special case of the Indirect Transfer of  
Control addressing mode, where the double byte vector  
associated with the interrupt is transferred from adjacent  
addresses in the program memory into the program counter  
(PC) in order to jump to the associated interrupt service  
routine.  
Load Accumulator Indirect (LAID)  
Exchange (X)  
18.4.4 Logical Instructions  
The logical instructions perform the operations AND, OR,  
and XOR (Exclusive OR). Other logical operations can be  
performed by combining these basic operations. For ex-  
ample, complementing is accomplished by exclusive-ORing  
the Accumulator with FF Hex.  
18.5 REGISTER AND SYMBOL DEFINITION  
The following abbreviations represent the nomenclature  
used in the instruction description and the COP8 cross-  
assembler.  
Logical AND (AND)  
Logical OR (OR)  
Registers  
A
8-Bit Accumulator Register  
8-Bit Address Register  
Exclusive OR (XOR)  
B
18.4.5 Accumulator Bit Manipulation Instructions  
X
8-Bit Address Register  
The Accumulator bit manipulation instructions allow the user  
to shift the Accumulator bits and to swap its two nibbles.  
S
8-Bit Segment Register  
SP  
PC  
PU  
PL  
C
8-Bit Stack Pointer Register  
15-Bit Program Counter Register  
Upper 7 Bits of PC  
Rotate Right Through Carry (RRC)  
Rotate Left Through Carry (RLC)  
Swap Nibbles of Accumulator (SWAP)  
Lower 8 Bits of PC  
18.4.6 Stack Control Instructions  
Push Data onto Stack (PUSH)  
Pop Data off of Stack (POP)  
1 Bit of PSW Register for Carry  
1 Bit of PSW Register for Half Carry  
1 Bit of PSW Register for Global Interrupt  
Enable  
HC  
GIE  
18.4.7 Memory Bit Manipulation Instructions  
VU  
VL  
Interrupt Vector Upper Byte  
Interrupt Vector Lower Byte  
The memory bit manipulation instructions allow the user to  
set and reset individual bits in memory.  
Set Bit (SBIT)  
Symbols  
Reset Bit (RBIT)  
[B]  
Memory Indirectly Addressed by B Register  
Memory Indirectly Addressed by X Register  
Direct Addressed Memory  
Direct Addressed Memory or [B]  
Direct Addressed Memory or [B] or  
Immediate Data  
Reset Pending Bit (RPND)  
[X]  
18.4.8 Conditional Instructions  
MD  
The conditional instruction test a condition. If the condition is  
true, the next instruction is executed in the normal manner; if  
the condition is false, the next instruction is skipped.  
Mem  
Meml  
If Equal (IFEQ)  
Imm  
Reg  
8-Bit Immediate Data  
If Not Equal (IFNE)  
If Greater Than (IFGT)  
If Carry (IFC)  
Register Memory: Addresses F0 to FF  
(Includes B, X and SP)  
Bit  
Bit Number (0 to 7)  
If Not Carry (IFNC)  
If Bit (IFBIT)  
Loaded with  
Exchanged with  
If B Pointer Not Equal (IFBNE)  
And Skip if Zero (ANDSZ)  
43  
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18.0 Instruction Set (Continued)  
18.6 INSTRUCTION SET SUMMARY  
ADD  
ADC  
A,Meml  
A,Meml  
ADD  
A
A
A + Meml  
A + Meml + C, C Carry,  
ADD with Carry  
HC Half Carry  
← ←  
A − MemI + C, C Carry,  
SUBC  
A,Meml  
Subtract with Carry  
A
HC Half Carry  
AND  
A,Meml  
Logical AND  
A
A and Meml  
Skip next if (A and Imm) = 0  
ANDSZ A,Imm  
Logical AND Immed., Skip if Zero  
Logical OR  
OR  
A,Meml  
A,Meml  
MD,Imm  
A,Meml  
A,Meml  
A,Meml  
#
A
A
A or Meml  
XOR  
IFEQ  
IFEQ  
IFNE  
IFGT  
IFBNE  
DRSZ  
SBIT  
RBIT  
IFBIT  
RPND  
X
Logical EXclusive OR  
IF EQual  
A xor Meml  
Compare MD and Imm, Do next if MD = Imm  
Compare A and Meml, Do next if A = Meml  
IF EQual  
Compare A and Meml, Do next if A Meml  
>
Compare A and Meml, Do next if A Meml  
Do next if lower 4 bits of B Imm  
IF Not Equal  
IF Greater Than  
If B Not Equal  
Reg  
Decrement Reg., Skip if Zero  
Set BIT  
Reg Reg − 1, Skip if Reg = 0  
#,Mem  
#,Mem  
#,Mem  
1 to bit, Mem (bit = 0 to 7 immediate)  
0 to bit, Mem  
Reset BIT  
IF BIT  
If bit #,A or Mem is true do next instruction  
Reset Software Interrupt Pending Flag  
Reset PeNDing Flag  
EXchange A with Memory  
EXchange A with Memory [X]  
LoaD A with Memory  
LoaD A with Memory [X]  
LoaD B with Immed.  
LoaD Memory Immed.  
LoaD Register Memory Immed.  
EXchange A with Memory [B]  
EXchange A with Memory [X]  
LoaD A with Memory [B]  
LoaD A with Memory [X]  
LoaD Memory [B] Immed.  
CLeaR A  
A,Mem  
A,[X]  
A
A
A
A
B
Mem  
[X]  
X
LD  
A,Meml  
A,[X]  
Meml  
[X]  
LD  
LD  
B,Imm  
Mem,Imm  
Reg,Imm  
A, [B ]  
A, [X ]  
A, [B ]  
A, [X ]  
[B ],Imm  
A
Imm  
Mem Imm  
LD  
Reg Imm  
LD  
[B], (B B 1)  
X
A
A
A
A
[X], (X X 1)  
X
[B], (B B 1)  
LD  
[X], (X X 1)  
LD  
← ←  
[B] Imm, (B B 1)  
LD  
A
A
A
A
A
C
C
CLR  
INC  
DEC  
LAID  
DCOR  
RRC  
RLC  
SWAP  
SC  
0
A
INCrement A  
A + 1  
A
DECrement A  
A − 1  
Load A InDirect from ROM  
Decimal CORrect A  
Rotate A Right thru C  
Rotate A Left thru C  
SWAP nibbles of A  
Set C  
ROM (PU,A)  
A
A
A
A
BCD correction of A (follows ADC, SUBC)  
A0 C  
A7  
A7  
A0 C, HC A0  
A7…A4 A3…A0  
C
C
1, HC  
0, HC  
1
0
RC  
Reset C  
IFC  
IF C  
IF C is true, do next instruction  
IFNC  
POP  
PUSH  
VIS  
IF Not C  
If C is not true, do next instruction  
← ←  
SP SP + 1, A [SP]  
A
A
POP the stack into A  
PUSH A onto the stack  
Vector to Interrupt Service Routine  
Jump absolute Long  
Jump absolute  
[SP] A, SP SP − 1  
PU [VU], PL [VL]  
PC ii (ii = 15 bits, 0 to 32k)  
JMPL  
JMP  
JP  
Addr.  
Addr.  
Disp.  
PC9…0 i (i = 12 bits)  
PC PC + r (r is −31 to +32, except 1)  
Jump relative short  
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44  
18.0 Instruction Set (Continued)  
← ← ←  
[SP] PL, [SP−1] PU,SP−2, PC ii  
JSRL  
JSR  
Addr.  
Addr.  
Jump SubRoutine Long  
Jump SubRoutine  
Jump InDirect  
[SP] PL, [SP−1] PU,SP−2, PC9…0 i  
PL ROM (PU,A)  
JID  
← ←  
SP + 2, PL [SP], PU [SP−1]  
RET  
RETurn from subroutine  
RETurn and SKip  
RETSK  
SP + 2, PL [SP],PU [SP−1],  
skip next instruction  
RETI  
INTR  
NOP  
RETurn from Interrupt  
Generate an Interrupt  
No OPeration  
SP + 2, PL [SP],PU [SP−1],GIE 1  
[SP] PL, [SP−1] PU, SP−2, PC 0FF  
PC PC + 1  
18.7 INSTRUCTION EXECUTION TIME  
Instructions Using A & C  
Most instructions are single byte (with immediate addressing  
mode instructions taking two bytes).  
CLRA  
INCA  
DECA  
LAID  
1/1  
1/1  
1/1  
1/3  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/3  
1/3  
2/2  
Most single byte instructions take one cycle time to execute.  
Skipped instructions require x number of cycles to be  
skipped, where x equals the number of bytes in the skipped  
instruction opcode.  
DCORA  
RRCA  
RLCA  
SWAPA  
SC  
See the BYTES and CYCLES per INSTRUCTION table for  
details.  
Bytes and Cycles per Instruction  
The following table shows the number of bytes and cycles for  
each instruction in the format of byte/cycle.  
RC  
Arithmetic and Logic Instructions  
IFC  
[B]  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
Direct  
3/4  
Immed.  
2/2  
IFNC  
ADD  
ADC  
SUBC  
AND  
OR  
PUSHA  
POPA  
ANDSZ  
3/4  
2/2  
3/4  
2/2  
3/4  
2/2  
Transfer of Control Instructions  
3/4  
2/2  
XOR  
IFEQ  
IFGT  
IFBNE  
DRSZ  
SBIT  
RBIT  
IFBIT  
3/4  
2/2  
JMPL  
JMP  
JP  
3/4  
2/3  
1/3  
3/5  
2/5  
1/3  
1/5  
1/5  
1/5  
1/5  
1/7  
1/1  
3/4  
2/2  
3/4  
2/2  
JSRL  
JSR  
1/3  
3/4  
3/4  
3/4  
1/1  
1/1  
1/1  
JID  
VIS  
RET  
RETSK  
RETI  
INTR  
NOP  
RPND  
1/1  
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18.0 Instruction Set (Continued)  
Memory Transfer Instructions  
Register Indirect  
Auto Incr. & Decr.  
[B+, B−] [X+, X−]  
1/2 1/3  
1/3  
Register  
Indirect  
Direct Immed.  
[B]  
1/1  
1/1  
[X]  
1/3  
1/3  
X A, (Note 8)  
LD A, (Note 8)  
LD B,Imm  
2/3  
2/3  
2/2  
1/1  
2/2  
1/2  
<
(If B 16)  
>
(If B 15)  
LD B,Imm  
LD Mem,Imm  
LD Reg,Imm  
IFEQ MD,Imm  
2/2  
3/3  
2/3  
3/3  
2/2  
>
Memory location addressed by B or X or directly.  
Note 8:  
=
www.national.com  
46  
N i b b l e L o w e r  
47  
www.national.com  
19.0 Development Support  
19.1 TOOLS ORDERING NUMBERS FOR THE COP8TA 2.5V FAMILY DEVICES  
This section provides specific tools ordering information for the devices in this datasheet, followed by a summary of the tools and  
development kits available at print time. Up-to-date information, device selection guides, demos, updates, and purchase  
information can be obtained at our web site at: www.national.com/cop8.  
Unless otherwise noted, tools can be purchased for worldwide delivery from National’s e-store: http://www.national.com/  
store/  
Tool  
Order Number  
Cost*  
Free  
Notes/Includes  
Evaluation Software and Reference Designs  
Software and Utilities  
Web Downloads:  
Assembler/ Linker/ Simulators/ Library Manager/  
Compiler Demos/ Flash ISP and NiceMon Debugger  
Utilities/ Example Code/ etc.  
www.national.com/cop8  
(Flash Emulator support requires licensed COP8-NSDEV  
CD-ROM).  
Hardware Reference  
Designs  
None  
Starter Kits and Hardware Target Boards  
Starter Development  
Kits  
COP8-DB-TAC  
L
Supports COP8TA - Target board with 44LLP and 28SOIC  
sockets, LEDs, Test Points, and Breadboard Area.  
Development CD, ISP Cable and Source Code. No p/s.  
Also supports COP8 Low Voltage Flash Emulator and  
Kanda ISP Tool.  
Software Development Languages, and Integrated Development Environments  
National’s WCOP8 IDE COP8-NSDEV  
and Assembler on CD  
Fully Licensed IDE with Assembler and  
Emulator/Debugger Support. Assembler/ Linker/  
Simulator/ Utilities/ Documentation. Updates from web.  
Included with COP8-DB-TAC, SKFlash, COP8 Emulators.  
The ultimate information source for COP8 developers -  
Integrates with WCOP8 IDE. Organize and manage code,  
notes, datasheets, etc.  
COP8 Library Manager www.kkd.dk/libman.htm  
from KKD  
Eval  
M
Hardware Emulation and Debug Tools  
Hardware Emulators  
COP8-IMFlash-LV  
Includes 110v/220v p/s, target cable with 2x7 connector,  
manuals and software on CD.  
Development and Production Programming Tools  
Programming Adapters COP8-PGMA-20SF2  
L
L
L
L
For programming 20SOIC COP8TA only.  
For programming 28SOIC COP8TA only.  
For programming 44LLP COP8TAC only.  
(For any programmer  
COP8-PGMA-28SF2  
supporting flash adapter  
COP8-PGMA-44CF2  
base pinout)  
KANDA’s Flash ISP  
Programmer  
COP8 USB ISP  
www.kanda.com  
USB connected Dongle, with target cable and Control  
Software; Updateable from the web; Purchase from  
www.kanda.com  
Development Devices  
COP8TAB9  
COP8TAC9  
Free  
All packages. Obtain samples from: www.national.com  
<
*Cost: Free; VL= $100; L=$100-$300; M=$300-$1k; H=$1k-$3k; VH=$3k-$5k  
www.national.com  
48  
19.0 Development Support (Continued)  
19.2 COP8 TOOLS OVERVIEW  
COP8 Evaluation Software and Reference Designs -  
Software and Hardware for: Evaluation of COP8 Development Environments; Learning about COP8 Architecture and  
Features; Demonstrating Application Specific Capabilities.  
Product  
WCOP8 IDE and  
Software  
Description  
Source  
Software Evaluation downloads for Windows. Includes WCOP8 IDE evaluation  
version, Full COP8 Assembler/Linker, COP8-SIM Instruction Level Simulator or Unis  
Simulator, Byte Craft COP8C Compiler Demo, IAR Embedded Workbench  
(Assembler version), Manuals, Applications Software, and other COP8 technical  
information.  
www.national.com/cop8  
FREE Download  
Downloads  
COP8 Starter Kits and Hardware Target Solutions -  
Hardware Kits for: In-depth Evaluation and Testing of COP8 capabilities; Developing and Testing Code; Implementing  
Target Design.  
Product  
COP8TAC  
Description  
Source  
COP8–DB-TAC - A Code Development Tool for 2.5V COP8FLASH Families. A  
Windows IDE with Assembler and Simulator, combined with a simple realtime target  
environment. Quickly design and simulate your code, then download to the target  
COP8FLASH device for execution and simple debugging. Includes a library of  
software routines, and source code. No power supply.  
NSC Distributor,  
or Order from:  
Starter Kits  
www.national.com/cop8  
(Add a COP8-IMFLASH-LV Emulator for advanced emulation and debugging)  
COP8 Software Development Languages and Integrated Environments -  
Integrated Software for: Project Management; Code Development; Simulation and Debug.  
Description  
Product  
WCOP8 IDE  
from National on  
CD-ROM  
Source  
National’s COP8 Software Development package for Windows on CD. Fully licensed  
versions of our WCOP8 IDE and Emulator Debugger, with Assembler/ Linker/  
Simulators/ Library Manager/ Compiler Demos/ Flash ISP and NiceMon Debugger  
Utilities/ Example Code/ etc. Includes all COP8 datasheets and documentation.  
Included with most tools from National.  
NSC Distributor,  
or Order from:  
www.national.com/cop8  
Unis Processor  
Expert  
Processor Expert( from Unis Corporation - COP8 Code Generation and Simulation  
tool with Graphical and Traditional user interfaces. Automatically generates  
customized source code "Beans" (modules) containing working code for all on-chip  
features and peripherals, then integrates them into a fully functional application code  
design, with all documentation.  
Unis, or Order  
from:  
www.national.com/cop8  
Byte Craft  
ByteCraft COP8C- C Cross-Compiler and Code Development System. Includes  
BCLIDE (Integrated Development Environment) for Win32, editor, optimizing C  
Cross-Compiler, macro cross assembler, BC-Linker, and MetaLinktools support.  
(DOS/SUN versions available; Compiler is linkable under WCOP8 IDE)  
IAR EWCOP8 - ANSI C-Compiler and Embedded Workbench. A fully integrated  
Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, librarian, and C-Spy  
high-level simulator/debugger. (EWCOP8-M version includes COP8Flash Emulator  
support) (EWCOP8-BL version is limited to 4k code limit; no FP).  
ByteCraft  
COP8C Compiler  
Distributor,  
or Order from:  
www.national.com/cop8  
IAR Distributor,  
or Order from:  
IAR Embedded  
Workbench  
www.national.com/cop8  
COP8 Hardware Emulation/Debug Tools -  
Hardware Tools for: Real-time Emulation; Target Hardware Debug; Target Design Test.  
Description  
Product  
COP8Flash  
Source  
COP8 In-Circuit Emulator for Flash Families. Windows based development and  
real-time in-circuit emulation tool with 32k, trace 32k s/w breakpoints,  
source/symbolic debugger, and device programming. Includes COP8-NSDEV CD,  
Null Target, emulation cable with 2x7 connector, and power supply.  
A simple, single-step debug monitor with one breakpoint. MICROWIRE interface.  
NSC Distributor,  
or Order from:  
Emulators -  
COP8-IMFlash  
www.national.com/cop8  
NiceMon Debug  
Monitor Utility  
Download from:  
www.national.com/cop8  
49  
www.national.com  
19.0 Development Support (Continued)  
Development and Production Programming Tools -  
Programmers for: Design Development; Hardware Test; Pre-Production; Full Production.  
Description  
Product  
COP8 FLASH  
Emulators  
Source  
COP8 FLASH Emulators include in-circuit device programming capability during  
development.  
NSC Distributor, or  
Order from:  
www.national.com/cop8  
Download from:  
NiceMon  
National’s software Utilities "KANDAFLASH" and "NiceMon" provide  
development In-System-Programming for our FLASH Starter Kit, our Prototype  
Development Board, or any other target board with appropriate connectors.  
The COP8-ISP programmer from KANDA is available for engineering, and small  
volume production use. USB interface.  
Debugger,  
www.national.com/cop8  
KANDAFLASH  
KANDA COP8  
USB ISP  
www.kanda.com  
SofTec Micro  
inDart COP8  
Third-Party  
Programmers  
Factory  
The inDart COP8 programmer from SofTec is available for engineering and  
small volume production use. PC serial interface only.  
www.softecmicro.com  
Third-party programmers and automatic handling equipment are approved for  
non-ISP engineering and production use.  
Factory programming available for high-volume requirements and LLP  
production.  
National  
Programming  
Representative  
19.3 WHERE TO GET TOOLS  
Tools can be ordered directly from National, National’s e-store (Worldwide delivery: http://www.national.com/store/) , a National  
Distributor, or from the tool vendor. Go to the vendor’s web site for current listings of distributors.  
Vendor  
Home Office  
421 King Street North  
Waterloo, Ontario  
Canada N2J 4E4  
Tel: 1-(519) 888-6911  
Fax: (519) 746-6751  
PO Box 23051  
Electronic Sites  
www.bytecraft.com  
Other Main Offices  
Byte Craft Limited  
Distributors Worldwide  
@
info bytecraft.com  
IAR Systems AB  
www.iar.se  
USA:: San Francisco  
Tel: +1-415-765-5500  
Fax: +1-415-765-5503  
UK: London  
@
info iar.se  
S-750 23 Uppsala  
Sweden  
@
info iar.com  
@
info iarsys.co.uk  
Tel: +46 18 16 78 00  
Fax +46 18 16 78 38  
@
info iar.de  
Tel: +44 171 924 33 34  
Fax: +44 171 924 53 41  
Germany: Munich  
Tel: +49 89 470 6022  
Fax: +49 89 470 956  
USA:  
Embedded Results  
Ltd.  
P.O. Box 200,  
www.kanda.com  
@
Aberystwyth,  
sales kanda.co  
Tel/Fax: 800-510-3609  
@
SY23 2WD, UK  
info ucpros.com  
Tel/Fax: +44 (0)8707 446 807  
Kaergaardsvej 42 DK-8355  
Solbjerg Denmark  
Fax: +45-8692-8500  
2900 Semiconductor Dr.  
Santa Clara, CA 95051  
USA  
www.ucpros.com  
@
K and K  
www.kkd.dk kkd kkd.dk  
Development ApS  
National  
www.national.com/cop8  
Europe:  
@
Semiconductor  
support nsc.com  
Tel: 49(0) 180 530 8585  
Fax: 49(0) 180 530 8586  
Hong Kong:  
@
europe.support nsc.com  
Tel: 1-800-272-9959  
Fax: 1-800-737-7018  
Distributors Worldwide  
www.national.com  
50  
19.0 Development Support (Continued)  
Vendor  
SofTec Microsystems Via Roma, 1  
33082 Azzano Decimo (PN)  
Home Office  
Electronic Sites  
Other Main Offices  
Germany:  
@
info softecmicro.com  
www.softecmicro.com  
@
support softecmicro.com  
Tel.:+49 (0) 8761 63705  
France:  
Italy  
Tel: +39 0434 640113  
Fax: +39 0434 631598  
Tel: +33 (0) 562 072 954  
UK:  
Tel: +44 (0) 1970 621033  
The following companies have approved COP8 programmers in a variety of configurations. Contact your vendor’s local office  
or distributor and request a COP8FLASH update. You can link to their web sites and get the latest listing of approved  
programmers at: www.national.com/cop8.  
Advantech; BP Microsystems; Data I/O; Dataman; Hi-Lo Systems; KANDA, Lloyd Research; MQP; Needhams; Phyton; SofTec  
Microsystems; System General; and Tribal Microsystems.  
51  
www.national.com  
20.0 Revision History  
Date  
Section  
Summary of Changes  
August, 2004  
Final Datasheet Release.  
www.national.com  
52  
21.0 Physical Dimensions inches (millimeters) unless otherwise noted  
LLP Package  
Order Number COP8TAB5HLQ8 or COP8TAC5HLQ8  
NS Package Number LQA44A  
SOIC Wide Package  
Order Number COP8TAB5EMW8 or COP8TAC5EMW8  
NS Package Number M28B  
53  
www.national.com  
21.0 Physical Dimensions inches (millimeters) unless otherwise noted (Continued)  
SOIC Wide Package  
Order Number COP8TAB5CMW8 or COP8TAC5CMW8  
NS Package Number M20B  
LIFE SUPPORT POLICY  
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT  
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL  
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:  
1. Life support devices or systems are devices or  
systems which, (a) are intended for surgical implant  
into the body, or (b) support or sustain life, and  
whose failure to perform when properly used in  
accordance with instructions for use provided in the  
labeling, can be reasonably expected to result in a  
significant injury to the user.  
2. A critical component is any component of a life  
support device or system whose failure to perform  
can be reasonably expected to cause the failure of  
the life support device or system, or to affect its  
safety or effectiveness.  
BANNED SUBSTANCE COMPLIANCE  
National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products  
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification  
(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.  
National Semiconductor  
Americas Customer  
Support Center  
National Semiconductor  
Europe Customer Support Center  
Fax: +49 (0) 180-530 85 86  
National Semiconductor  
Asia Pacific Customer  
Support Center  
National Semiconductor  
Japan Customer Support Center  
Fax: 81-3-5639-7507  
Email: new.feedback@nsc.com  
Tel: 1-800-272-9959  
Email: europe.support@nsc.com  
Deutsch Tel: +49 (0) 69 9508 6208  
English Tel: +44 (0) 870 24 0 2171  
Français Tel: +33 (0) 1 41 91 8790  
Email: ap.support@nsc.com  
Email: jpn.feedback@nsc.com  
Tel: 81-3-5639-7560  
www.national.com  
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.  

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