COP888CG-XXX/V [NSC]

8-Bit Microcontroller with UART and Three Multi-Function Timers; 8位微控制器的UART及三幅多功能定时器
COP888CG-XXX/V
型号: COP888CG-XXX/V
厂家: National Semiconductor    National Semiconductor
描述:

8-Bit Microcontroller with UART and Three Multi-Function Timers
8位微控制器的UART及三幅多功能定时器

微控制器
文件: 总42页 (文件大小:474K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
August 1996  
COP884CG/COP888CG 8-Bit Microcontroller  
with UART and Three Multi-Function Timers  
Y
Schmitt trigger inputs on Port G  
General Description  
The COP888 family of microcontrollers uses an 8-bit single  
Y
Packages:  
Ð 44 PLCC with 40 I/O pins  
chip core architecture fabricated with National Semiconduc-  
Ð 40 DIP with 36 I/O pins  
Ð 28 DIP with 24 I/O pins  
2
tor’s M CMOSTM process technology. The COP888CG is a  
member of this expandable 8-bit core processor family of  
Ð 28 SO with 24 I/O pins  
microcontrollers.  
(Continued)  
CPU/Instruction Set Feature  
Y
Key Features  
Y
1 ms instruction cycle time  
Full duplex UART  
Y
Fourteen multi-source vectored interrupts servicing  
Ð External interrupt with selectable edge  
Ð Idle timer T0  
Y
Three 16-bit timers, each with two 16-bit registers sup-  
porting:  
Ð Processor independent PWM mode  
Ð External event counter mode  
Ð Input capture mode  
Ð Three timers (each with 2 interrupts)  
Ð MICROWIRE/PLUS  
Ð Multi-Input WAke Up  
Ð Software trap  
Ð UART (2)  
Y
Y
Y
Quiet design (low radiated emissions)  
4 kbytes of on-chip ROM  
192 bytes of on-chip RAM  
Ð Default VIS (default interrupt)  
Versatile and easy to use instruction set  
8-bit Stack Pointer (SP)Ðstack in RAM  
Two 8-bit register indirect data memory pointers (B, X)  
Y
Y
Y
Additional Peripheral Features  
Y
Idle timer  
Y
Multi-Input Wake Up (MIWU) with optional interrupts (8)  
Y
Two analog comparators  
WATCHDOGTM and Clock Monitor logic  
Fully Static CMOS  
Y
Y
Y
Y
k
1 mA)  
Low current drain (typically  
Y
MICROWIRE/PLUSTM serial I/O  
Single supply operation: 2.5V to 6.0V  
b
a
Temperature range: 40 C to 85 C  
§
§
I/O Features  
Y
Memory mapped I/O  
Development Support  
Y
Y
Software selectable I/O options (TRI-STATE output,  
É
push-pull output, weak pull-up input, high impedance in-  
put)  
Emulation and OTP devices  
Y
Real time emulation and full program debug offered by  
MetaLink Development System  
Y
High current outputs  
Block Diagram  
TL/DD/9765–1  
FIGURE 1. Block Diagram  
TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.  
2
MICROWIRE/PLUSTM, M CMOSTM, COP8TM microcontrollers, MICROWIRETM and WATCHDOGTM are trademarks of National Semiconductor Corporation.  
iceMASTERTM is a trademark of MetaLink Corporation.  
C
1996 National Semiconductor Corporation  
TL/DD/9765  
RRD-B30M106/Printed in U. S. A.  
http://www.national.com  
General Description (Continued)  
They are fully static parts, fabricated using double-metal sili-  
con gate microCMOS technology. Features include an 8-bit  
memory mapped architecture, MICROWIRE/PLUS serial  
I/O, three 16-bit timer/counters supporting three modes  
(Processor Independent PWM generation, External Event  
counter, and Input Capture mode capabilities), full duplex  
UART, two comparators, and two power savings modes  
(HALT and IDLE), both with a multi-sourced wakeup/inter-  
rupt capability. This multi-sourced interrupt capability may  
also be used independent of the HALT or IDLE modes.  
Each I/O pin has software selectable configurations. The  
device operates over a voltage range of 2.5V to 6V. High  
throughput is achieved with an efficient, regular instruction  
set operating at a maximum of 1 ms per instruction rate.  
The device has reduced EMI emissions. Low radiated emis-  
sions are achieved by gradual turn-on output drivers and  
internal I  
filters on the chip logic and crystal oscillator.  
CC  
Connection Diagrams  
Plastic Chip Carrier  
Dual-In-Line Package  
TL/DD/9765–2  
Top View  
Order Number COP888CG-XXX/V  
See NS Plastic Chip Package Number V44A  
TL/DD/9765–4  
Top View  
Order Number COP888CG-XXX/N  
See NS Molded Package Number N40A  
Dual-In-Line Package  
TL/DD/9765–5  
Top View  
Order Number COP884CG-XXX/N or COP884CG-XXX/WM  
See NS Molded Package Number N28A OR M28B  
FIGURE 2a. Connection Diagrams  
http://www.national.com  
2
Connection Diagrams (Continued)  
Pinouts for 28-, 40- and 44-Pin Packages  
28-Pin  
Pack.  
40-Pin  
Pack.  
44-Pin  
Pack.  
Port  
L0  
Type  
I/O  
Alt. Fun  
MIWU  
Alt. Fun  
11  
12  
13  
14  
15  
16  
17  
18  
17  
18  
19  
20  
21  
22  
23  
24  
17  
18  
19  
20  
25  
26  
27  
28  
L1  
L2  
L3  
L4  
L5  
L6  
L7  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
CKX  
TDX  
RDX  
T2A  
T2B  
T3A  
T3B  
G0  
G1  
G2  
G3  
G4  
G5  
G6  
G7  
I/O  
INT  
25  
26  
27  
28  
1
35  
36  
37  
38  
3
39  
40  
41  
42  
3
WDOUT  
I/O  
T1B  
I/O  
T1A  
I/O  
SO  
I/O  
SK  
2
4
4
I
SI  
3
5
5
I/CKO  
HALT Restart  
4
6
6
D0  
D1  
D2  
D3  
O
O
O
O
19  
20  
21  
22  
25  
26  
27  
28  
29  
30  
31  
32  
I0  
I1  
I2  
I3  
I
I
I
I
7
8
9
9
b
a
COMP1IN  
COMP1IN  
10  
11  
12  
10  
11  
12  
9
COMP1OUT  
10  
b
a
I4  
I5  
I6  
I7  
I
I
I
I
COMP2IN  
COMP2IN  
13  
14  
15  
16  
13  
14  
15  
16  
COMP2OUT  
D4  
D5  
D6  
D7  
O
O
O
O
29  
30  
31  
32  
33  
34  
35  
36  
C0  
C1  
C2  
C3  
C4  
C5  
C6  
C7  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
39  
40  
1
43  
44  
1
2
2
21  
22  
23  
24  
V
6
23  
5
8
33  
7
8
37  
7
CC  
GND  
CKI  
RESET  
24  
34  
38  
3
http://www.national.com  
Absolute Maximum Ratings  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales  
Office/Distributors for availability and specifications.  
Total Current out of GND Pin (Sink)  
Storage Temperature Range  
110 mA  
b
a
65 C to 140 C  
§
§
Note: Absolute maximum ratings indicate limits beyond  
which damage to the device may occur. DC and AC electri-  
cal specifications are not ensured when operating the de-  
vice at absolute maximum ratings.  
Supply Voltage (V  
)
CC  
7V  
b
a
0.3V  
Voltage at Any Pin  
Total Current into V Pin (Source)  
0.3V to V  
CC  
100 mA  
CC  
s
s
a
b
DC Electrical Characteristics 40 C  
T
A
85 C unless otherwise specified  
§
§
Parameter  
Operating Voltage  
Conditions  
Min  
Typ  
Max  
Units  
2.5  
6
V
V
Power Supply Ripple (Note 1)  
Supply Current (Note 2)  
Peak-to-Peak  
0.1 V  
CC  
e
e
e
e
e
e
e
e
e
e
CKI  
CKI  
CKI  
CKI  
10 MHz  
4 MHz  
4 MHz  
1 MHz  
V
CC  
V
CC  
V
CC  
V
CC  
6V, t  
6V, t  
1 ms  
8.0  
4.5  
2.5  
1.4  
mA  
mA  
mA  
mA  
c
2.5 ms  
c
e
4.0V, t  
4.0V, t  
2.5 ms  
10 ms  
c
c
e
k
e
e
e
HALT Current (Note 3)  
V
V
6V, CKI  
0 MHz  
1
10  
6
mA  
mA  
CC  
k
0.5  
e
4.0V, CKI  
0 MHz  
CC  
IDLE Current  
e
e
e
e
e
e
e
e
CKI  
CKI  
CKI  
10 MHz  
4 MHz  
1 MHz  
V
CC  
V
CC  
V
CC  
6V, t  
6V, t  
1 ms  
3.5  
2.5  
0.7  
mA  
mA  
mA  
c
2.5 ms  
c
e
4.0V, t  
10 ms  
c
Input Levels  
RESET  
Logic High  
0.8 V  
0.7 V  
0.7 V  
V
V
CC  
CC  
CC  
Logic Low  
0.2 V  
0.2 V  
0.2 V  
CC  
CC  
CC  
CKI (External and Crystal Osc. Modes)  
Logic High  
V
V
Logic Low  
All Other Inputs  
Logic High  
V
V
Logic Low  
e
e
b
a
2
Hi-Z Input Leakage  
V
V
6V  
2
mA  
mA  
V
CC  
e
b
b
250  
0.35 V  
Input Pullup Current  
6V, V  
0V  
40  
CC  
IN  
G and L Port Input Hysteresis  
CC  
Output Current Levels  
D Outputs  
e
e
e
e
e
OH  
b
b
Source  
V
CC  
V
CC  
V
CC  
V
CC  
4V, V  
3.3V  
0.4  
0.2  
mA  
mA  
mA  
mA  
e
2.5V, V  
OH  
1.8V  
1V  
e
Sink  
4V, V  
OL  
10  
2.0  
e
2.5V, V  
OL  
0.4V  
All Others  
e
e
e
e
e
e
e
b
b
100  
b
33  
Source (Weak Pull-Up Mode)  
V
CC  
V
CC  
V
CC  
V
CC  
V
CC  
V
CC  
4V, V  
OH  
2.7V  
10  
2.5  
0.4  
0.2  
mA  
mA  
mA  
mA  
mA  
mA  
e
b
b
b
2.5V, V  
OH  
1.8V  
e
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
4V, V  
OH  
3.3V  
e
2.5V, V  
OH  
1.8V  
e
4V, V  
OL  
0.4V  
1.6  
0.7  
e
2.5V, V  
0.4V  
OL  
e
b
a
2
TRI-STATE Leakage  
V
CC  
6.0V  
2
mA  
Note 1: Rate of voltage change must be less then 0.5 V/ms.  
Note 2: Supply current is measured after running 2000 cycles with a crystal/resonator oscillator, inputs at rails and outputs open.  
Note 3: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations. Test conditions: All inputs tied to V , L, C, and G0G5 configured  
CC  
as outputs and set high. The D port set to zero. The clock monitor and the comparators are disabled.  
http://www.national.com  
4
s
s
a
b
DC Electrical Characteristics 40 C  
T
A
85 C unless otherwise specified (Continued)  
§
§
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
Allowable Sink/Source  
Current per Pin  
D Outputs (Sink)  
All others  
15  
3
mA  
mA  
e
25 C  
Maximum Input Current  
without Latchup  
T
A
§
g
100  
mA  
V
RAM Retention Voltage, V  
500 ns Rise  
and Fall Time (Min)  
r
2
Input Capacitance  
7
pF  
pF  
Load Capacitance on D2  
1000  
s
s
a
b
AC Electrical Characteristics 40 C  
T
A
85 C unless otherwise specified  
§
§
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
Instruction Cycle Time (t )  
c
s
s
6V  
Crystal, Resonator,  
R/C Oscillator  
4V  
V
1
DC  
DC  
DC  
DC  
ms  
ms  
ms  
ms  
CC  
s
k
2.5V  
V
4V  
2.5  
3
CC  
s
s
4V  
V
CC  
6V  
s
k
4V  
2.5V  
V
7.5  
CC  
Inputs  
s
s
6V  
t
4V  
V
200  
500  
60  
ns  
ns  
ns  
ns  
SETUP  
CC  
s
k
2.5V  
V
4V  
CC  
s
s
t
4V  
V
CC  
6V  
HOLD  
s
k
4V  
2.5V  
V
150  
CC  
e
e
100 pF  
Output Propagation Delay (Note 4)  
, t  
R
L
2.2k, C  
L
t
PD1 PD0  
s
s
6V  
SO, SK  
4V  
V
0.7  
1.75  
1
ms  
ms  
ms  
ms  
CC  
s
k
2.5V  
V
4V  
CC  
s
s
All Others  
4V  
V
CC  
6V  
s
k
4V  
2.5V  
V
2.5  
CC  
MICROWIRETM Setup Time (t  
)
20  
56  
ns  
ns  
ns  
UWS  
MICROWIRE Hold Time (t  
)
UWH  
MICROWIRE Output Propagation Delay (t  
)
220  
UPD  
Input Pulse Width  
Interrupt Input High Time  
Interrupt Input Low Time  
Timer Input High Time  
Timer Input Low Time  
1
1
1
1
t
c
t
c
t
c
t
c
Reset Pulse Width  
1
ms  
Note 4: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs.  
5
http://www.national.com  
e
e
25 C  
Comparators AC and DC Characteristics V  
5V, T  
§
CC  
A
Parameter  
Input Offset Voltage  
Conditions  
Min  
Typ  
Max  
Units  
mV  
V
s
s
b
V
CC  
g
g
25  
0.4V  
V
IN  
1.5V  
10  
b
1.5  
Input Common Mode Voltage Range  
Low Level Output Current  
0.4  
1.6  
1.6  
V
CC  
e
e
V
V
0.4V  
4.6V  
mA  
mA  
OL  
High Level Output Current  
OH  
DC Supply Current Per Comparator  
(When Enabled)  
250  
mA  
ms  
Response Time  
TBD mV Step, TBD mV  
Overdrive, 100 pF Load  
1
TL/DD/9765–7  
FIGURE 2. MICROWIRE/PLUS Timing  
Pin Descriptions  
and GND are the power supply pins.  
V
CC  
TL/DD/9765–8  
CKI is the clock input. This can come from an R/C generat-  
ed oscillator, or a crystal oscillator (in conjunction with  
CKO). See Oscillator Description section.  
FIGURE 3. I/O Port Configurations  
PORT L is an 8-bit I/O port. All L-pins have Schmitt triggers  
on the inputs.  
RESET is the master reset input. See Reset Description  
section.  
The Port L supports Multi-Input Wake Up on all eight pins.  
L1 is used for the UART external clock. L2 and L3 are used  
for the UART transmit and receive. L4 and L5 are used for  
the timer input functions T2A and T2B. L6 and L7 are used  
for the timer input functions T3A and T3B.  
The device contains three bidirectional 8-bit I/O ports (C, G  
and L), where each individual bit may be independently con-  
figured as an input (Schmitt trigger inputs on ports L and G),  
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 two associated 8-bit memory  
mapped registers, the CONFIGURATION register and the  
output DATA register. A memory mapped address is also  
reserved for the input pins of each I/O port. (See the memo-  
ry map for the various addresses associated with the I/O  
ports.) Figure 3 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:  
The Port L has the following alternate features:  
L0  
L1  
L2  
L3  
L4  
L5  
L6  
L7  
MIWU  
MIWU or CKX  
MIWU or TDX  
MIWU or RDX  
MIWU or T2A  
MIWU or T2B  
MIWU or T3A  
MIWU or T3B  
Port G is an 8-bit port with 5 I/O pins (G0, G2G5), an input  
pin (G6), and two dedicated output pins (G1 and G7). Pins  
G0 and G2G6 all have Schmitt Triggers on their inputs. Pin  
G1 serves as the dedicated WDOUT WATCHDOG output,  
while pin G7 is either input or output depending on the oscil-  
lator mask option selected. With the crystal oscillator option  
selected, G7 serves as the dedicated output pin for the CKO  
clock output. With the single-pin R/C oscillator mask option  
selected, G7 serves as a general purpose input pin but is  
also used to bring the device out of HALT mode with a low  
to high transition on G7. There are two registers associated  
with the G Port, a data register and a configuration register.  
Therefore, each of the 5 I/O bits (G0, G2G5) can be indi-  
vidually configured under software control.  
CONFIGURATION  
Register  
DATA  
Port Set-Up  
Hi-Z Input  
Register  
0
0
(TRI-STATE Output)  
Input with Weak Pull-Up  
Push-Pull Zero Output  
Push-Pull One Output  
0
1
1
1
0
1
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6
Pin Descriptions (Continued)  
Functional Description  
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 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.  
The architecture of the device is modified Harvard architec-  
ture. With the Harvard architecture, the control store pro-  
gram memory (ROM) is separated from the data store mem-  
ory (RAM). Both ROM and RAM have their own separate  
addressing space with separate address buses. The archi-  
tecture, though based on Harvard architecture, permits  
transfer of data from ROM to RAM.  
Note that the chip will be placed in the HALT mode by writ-  
ing a ‘‘1’’ to bit 7 of the Port G Data Register. Similarly the  
chip will be placed in the IDLE mode by writing a ‘‘1’’ to bit 6  
of the Port G Data Register.  
CPU REGISTERS  
The CPU can do an 8-bit addition, subtraction, logical or  
shift operation in one instruction (t ) cycle time.  
c
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.  
There are six 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)  
Config Reg.  
CLKDLY  
Data Reg.  
HALT  
B is an 8-bit RAM address pointer, which can be optionally  
post auto incremented or decremented.  
G7  
G6  
X is an 8-bit alternate RAM address pointer, which can be  
optionally post auto incremented or decremented.  
Alternate SK  
IDLE  
Port G has the following alternate features:  
G0 INTR (External Interrupt Input)  
G2 T1B (Timer T1 Capture Input)  
G3 T1A (Timer T1 I/O)  
SP is the 8-bit stack pointer, which points to the subroutine/  
interrupt stack (in RAM). The SP is initialized to RAM ad-  
dress 06F with reset.  
S is the 8-bit Data Segment Address Register used to ex-  
tend the lower half of the address range (00 to 7F) into 256  
data segments of 128 bytes each.  
G4 SO (MICROWIRETM Serial Data Output)  
G5 SK (MICROWIRE Serial Clock)  
All the CPU registers are memory mapped with the excep-  
tion of the Accumulator (A) and the Program Counter (PC).  
G6 SI (MICROWIRE Serial Data Input)  
Port G has the following dedicated functions:  
PROGRAM MEMORY  
G1 WDOUT WATCHDOG and/or Clock Monitor dedicat-  
ed output  
The program memory consists of 4096 bytes of ROM.  
These bytes may hold program instructions or constant 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 devices vector to program  
memory location 0FF Hex.  
G7 CKO Oscillator dedicated output or general purpose  
input  
Port C is an 8-bit I/O port. The 40-pin device does not have  
a full complement of Port C pins. The unavailable pins are  
not terminated. A read operation for these unterminated  
pins will return unpredicatable values.  
DATA MEMORY  
PORT I is an eight-bit Hi-Z input port. The 28-pin device  
does not have a full complement of Port I pins. The unavail-  
able pins are not terminated i.e., they are floating. A read  
operation for these unterminated pins will return unpredict-  
able values. The user must ensure that the software takes  
this into account by either masking or restricting the access-  
es to bit operations. The unterminated Port I pins will draw  
power only when addressed.  
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, and the various registers, and counters asso-  
ciated with the timers (with the exception of the IDLE timer).  
Data memory is addressed directly by the instruction or indi-  
rectly by the B, X, SP pointers and S register.  
The device has 192 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 decre-  
mented and tested with the DRSZ (decrement register and  
skip if zero) instruction. The memory pointer registers X, SP,  
B and S are memory mapped into this space at address  
locations 0FC to 0FF Hex respectively, with the other regis-  
ters being available for general usage.  
Port I1I3 are used for Comparator 1. Port I4I6 are used  
for Comparator 2.  
The Port I has the following alternate features.  
b
COMP1 IN (Comparator 1 Negative Input)  
I1  
I2  
I3  
I4  
I5  
I6  
a
COMP1 IN (Comparator 1 Positive Input)  
COMP1OUT (Comparator 1 Output)  
b
COMP2 IN (Comparator 2 Negative Input)  
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.  
Note: RAM contents are undefined upon power-up.  
a
COMP2 IN (Comparator 2 Positive Input)  
COMP2OUT (Comparator 2 Output)  
Port D is an 8-bit output port that is preset high when  
RESET goes low. The user can tie two or more D port out-  
puts together in order to get a higher drive.  
7
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Data Memory Segment RAM Extension  
Data memory address 0FF is used as a memory mapped  
location for the Data Segment Address Register (S).  
(beyond the initial 128 bytes) are memory mapped at ad-  
dress locations 0100 to 013F hex.  
The data store memory is either addressed directly by a  
single byte address within the instruction, or indirectly rela-  
tive to the reference of the B, X, or SP pointers (each con-  
tains a single-byte address). This single-byte address allows  
an addressing range of 256 locations from 00 to FF hex.  
The upper bit of this single-byte address divides the data  
store memory into two separate sections as outlined previ-  
ously. With the exception of the RAM register memory from  
address locations 00F0 to 00FF, all RAM memory is memo-  
ry mapped with the upper bit of the single-byte address be-  
ing equal to zero. This allows the upper bit of the single-byte  
address to determine whether or not the base address  
range (from 0000 to 00FF) is extended. If this upper bit  
equals one (representing address range 0080 to 00FF),  
then address extension does not take place. Alternatively, if  
this upper bit equals zero, then the data segment extension  
register S is used to extend the base address range (from  
0000 to 007F) from XX00 to XX7F, where XX represents the  
8 bits from the S register. Thus the 128-byte data segment  
extensions are located from addresses 0100 to 017F for  
data segment 1, 0200 to 027F for data segment 2, etc., up  
to FF00 to FF7F for data segment 255. The base address  
range from 0000 to 007F represents data segment 0.  
TL/DD/9765–9  
*Reads as all ones.  
FIGURE 4. RAM Organization  
Figure 4 illustrates how the S register data memory exten-  
sion is used in extending the lower half of the base address  
range (00 to 7F hex) into 256 data segments of 128 bytes  
each, with a total addressing range of 32 kbytes from XX00  
to XX7F. This organization allows a total of 256 data seg-  
ments of 128 bytes each with an additional upper base seg-  
ment of 128 bytes. Furthermore, all addressing modes are  
available for all data segments. The S register must be  
changed under program control to move from one data seg-  
ment (128 bytes) to another. However, the upper base seg-  
ment (containing the 16 memory registers, I/O registers,  
control registers, etc.) is always available regardless of the  
contents of the S register, since the upper base segment  
(address range 0080 to 00FF) is independent of data seg-  
ment extension.  
Reset  
The RESET input when pulled low initializes the microcon-  
troller. Initialization will occur whenever the RESET input is  
pulled low. Upon initialization, the data and configuration  
registers for ports L, G and C are cleared, resulting in these  
Ports being initialized to the TRI-STATE mode. Pin G1 of the  
G Port is an exception (as noted below) since pin G1 is  
dedicated as the WATCHDOG and/or Clock Monitor error  
output pin. Port D is set high. The PC, PSW, ICNTRL,  
CNTRL, T2CNTRL and T3CNTRL control registers are  
cleared. The UART registers PSR, ENU (except that TBMT  
bit is set), ENUR and ENUI are cleared. The Comparator  
Select Register is cleared. The S register is initialized to  
zero. The Multi-Input Wakeup registers WKEN, WKEDG and  
WKPND are cleared. The stack pointer, SP, is initialized to  
6F Hex.  
The instructions that utilize the stack pointer (SP) always  
reference the stack as part of the base segment (Segment  
0), regardless of the contents of the S register. The S regis-  
ter is not changed by these instructions. Consequently, the  
stack (used with subroutine linkage and interrupts) is always  
located in the base segment. The stack pointer will be inti-  
tialized to point at data memory location 006F as a result of  
reset.  
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 Monitor  
bit set. The WATCHDOG and Clock Monitor circuits are in-  
hibited during reset. The WATCHDOG service window bits  
being initialized high default to the maximum WATCHDOG  
service window of 64k t clock cycles. The Clock Monitor bit  
C
The 128 bytes of RAM contained in the base segment are  
split between the lower and upper base segments. The first  
116 bytes of RAM are resident from address 0000 to 006F  
in the lower base segment, while the remaining 16 bytes of  
RAM represent the 16 data memory registers located at ad-  
dresses 00F0 to 00FF of the upper base segment. No RAM  
is located at the upper sixteen addresses (0070 to 007F) of  
the lower base segment.  
being initialized high will cause a Clock Monitor error follow-  
ing 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 t 32 t clock cycles following  
C
C
the clock frequency reaching the minimum specified value,  
at which time the G1 output will enter the TRI-STATE mode.  
The external RC network shown in Figure 5 should be used  
to ensure that the RESET pin is held low until the power  
supply to the chip stabilizes.  
Additional RAM beyond these initial 128 bytes, however, will  
always be memory mapped in groups of 128 bytes (or less)  
at the data segment address extensions (XX00 to XX7F) of  
the lower base segment. The additional 64 bytes of RAM  
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8
e
TABLE A. Crystal Oscillator Configuration, T  
25 C  
§
A
Reset (Continued)  
R1  
R2  
C1  
C2  
CKI Freq  
(MHz)  
Conditions  
(kX) (MX) (pF)  
(pF)  
e
5V  
0
0
0
1
1
1
30  
30  
3036  
3036  
10  
4
V
CC  
e
V
5.0V  
CC  
e
200 100150  
0.455  
V
5V  
CC  
e
TABLE B. RC Oscillator Configuration, T  
25 C  
§
A
TL/DD/976510  
R
C
CKI Freq  
(MHz)  
Instr. Cycle  
Conditions  
l
c
Power Supply Rise Time  
RC  
5
(kX)  
(pF)  
(ms)  
FIGURE 5. Recommended Reset Circuit  
e
e
e
3.3  
5.6  
6.8  
82  
2.2 to 2.7  
1.1 to 1.3  
0.9 to 1.1  
3.7 to 4.6  
7.4 to 9.0  
8.8 to 10.8  
V
CC  
V
CC  
V
CC  
5V  
5V  
5V  
100  
100  
Oscillator Circuits  
The chip can be driven by a clock input on the CKI input pin  
which can be between DC and 10 MHz. The CKO output  
clock is on pin G7 (crystal configuration). The CKI input fre-  
quency is divided down by 10 to produce the instruction  
s
s
200k  
Note: 3k  
R
s
s
200 pF  
50 pF  
C
cycle clock (1/t ).  
c
Control Registers  
CNTRL Register (Address X 00EE)  
Figure 6 shows the Crystal and R/C diagrams.  
Ê
The Timer1 (T1) and MICROWIRE/PLUS control register  
contains the following bits:  
CRYSTAL OSCILLATOR  
CKI and CKO can be connected to make a closed loop  
crystal (or resonator) controlled oscillator.  
SL1 & SL0 Select the MICROWIRE/PLUS clock divide  
e
8)  
e
e
by (00  
2, 01  
4, 1x  
Table A shows the component values required for various  
standard crystal values.  
IEDG  
MSEL  
T1C0  
External interrupt edge polarity select  
e
Falling edge)  
e
(0  
Rising edge, 1  
R/C OSCILLATOR  
Selects G5 and G4 as MICROWIRE/PLUS  
signals SK and SO respectively  
By selecting CKI as a single pin oscillator input, a single pin  
R/C oscillator circuit can be connected to it. CKO is avail-  
able as a general purpose input, and/or HALT restart input.  
Timer T1 Start/Stop control in timer  
modes 1 and 2  
Table B shows the variation in the oscillator frequencies as  
functions of the component (R and C) values.  
Timer T1 Underflow Interrupt Pending Flag in  
timer mode 3  
T1C1  
T1C2  
T1C3  
Timer T1 mode control bit  
Timer T1 mode control bit  
Timer T1 mode control bit  
T1C3 T1C2 T1C1 T1C0 MSEL IEDG SL1  
Bit 7  
SL0  
Bit 0  
TL/DD/976512  
TL/DD/976511  
FIGURE 6. Crystal and R/C Oscillator Diagrams  
9
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Control Registers (Continued)  
PSW Register (Address X 00EF)  
T2C1  
T2C2  
T2C3  
Timer T2 mode control bit  
Timer T2 mode control bit  
Timer T2 mode control bit  
Ê
The PSW register contains the following select bits:  
GIE  
Global interrupt enable (enables interrupts)  
Enable external interrupt  
EXEN  
BUSY  
T2C3 T2C2 T2C1 T2C0 T2PNDA T2ENA T2PNDB T2ENB  
MICROWIRE/PLUS busy shifting flag  
EXPND External interrupt pending  
Bit 7  
Bit 0  
T1ENA Timer T1 Interrupt Enable for Timer Underflow  
or T1A Input capture edge  
T3CNTRL Register (Address X 00B6)  
Ê
The T3CNTRL register contains the following bits:  
T1PNDA Timer T1 Interrupt Pending Flag (Autoreload RA  
in mode 1, T1 Underflow in Mode 2, T1A cap-  
ture edge in mode 3)  
T3ENB Timer T3 Interrupt Enable for T3B  
T3PNDB Timer T3 Interrupt Pending Flag for T3B pin  
(T3B capture edge)  
C
Carry Flag  
T3ENA Timer T3 Interrupt Enable for Timer Underflow  
or T3A pin  
HC  
Half Carry Flag  
T3PNDA Timer T3 Interrupt Pending Flag (Autoload RA  
in mode 1, T3 Underflow in mode 2, T3a cap-  
ture edge in mode 3)  
HC  
Bit 7  
C
T1PNDA T1ENA EXPND BUSY EXEN GIE  
Bit 0  
The Half-Carry bit 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 car-  
ry flags. In addition to the SC and RC instructions, ADC,  
SUBC, RRC and RLC instructions affect the carry and Half  
Carry flags.  
T3C0  
Timer T3 Start/Stop control in timer modes 1  
and 2  
Timer T3 Underflow Interrupt Pending Flag in  
timer mode 3  
T3C1  
T3C2  
T3C3  
Timer T3 mode control bit  
Timer T3 mode control bit  
Timer T3 mode control bit  
ICNTRL Register (Address X 00E8)  
Ê
The ICNTRL register contains the following bits:  
T1ENB Timer T1 Interrupt Enable for T1B Input capture  
edge  
T3C3 T3C2 T3C1 T3C0 T3PNDA T3ENA T3PNDB T3ENB  
Bit 7  
Bit 0  
T1PNDB Timer T1 Interrupt Pending Flag for T1B cap-  
ture edge  
Timers  
mWEN Enable MICROWIRE/PLUS interrupt  
mWPND MICROWIRE/PLUS interrupt pending  
The device contains a very versatile set of timers (T0, T1,  
T2, T3). All timers and associated autoreload/capture regis-  
ters power up containing random data.  
T0EN  
T0PND Timer T0 Interrupt pending  
LPEN L Port Interrupt Enable (Multi-Input Wakeup/In-  
Timer T0 Interrupt Enable (Bit 12 toggle)  
TIMER T0 (IDLE TIMER)  
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 Timer T0 runs continuously at the fixed  
terrupt)  
Bit 7 could be used as a flag  
Unused LPEN T0PND T0EN mWPND mWEN T1PNDB T1ENB  
rate of the instruction cycle clock, t . The user cannot read  
c
or write to the IDLE Timer T0, which is a count down timer.  
Bit 7  
Bit 0  
The Timer T0 supports the following functions:  
T2CNTRL Register (Address X 00C6)  
Ê
The T2CNTRL register contains the following bits:  
Exit out of the Idle Mode (See Idle Mode description)  
WATCHDOG logic (See WATCHDOG description)  
Start up delay out of the HALT mode  
T2ENB Timer T2 Interrupt Enable for T2B Input capture  
edge  
The IDLE Timer T0 can generate an interrupt when the thir-  
teenth bit toggles. This toggle is latched into the T0PND  
pending flag, and will occur every 4 ms at the maximum  
T2PNDB Timer T2 Interrupt Pending Flag for T2B cap-  
ture edge  
e
clock frequency (t  
1 ms). A control flag T0EN allows the  
c
T2ENA Timer T2 Interrupt Enable for Timer Underflow  
or T2A Input capture edge  
interrupt from the thirteenth bit of Timer T0 to be enabled or  
disabled. Setting T0EN will enable the interrupt, while reset-  
ting it will disable the interrupt.  
T2PNDA Timer T2 Interrupt Pending Flag (Autoreload RA  
in mode 1, T2 Underflow in mode 2, T2A cap-  
ture edge in mode 3)  
T2C0  
Timer T2 Start/Stop control in timer modes 1  
and 2 Timer T2 Underflow Interrupt Pending  
Flag in timer mode 3  
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10  
Timers (Continued)  
TIMER T1, TIMER T2 AND TIMER T3  
The device has  
a set of three powerful timer/counter  
blocks, T1, T2 and T3. The associated features and func-  
tioning of a timer block are described by referring to the  
timer block Tx. Since the three timer blocks, T1, T2 and T3  
are identical, all comments are equally applicable to any of  
the three timer blocks.  
Each timer block consists of a 16-bit timer, Tx, and two  
supporting 16-bit autoreload/capture registers, RxA and  
RxB. Each timer block has two pins associated with it, TxA  
and TxB. The pin TxA supports I/O required by the timer  
block, while the pin TxB is an input to the timer block. The  
powerful and flexible timer block allows the device to easily  
perform all timer functions with minimal software overhead.  
The timer block has three operating modes: Processor Inde-  
pendent PWM mode, External Event Counter mode, and  
Input Capture mode.  
TL/DD/976514  
FIGURE 7. Timer in PWM Mode  
Mode 2. External Event Counter Mode  
The control bits TxC3, TxC2, and TxC1 allow selection of  
the different modes of operation.  
This mode is quite similar to the processor independent  
PWM mode described above. The main difference is that  
the timer, Tx, is clocked by the input signal from the TxA pin.  
The Tx timer control bits, TxC3, TxC2 and TxC1 allow the  
timer to be clocked either on a positive or negative edge  
from the TxA pin. Underflows from the timer are latched into  
the TxPNDA pending flag. Setting the TxENA control flag  
will cause an interrupt when the timer underflows.  
Mode 1. Processor Independent PWM Mode  
As the name suggests, this mode allows the device to gen-  
erate a PWM signal with very minimal user intervention. The  
user only has to define the parameters of the PWM signal  
(ON time and OFF time). Once begun, the timer block will  
continuously generate the PWM signal completely indepen-  
dent of the microcontroller. The user software services the  
timer block only when the PWM parameters require updat-  
ing.  
In this mode the input pin TxB can be used as an indepen-  
dent positive edge sensitive interrupt input if the TxENB  
control flag is set. The occurrence of a positive edge on the  
TxB input pin is latched into the TxPNDB flag.  
In this mode the timer Tx counts down at a fixed rate of t .  
c
Upon every underflow the timer is alternately reloaded with  
the contents of supporting registers, RxA and RxB. The very  
first underflow of the timer causes the timer to reload from  
the register RxA. Subsequent underflows cause the timer to  
be reloaded from the registers alternately beginning with the  
register RxB.  
Figure 8 shows a block diagram of the timer in External  
Event Counter mode.  
Note: The PWM output is not available in this mode since the TxA pin is  
being used as the counter input clock.  
The Tx Timer control bits, TxC3, TxC2 and TxC1 set up the  
timer for PWM mode operation.  
Figure 7 shows a block diagram of the timer in PWM mode.  
The underflows can be programmed to toggle the TxA out-  
put pin. The underflows can also be programmed to gener-  
ate interrupts.  
Underflows from the timer are alternately latched into two  
pending flags, TxPNDA and TxPNDB. The user must reset  
these pending flags under software control. Two control en-  
able flags, TxENA and TxENB, allow the interrupts from the  
timer underflow to be enabled or disabled. Setting the timer  
enable flag TxENA will cause an interrupt when a timer un-  
derflow causes the RxA register to be reloaded into the tim-  
er. Setting the timer enable flag TxENB will cause an inter-  
rupt when a timer underflow causes the RxB register to be  
reloaded into the timer. Resetting the timer enable flags will  
disable the associated interrupts.  
TL/DD/976515  
FIGURE 8. Timer in External Event Counter Mode  
Mode 3. Input Capture Mode  
The device can precisely measure external frequencies or  
time external events by placing the timer block, Tx, in the  
input capture mode.  
Either or both of the timer underflow interrupts may be en-  
abled. 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 interrupt  
on both edges of the PWM output.  
In this mode, the timer Tx is constantly running at the fixed  
rate. The two registers, RxA and RxB, act as capture  
registers. Each register acts in conjunction with a pin. The  
register RxA acts in conjunction with the TxA pin and the  
register RxB acts in conjunction with the TxB pin.  
t
c
11  
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Timers (Continued)  
The timer value gets copied over into the register when a  
trigger event occurs on its corresponding pin. Control bits,  
TxC3, TxC2 and TxC1, allow the trigger events to be speci-  
fied either as a positive or a negative edge. The trigger con-  
dition 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 TxA and TxB pins will be respectively latched into the  
pending flags, TxPNDA and TxPNDB. The control flag  
TxENA allows the interrupt on TxA to be either enabled or  
disabled. Setting the TxENA flag enables interrupts to be  
generated when the selected trigger condition occurs on the  
TxA pin. Similarly, the flag TxENB controls the interrupts  
from the TxB pin.  
TL/DD/976516  
Underflows from the timer can also be programmed to gen-  
erate interrupts. Underflows are latched into the timer TxC0  
pending flag (the TxC0 control bit serves as the timer under-  
flow interrupt pending flag in the Input Capture mode). Con-  
sequently, the TxC0 control bit should be reset when enter-  
ing the Input Capture mode. The timer underflow interrupt is  
enabled with the TxENA control flag. When a TxA interrupt  
occurs in the Input Capture mode, the user must check both  
the TxPNDA and TxC0 pending flags in order to determine  
whether a TxA input capture or a timer underflow (or both)  
caused the interrupt.  
FIGURE 9. Timer in Input Capture Mode  
TIMER CONTROL FLAGS  
The timers T1, T2 and T3 have indentical control structures.  
The control bits and their functions are summarized below.  
TxC0  
Timer Start/Stop control in Modes 1 and 2  
(Processor Independent PWM and External  
e
e
Stop  
Event Counter), where 1  
Start, 0  
Timer Underflow Interrupt Pending Flag in  
Mode 3 (Input Capture)  
TxPNDA Timer Interrupt Pending Flag  
TxPNDB Timer Interrupt Pending Flag  
Figure 9 shows a block diagram of the timer in Input Capture  
mode.  
TxENA Timer Interrupt Enable Flag  
TxENB Timer Interrupt Enable Flag  
e
e
1
0
Timer Interrupt Enabled  
Timer Interrupt Disabled  
TxC3  
TxC2  
TxC1  
Timer mode control  
Timer mode control  
Timer mode control  
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12  
Timers (Continued)  
The timer mode control bits (TxC3, TxC2 and TxC1) are detailed below:  
Interrupt A  
Source  
Interrupt B  
Source  
Timer  
TxC3  
TxC2  
TxC1  
Timer Mode  
Counts On  
0
0
0
MODE 2 (External  
Event Counter)  
Timer  
Pos. TxB  
Edge  
TxA  
Underflow  
Pos. Edge  
0
1
1
0
0
0
0
1
1
1
0
0
MODE 2 (External  
Event Counter)  
Timer  
Pos. TxB  
Edge  
TxA  
Underflow  
Neg. Edge  
MODE 1 (PWM)  
TxA Toggle  
Autoreload  
RA  
Autoreload  
RB  
t
c
MODE 1 (PWM)  
No TxA Toggle  
Autoreload  
RA  
Autoreload  
RB  
t
t
c
MODE 3 (Capture)  
Captures:  
Pos. TxA  
Edge or  
Timer  
Pos. TxB  
Edge  
c
TxA Pos. Edge  
TxB Pos. Edge  
Underflow  
1
0
1
1
1
1
0
1
1
MODE 3 (Capture)  
Captures:  
Pos. TxA  
Edge or  
Timer  
Neg. TxB  
Edge  
t
c
t
c
t
c
TxA Pos. Edge  
TxB Neg. Edge  
Underflow  
MODE 3 (Capture)  
Captures:  
Neg. TxB  
Edge or  
Timer  
Pos. TxB  
Edge  
TxA Neg. Edge  
TxB Pos. Edge  
Underflow  
MODE 3 (Capture)  
Captures:  
Neg. TxA  
Edge or  
Timer  
Neg. TxB  
Edge  
TxA Neg. Edge  
TxB Neg. Edge  
Underflow  
Power Save Modes  
The device offers the user two power save modes of opera-  
tion: HALT and IDLE. In the HALT mode, all microcontroller  
activities are stopped. In the IDLE mode, the on-board oscil-  
lator circuitry the WATCHDOG logic, the Clock Monitor and  
timer T0 are active but all other microcontroller activities are  
stopped. In either mode, all on-board RAM, registers, I/O  
states, and timers (with the exception of T0) are unaltered.  
figuration (since CKO becomes a dedicated output), and so  
may be used with an RC clock configuration. The third  
method of exiting the HALT mode is by pulling the RESET  
pin low.  
Since a crystal or ceramic resonator may be selected as the  
oscillator, the Wakeup 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 ampli-  
tude and frequency stability. The IDLE timer is used to gen-  
erate a fixed delay to ensure that the oscillator has indeed  
stabilized before allowing instruction execution. In this case,  
upon detecting a valid Wakeup signal, only the oscillator  
circuitry is enabled. The IDLE timer is loaded with a value of  
HALT MODE  
The device can be placed in the HALT mode by writing a  
‘‘1’’ to the HALT flag (G7 data bit). All microcontroller activi-  
ties, including the clock and timers, are stopped. The  
WATCHDOG logic is disabled during the HALT mode. How-  
ever, 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  
256 and is clocked with the t instruction cycle clock. The t  
c
c
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 startup timeout  
from the IDLE timer enables the clock signals to be routed  
to the rest of the chip.  
device are minimal and the applied voltage (V ) may be  
CC  
e
decreased to V (V  
r
2.0V) without altering the state of the  
r
machine.  
If an RC clock option is being used, the fixed delay is intro-  
duced optionally. A control bit, CLKDLY, mapped as config-  
uration bit G7, controls whether the delay is to be intro-  
duced or not. The delay is included if CLKDLY is set, and  
excluded if CLKDLY is reset. The CLKDLY bit is cleared on  
reset.  
The device supports three different ways of exiting the  
HALT mode. The first method of exiting the HALT mode is  
with the Multi-Input Wakeup feature on the L port. The sec-  
ond method is with a low to high transition on the CKO (G7)  
pin. This method precludes the use of the crystal clock con-  
13  
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Power Save Modes (Continued)  
The device has two mask options associated with the HALT  
mode. The first mask option enables the HALT mode fea-  
ture, while the second mask option disables the HALT  
mode. With the HALT mode enable mask option, the device  
will enter and exit the HALT mode as described above. With  
the HALT disable mask option, the device cannot be placed  
in the HALT mode (writing a ‘‘1’’ to the HALT flag will have  
no effect).  
This toggle condition of the thirteenth 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 thirteenth 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.  
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 rou-  
tine and then return to the instruction following the ‘‘Enter  
Idle Mode’’ instruction.  
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.  
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 immediate-  
ly following the ‘‘Enter IDLE Mode’’ instruction.  
IDLE MODE  
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, the WATCH-  
DOG logic, the clock monitor and the IDLE Timer T0, are  
stopped.  
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 nor-  
mal operation with a reset, or with a Multi-Input Wakeup  
from the L Port. Alternately, the microcontroller resumes  
normal operation from the IDLE mode when the thirteenth  
bit (representing 4.096 ms at internal clock frequency of  
Multi-Input Wakeup  
The Multi-Input Wakeup feature is ued to return (wakeup)  
the device from either the HALT or IDLE modes. Alternately  
Multi-Input Wakeup/Interrupt feature may also be used to  
generate up to 8 edge selectable external interrupts.  
e
1 MHz, t  
1 ms) of the IDLE Timer toggles.  
c
Figure 10 shows the Multi-Input Wakeup logic.  
TL/DD/976517  
FIGURE 10. Multi-Input Wake Up Logic  
http://www.national.com  
14  
Multi-Input Wakeup (Continued)  
The Multi-Input Wakeup feature utilizes the L Port. The user  
selects which particular L port bit (or combination of L Port  
bits) will cause the device to exit the HALT or IDLE modes.  
The selection is done through the Reg: WKEN. The Reg:  
WKEN is an 8-bit read/write register, which contains a con-  
trol bit for every L port bit. Setting a particular WKEN bit  
enables a Wakeup from the associated L port pin.  
WKEN, WKPND and WKEDG are all read/write registers,  
and are cleared at reset.  
PORT L INTERRUPTS  
Port L provides the user with an additional eight fully select-  
able, edge sensitive interrupts which are all vectored into  
the same service subroutine.  
The interrupt from Port L shares logic with the wake up cir-  
cuitry. The register WKEN allows interrupts from Port L to  
be individually enabled or disabled. The register WKEDG  
specifies the trigger condition to be either a positive or a  
negative edge. Finally, the register WKPND latches in the  
pending trigger conditions.  
The user can select whether the trigger condition on the  
selected L Port pin is going to be either a positive edge (low  
to high transition) or a negative edge (high to low transition).  
This selection is made via the Reg: WKEDG, which is an 8-  
bit control register with a bit assigned to each L Port pin.  
Setting the control bit will select the trigger condition to be a  
negative edge on that particular L Port pin. Resetting the bit  
selects the trigger condition to be a positive edge. Changing  
an edge select entails several steps in order to avoid a  
pseudo Wakeup condition as a result of the edge change.  
First, the associated WKEN bit should be reset, followed by  
the edge select change in WKEDG. Next, the associated  
WKPND bit should be cleared, followed by the associated  
WKEN bit being re-enabled.  
The GIE (Global Interrupt Enable) bit enables the interrupt  
function.  
A control flag, LPEN, functions as a global interrupt enable  
for Port L interrupts. Setting the LPEN flag will enable inter-  
rupts and vice versa. A separate global pending flag is not  
needed since the register WKPND is adequate.  
Since Port L is 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 following the in-  
struction 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 normal oper-  
ation.  
An example may serve to clarify this procedure. Suppose  
we wish to change the edge select from positive (low going  
high) to negative (high going low) for L Port bit 5, where bit 5  
has previously been enabled for an input interrupt. The pro-  
gram would be as follows:  
RBIT 5, WKEN  
SBIT 5, WKEDG  
RBIT 5, WKPND  
SBIT 5, WKEN  
The Wakeup signal will not start the chip running immediate-  
ly since crystal oscillators or ceramic resonators have a fi-  
nite start up time. The IDLE Timer (T0) generates a fixed  
delay to ensure that the oscillator has indeed stabilized be-  
fore allowing the device to execute instructions. In this case,  
upon detecting a valid Wakeup signal, only the oscillator  
circuitry and the IDLE Timer T0 are enabled. The IDLE Tim-  
If the L port bits have been used as outputs and then  
changed to inputs with Multi-Input Wakeup/Interrupt, a safe-  
ty procedure should also be followed to avoid inherited  
pseudo wakeup conditions. After the selected L port bits  
have been changed from output to input but before the as-  
sociated WKEN bits are enabled, the associated edge se-  
lect bits in WKEDG should be set or reset for the desired  
edge selects, followed by the associated WKPND bits being  
cleared.  
er is loaded with a value of 256 and is clocked from the t  
c
instruction cycle clock. The t clock is derived by dividing  
c
down the oscillator clock by a factor of 10. A Schmitt trigger  
following the CKI on-chip inverter ensures that the IDLE tim-  
er 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  
startup timeout from the IDLE timer enables the clock sig-  
nals to be routed to the rest of the chip.  
This same procedure should be used following reset, since  
the L port inputs are left floating as a result of reset.  
The occurrence of the selected trigger condition for Multi-In-  
put Wakeup is latched into a pending register called  
WKPND. The respective bits of the WKPND register will be  
set on the occurrence of the selected trigger edge on the  
corresponding Port L pin. The user has the responsibility of  
clearing these pending flags. Since WKPND is a pending  
register for the occurrence of selected wakeup conditions,  
the device will not enter the HALT mode if any Wakeup bit is  
both enabled and pending. Consequently, the user has the  
responsibility of clearing the pending flags before attempt-  
ing to enter the HALT mode.  
If the RC clock option is used, the fixed delay is under soft-  
ware control. A control flag, CLKDLY, in the G7 configura-  
tion bit allows the clock start up delay to be optionally insert-  
ed. Setting CLKDLY flag high will cause clock start up delay  
to be inserted and resetting it will exclude the clock start up  
delay. The CLKDLY flag is cleared during reset, so the clock  
start up delay is not present following reset with the RC  
clock options.  
15  
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UART  
The COP888CG contains a full-duplex software program-  
mable UART. The UART (Figure 11) consists of a transmit  
shift register, a receiver shift register and seven address-  
able registers, as follows: a transmit buffer register (TBUF),  
Other functions of the ENUR register include saving the  
ninth bit received in the data frame, enabling or disabling the  
UART’s attention mode of operation and providing addition-  
al receiver/transmitter status information via RCVG and  
XMTG bits. The determination of an internal or external  
clock source is done by the ENUI register, as well as select-  
ing the number of stop bits and enabling or disabling trans-  
mit and receive interrupts. A control flag in this register can  
also select the UART mode of operation: asynchronous or  
synchronous.  
a
receiver buffer register (RBUF), a UART control and  
status register (ENU), a UART receive control and status  
register (ENUR), a UART interrupt and clock source register  
(ENUI), a prescaler select register (PSR) and baud (BAUD)  
register. The ENU register contains flags for transmit and  
receive functions; this register also determines the length of  
the data frame (7, 8 or 9 bits), the value of the ninth bit in  
transmission, and parity selection bits. The ENUR register  
flags framming, data overrun and parity errors while the  
UART is receiving.  
TL/DD/976518  
FIGURE 11. UART Block Diagram  
http://www.national.com  
16  
UART (Continued)  
UART CONTROL AND STATUS REGISTERS  
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PSEL1  
PSEL1  
1, PSEL0  
1, PSEL0  
0
1
Mark(1) (if Parity enabled)  
Space(0) (if Parity enabled)  
The operation of the UART is programmed through three  
registers: ENU, ENUR and ENUI. The function of the individ-  
ual bits in these registers is as follows:  
PEN: This bit enables/disables Parity (7- and 8-bit modes  
only).  
e
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PEN  
PEN  
0
1
Parity disabled.  
Parity enabled.  
ENU-UART Control and Status Register (Address at 0BA)  
PEN  
PSEL1 XBIT9/ CHL1 CHL0 ERR  
PSEL0  
RBFL TBMT  
0R 1R  
Bit 0  
ENURÐUART RECEIVE CONTROL AND  
STATUS REGISTER  
0RW 0RW 0RW 0RW 0RW 0R  
RCVG: This bit is set high whenever a framing error occurs  
and goes low when RDX goes high.  
Bit 7  
ENUR-UART Receive Control and Status Register  
(Address at 0BB)  
XMTG: This bit is set to indicate that the UART is transmit-  
ting. It gets reset at the end of the last frame (end of last  
Stop bit).  
DOE FE  
PE  
SPARE RBIT9 ATTN XMTG RCVG  
ATTN: ATTENTION Mode is enabled while this bit is set.  
This bit is cleared automatically on receiving a character  
with data bit nine set.  
0RD  
0RD  
0RD  
0RW* 0R  
0RW 0R  
0R  
Bit7  
Bit0  
RBIT9: Contains the ninth data bit received when the UART  
is operating with nine data bits per frame.  
ENUI-UART Interrupt and Clock Source Register  
(Address at 0BC)  
SPARE: Reserved for future use.  
STP2 STP78 ETDX SSEL XRCLK XTCLK ERI  
ETI  
PE: Flags a Parity Error.  
0RW 0RW 0RW 0RW 0RW 0RW 0RW 0RW  
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PE  
PE  
0
1
Indicates no Parity Error has been detected since  
the last time the ENUR register was read.  
Indicates the occurrence of a Parity Error.  
Bit7  
Bit0  
*Bit is not used.  
0
1
R
Bit is cleared on reset.  
FE: Flags a Framing Error.  
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Bit is set to one on reset.  
FE  
0
Indicates no Framing Error has been detected  
since the last time the ENUR register was read.  
Indicates the occurrence of a Framing Error.  
Bit is read-only; it cannot be written by software.  
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FE  
1
RW Bit is read/write.  
D
Bit is cleared on read; when read by software as a one, it is cleared  
automatically. Writing to the bit does not affect its state.  
DOE: Flags a Data Overrun Error.  
e
DOE  
0
Indicates no Data Overrun Error has been de-  
tected since the last time the ENUR register  
was read.  
DESCRIPTION OF UART REGISTER BITS  
ENUÐUART CONTROL AND STATUS REGISTER  
e
DOE  
1
Indicates the occurrence of a Data Overrun Er-  
ror.  
TBMT: This bit is set when the UART transfers a byte of  
data from the TBUF register into the TSFT register for trans-  
mission. It is automatically reset when software writes into  
the TBUF register.  
ENUIÐUART INTERRUPT AND  
CLOCK SOURCE REGISTER  
ETI: This bit enables/disables interrupt from the transmitter  
section.  
RBFL: This bit is set when the UART has received a com-  
plete character and has copied it into the RBUF register. It  
is automatically reset when software reads the character  
from RBUF.  
e
e
ETI  
ETI  
0
1
Interrupt from the transmitter is disabled.  
Interrupt from the transmitter is enabled.  
ERI: This bit enables/disables interrupt from the receiver  
section.  
ERR: This bit is a global UART error flag which gets set if  
any or a combination of the errors (DOE, FE, PE) occur.  
e
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ERI  
ERI  
0
1
Interrupt from the receiver is disabled.  
Interrupt from the receiver is enabled.  
CHL1, CHL0: These bits select the character frame format.  
Parity is not included and is generated/verified by hardware.  
XTCLK: This bit selects the clock source for the transmitter-  
section.  
e
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CHL1  
CHL1  
0, CHL0  
0, CHL0  
0
1
The frame contains eight data bits.  
The frame contains seven data  
bits.  
e
XTCLK  
0
1
The clock source is selected through the  
PSR and BAUD registers.  
Signal on CKX (L1) pin is used as the clock.  
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CHL1  
CHL1  
1, CHL0  
1, CHL0  
0
1
The frame contains nine data bits.  
Loopback Mode selected. Trans-  
mitter output internally looped  
back to receiver input. Nine bit  
framing format is used.  
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XTCLK  
XRCLK: This bit selects the clock source for the receiver  
section.  
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XRCLK  
0
The clock source is selected through the  
PSR and BAUD registers.  
Signal on CKX (L1) pin is used as the clock.  
XBIT9/PSEL0: Programs the ninth bit for transmission  
when the UART is operating with nine data bits per frame.  
For seven or eight data bits per frame, this bit in conjunction  
with PSEL1 selects parity.  
XRCLK  
1
SSEL: UART mode select.  
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SSEL  
SSEL  
0
1
Asynchronous Mode.  
Synchronous Mode.  
PSEL1, PSEL0: Parity select bits.  
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PSEL1  
PSEL1  
0, PSEL0  
0, PSEL0  
0
1
Odd Parity (if Parity enabled)  
Even Parity (if Parity enabled)  
17  
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when a framing error occurs and goes low once RDX goes  
high. TBMT, XMTG, RBFL and RCVG are read only bits.  
UART (Continued)  
ETDX: TDX (UART Transmit Pin) is the alternate function  
assigned to Port L pin L2; it is selected by setting ETDX bit.  
To simulate line break generation, software should reset  
ETDX bit and output logic zero to TDX pin through Port L  
data and configuration registers.  
SYNCHRONOUS MODE  
In this mode data is transferred synchronously with the  
clock. Data is transmitted on the rising edge and received  
on the falling edge of the synchronous clock.  
STP78: This bit is set to program the last Stop bit to be  
7/8th of a bit in length.  
This mode is selected by setting SSEL bit in the ENUI regis-  
ter. The input frequency to the UART is the same as the  
baud rate.  
STP2: This bit programs the number of Stop bits to be trans-  
mitted.  
When an external clock input is selected at the CKX pin,  
data transmit and receive are performed synchronously with  
this clock through TDX/RDX pins.  
e
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STP2  
STP2  
0
1
One Stop bit transmitted.  
Two Stop bits transmitted.  
If data transmit and receive are selected with the CKX pin  
as clock output, the device generates the synchronous  
clock output at the CKX pin. The internal baud rate genera-  
tor is used to produce the synchronous clock. Data transmit  
and receive are performed synchronously with this clock.  
Associated I/O Pins  
Data is transmitted on the TDX pin and received on the RDX  
pin. TDX is the alternate function assigned to Port L pin L2;  
it is selected by setting ETDX (in the ENUI register) to one.  
RDX is an inherent function of Port L pin L3, requiring no  
setup.  
FRAMING FORMATS  
The UART supports several serial framing formats (Figure  
12). The format is selected using control bits in the ENU,  
ENUR and ENUI registers.  
The baud rate clock for the UART can be generated on-  
chip, or can be taken from an external source. Port L pin L1  
(CKX) is the external clock I/O pin. The CKX pin can be  
either an input or an output, as determined by Port L Config-  
uration and Data registers (Bit 1). As an input, it accepts a  
clock signal which may be selected to drive the transmitter  
and/or receiver. As an output, it presents the internal Baud  
Rate Generator output.  
The first format (1, 1a, 1b, 1c) for data transmission (CHL0  
e
0) consists of Start bit, seven Data bits (ex-  
e
1, CHL1  
cluding parity) and 7/8, one or two Stop bits. In applications  
using parity, the parity bit is generated and verified by hard-  
ware.  
e
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0) consists of one  
The second format (CHL0  
0, CHL1  
Start bit, eight Data bits (excluding parity) and 7/8, one or  
two Stop bits. Parity bit is generated and verified by hard-  
ware.  
UART Operation  
The UART has two modes of operation: asynchronous  
mode and synchronous mode.  
e
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1)  
The third format for transmission (CHL0  
0, CHL1  
ASYNCHRONOUS MODE  
consists of one Start bit, nine Data bits and 7/8, one or two  
Stop bits. This format also supports the UART ‘‘ATTEN-  
TION’’ feature. When operating in this format, all eight bits  
of TBUF and RBUF are used for data. The ninth data bit is  
transmitted and received using two bits in the ENU and  
ENUR registers, called XBIT9 and RBIT9. RBIT9 is a read  
only bit. Parity is not generated or verified in this mode.  
This mode is selected by resetting the SSEL (in the ENUI  
register) bit to zero. The input frequency to the UART is 16  
times the baud rate.  
The TSFT and TBUF registers double-buffer data for trans-  
mission. While TSFT is shifting out the current character on  
the TDX pin, the TBUF register may be loaded by software  
with the next byte to be transmitted. When TSFT finishes  
transmitting the current character the contents of TBUF are  
transferred to the TSFT register and the Transmit Buffer  
Empty Flag (TBMT in the ENU register) is set. The TBMT  
flag is automatically reset by the UART when software loads  
a new character into the TBUF register. There is also the  
XMTG bit which is set to indicate that the UART is transmit-  
ting. This bit gets reset at the end of the last frame (end of  
last Stop bit). TBUF is a read/write register.  
For any of the above framing formats, the last Stop bit can  
be programmed to be 7/8th of a bit in length. If two Stop  
bits are selected and the 7/8th bit is set (selected), the  
second Stop bit will be 7/8th of a bit in length.  
The parity is enabled/disabled by PEN bit located in the  
ENU register. Parity is selected for 7- and 8-bit modes only.  
e
If parity is enabled (PEN  
1), the parity selection is then  
performed by PSEL0 and PSEL1 bits located in the ENU  
register.  
The RSFT and RBUF registers double-buffer data being re-  
ceived. The UART receiver continually monitors the signal  
on the RDX pin for a low level to detect the beginning of a  
Start bit. Upon sensing this low level, it waits for half a bit  
time and samples again. If the RDX pin is still low, the re-  
ceiver considers this to be a valid Start bit, and the remain-  
ing bits in the character frame are each sampled a single  
time, at the mid-bit position. Serial data input on the RDX pin  
is shifted into the RSFT register. Upon receiving the com-  
plete character, the contents of the RSFT register are cop-  
ied into the RBUF register and the Received Buffer Full Flag  
(RBFL) is set. RBFL is automatically reset when software  
reads the character from the RBUF register. RBUF is a read  
only register. There is also the RCVG bit which is set high  
Note that the XBIT9/PSEL0 bit located in the ENU register  
serves two mutually exclusive functions. This bit programs  
the ninth bit for transmission when the UART is operating  
with nine data bits per frame. There is no parity selection in  
this framing format. For other framing formats XBIT9 is not  
needed and the bit is PSEL0 used in conjunction with  
PSEL1 to select parity.  
The frame formats for the receiver differ from the transmit-  
ter in the number of Stop bits required. The receiver only  
requires one Stop bit in a frame, regardless of the setting of  
the Stop bit selection bits in the control register. Note that  
an implicit assumption is made for full duplex UART opera-  
tion that the framing formats are the same for the transmit-  
ter and receiver.  
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18  
UART Operation (Continued)  
TL/DD/976519  
FIGURE 12. Framing Formats  
UART INTERRUPTS  
source selected in the PSR and BAUD registers. Internally,  
the basic baud clock is created from the oscillator frequency  
through a two-stage divider chain consisting of a 116 (in-  
crements of 0.5) prescaler and an 11-bit binary counter.  
(Figure 13) The divide factors are specified through two  
read/write registers shown in Figure 14. Note that the 11-bit  
Baud Rate Divisor spills over into the Prescaler Select Reg-  
ister (PSR). PSR is cleared upon reset.  
The UART is capable of generating interrupts. Interrupts are  
generated on Receive Buffer Full and Transmit Buffer Emp-  
ty. Both interrupts have individual interrupt vectors. Two  
bytes of program memory space are reserved for each inter-  
rupt vector. The two vectors are located at addresses 0xEC  
to 0xEF Hex in the program memory space. The interrupts  
can be individually enabled or disabled using Enable Trans-  
mit Interrupt (ETI) and Enable Receive Interrupt (ERI) bits in  
the ENUI register.  
As shown in Table I, a Prescaler Factor of 0 corresponds to  
NO CLOCK. NO CLOCK condition is the UART power down  
mode where the UART clock is turned off for power saving  
purpose. The user must also turn the UART clock off when  
a different baud rate is chosen.  
The interrupt from the Transmitter is set pending, and re-  
mains pending, as long as both the TBMT and ETI bits are  
set. To remove this interrupt, software must either clear the  
ETI bit or write to the TBUF register (thus clearing the TBMT  
bit).  
The correspondences between the 5-bit Prescaler Select  
and Prescaler factors are shown in Table I. Therer are many  
ways to calculate the two divisor factors, but one particularly  
effective method would be to achieve a 1.8432 MHz fre-  
quency coming out of the first stage. The 1.8432 MHz pre-  
scaler output is then used to drive the software programma-  
ble baud rate counter to create a x16 clock for the following  
baud rates: 110, 134.5, 150, 300, 600, 1200, 1800, 2400,  
3600, 4800, 7200, 9600, 19200 and 38400 (Table II). Other  
baud rates may be created by using appropriate divisors.  
The x16 clock is then divided by 16 to provide the rate for  
the serial shift registers of the transmitter and receiver.  
The interrupt from the receiver is set pending, and remains  
pending, as long as both the RBFL and ERI bits are set. To  
remove this interrupt, software must either clear the ERI bit  
or read from the RBUF register (thus clearing the RBFL bit).  
Baud Clock Generation  
The clock inputs to the transmitter and receiver sections of  
the UART can be individually selected to come either from  
an external source at the CKX pin (port L, pin L1) or from a  
19  
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Baud Clock Generation (Continued)  
TL/DD/976520  
FIGURE 13. UART BAUD Clock Generation  
TL/DD/976521  
FIGURE 14. UART BAUD Clock Divisor Registers  
TABLE I. Prescaler Factors  
TABLE II. Baud Rate Divisors  
(1.8432 MHz Prescaler Output)  
Prescaler  
Select  
Prescaler  
Factor  
Baud  
Rate  
Baud Rate  
b
Divisor 1 (N-1)  
00000  
00001  
00010  
00011  
00100  
00101  
00110  
00111  
01000  
01001  
01010  
01011  
01100  
01101  
01110  
01111  
10000  
10001  
10010  
10011  
10100  
10101  
10110  
10111  
11000  
11001  
11010  
11011  
11100  
11101  
11110  
11111  
NO CLOCK  
1
110 (110.03)  
134.5 (134.58)  
150  
1046  
855  
767  
383  
191  
95  
1.5  
2
300  
2.5  
3
600  
1200  
3.5  
4
1800  
63  
2400  
47  
4.5  
5
3600  
31  
4800  
23  
5.5  
6
7200  
15  
9600  
11  
6.5  
7
19200  
38400  
5
2
7.5  
8
The entries in Table II assume a prescaler output  
of 1.8432 MHz. In the asynchronous mode the  
baud rate could be as high as 625k.  
8.5  
9
As an example, considering the Asynchronous Mode and a  
CKI clock of 4.608 MHz, the prescaler factor selected is:  
9.5  
10  
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4.608/1.8432  
2.5  
10.5  
11  
The 2.5 entry is available in Table I. The 1.8432 MHz pre-  
scaler output is then used with proper Baud Rate Divisor  
(Table II) to obtain different baud rates. For a baud rate of  
19200 e.g., the entry in Table II is 5.  
11.5  
12  
12.5  
13  
b
e
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b
5 (N 1 is the value from Table II)  
N
1
N
6 (N is the Baud Rate Divisor)  
13.5  
14  
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1.8432 MHz/(16 6) 19200  
Baud Rate  
The divide by 16 is performed because in the asynchronous  
mode, the input frequency to the UART is 16 times the baud  
rate. The equation to calculate baud rates is given below.  
14.5  
15  
15.5  
16  
The actual Baud Rate may be found from:  
e
c
c
N P)  
BR  
Fc/(16  
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20  
Note that the framing format for this mode is the nine bit  
format; one Start bit, nine data bits, and 7/8, one or two  
Stop bits. Parity is not generated or verified in this mode.  
Baud Clock Generation (Continued)  
Where:  
BR is the Baud Rate  
Fc is the CKI frequency  
Attention Mode  
N is the Baud Rate Divisor (Table II).  
The UART Receiver section supports an alternate mode of  
operation, referred to as ATTENTION Mode. This mode of  
operation is selected by the ATTN bit in the ENUR register.  
The data format for transmission must also be selected as  
having nine Data bits and either 7/8, one or two Stop bits.  
P is the Prescaler Divide Factor selected by the value in the  
Prescaler Select Register (Table I)  
Note: In the Synchronous Mode, the divisor 16 is replaced by two.  
Example:  
The ATTENTION mode of operation is intended for use in  
networking the device with other processors. Typically in  
such environments the messages consists of device ad-  
dresses, indicating which of several destinations should re-  
ceive them, and the actual data. This Mode supports a  
scheme in which addresses are flagged by having the ninth  
bit of the data field set to a 1. If the ninth bit is reset to a  
zero the byte is a Data byte.  
Asynchronous Mode:  
e
e
Crystal Frequency  
Desired baud rate  
5 MHz  
9600  
c
Using the above equation N  
6
P can be calculated first.  
c
e
c c  
(5 10 )/(16 9600) 32.552  
e
N
P
Now 32.552 is divided by each Prescaler Factor (Table II) to  
obtain a value closest to an integer. This factor happens to  
While in ATTENTION mode, the UART monitors the com-  
munication flow, but ignores all characters until an address  
character is received. Upon receiving an address character,  
the UART signals that the character is ready by setting the  
RBFL flag, which in turn interrupts the processor if UART  
Receiver interrupts are enabled. The ATTN bit is also  
cleared automatically at this point, so that data characters  
as well as address characters are recognized. Software ex-  
amines the contents of the RBUF and responds by deciding  
either to accept the subsequent data stream (by leaving the  
ATTN bit reset) or to wait until the next address character is  
seen (by setting the ATTN bit again).  
e
be 6.5 (P  
6.5).  
e
e
e
5.008 (N 5)  
N
32.552/6.5  
b
The programmed value (from Table II) should be 4 (N  
1).  
Using the above values calculated for N and P:  
6
e
c
(5 10 )/(16  
c
c
e
6.5) 9615.384  
BR  
5
e
b
e
(9615.385 9600)/9600 0.16  
% error  
Effect of HALT/IDLE  
The UART logic is reinitialized when either the HALT or  
IDLE modes are entered. This reinitialization sets the TBMT  
flag and resets all read only bits in the UART control and  
status registers. Read/Write bits remain unchanged. The  
Transmit Buffer (TBUF) is not affected, but the Transmit  
Shift register (TSFT) bits are set to one. The receiver regis-  
ters RBUF and RSFT are not affected.  
Operation of the UART Transmitter is not affected by selec-  
tion of this Mode. The value of the ninth bit to be transmitted  
is programmed by setting XBIT9 appropriately. The value of  
the ninth bit received is obtained by reading RBIT9. Since  
this bit is located in ENUR register where the error flags  
reside, a bit operation on it will reset the error flags.  
The device will exit from the HALT/IDLE modes when the  
Start bit of a character is detected at the RDX (L3) pin. This  
feature is obtained by using the Multi-Input Wakeup scheme  
provided on the device.  
Comparators  
The device contains two differential comparators, each with  
a pair of inputs (positive and negative) and an output. Ports  
I1I3 and I4I6 are used for the comparators. The following  
is the Port I assignment:  
Before entering the HALT or IDLE modes the user program  
must select the Wakeup source to be on the RDX pin. This  
selection is done by setting bit 3 of WKEN (Wakeup Enable)  
register. The Wakeup trigger condition is then selected to  
be high to low transition. This is done via the WKEDG regis-  
ter (Bit 3 is one.)  
I1 Comparator1 negative input  
I2 Comparator1 positive input  
I3 Comparator1 output  
If the device is halted and crystal oscillator is used, the  
Wakeup signal will not start the chip running immediately  
because of the finite start up time requirement of the crystal  
I4 Comparator2 negative input  
I5 Comparator2 positive input  
I6 Comparator2 output  
oscillator. The idle timer (T0) generates a fixed (256 t ) de-  
c
A Comparator Select Register (CMPSL) is used to enable  
the comparators, read the outputs of the comparators inter-  
nally, and enable the outputs of the comparators to the pins.  
Two control bits (enable and output enable) and one result  
bit are associated with each comparator. The comparator  
result bits (CMP1RD and CMP2RD) are read only bits which  
will read as zero if the associated comparator is not en-  
abled. The Comparator Select Register is cleared with  
reset, resulting in the comparators being disabled. The com-  
parators should also be disabled before entering either the  
HALT or IDLE modes in order to save power. The configura-  
tion of the CMPSL register is as follows:  
lay to ensure that the oscillator has indeed stabilized before  
allowing the device to execute code. The user has to con-  
sider this delay when data transfer is expected immediately  
after exiting the HALT mode.  
Diagnostic  
Bits CHARL0 and CHARL1 in the ENU register provide a  
loopback feature for diagnostic testing of the UART. When  
these bits are set to one, the following occur: The receiver  
input pin (RDX) is internally connected to the transmitter  
output pin (TDX); the output of the Transmitter Shift Regis-  
ter is ‘‘looped back’’ into the Receive Shift Register input. In  
this mode, data that is transmitted is immediately received.  
This feature allows the processor to verify the transmit and  
receive data paths of the UART.  
21  
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Comparators (Continued)  
Interrupts  
The device supports a vectored interrupt scheme. It sup-  
ports a total of fourteen interrupt sources. The following ta-  
ble lists all the possible device interrupt sources, their arbi-  
tration ranking and the memory locations reserved for the  
interrupt vector for each source.  
CMPSL REGISTER (ADDRESS X’00B7)  
The CMPSL register contains the following bits:  
CMP1EN Enable comparator 1  
CMP1RD Comparator 1 result (this is a read only bit,  
which will read as 0 if the comparator is not  
enabled)  
Two bytes of program memory space are reserved for each  
interrupt source. All interrupt sources except the software  
interrupt are maskable. Each of the maskable interrupts  
have an Enable bit and a Pending bit. A maskable interrupt  
is active if its associated enable and pending bits are set. If  
CMP10E  
Selects pin I3 as comparator 1 output provided  
that CMPIEN is set to enable the comparator  
CMP2EN  
CMP2RD  
Enable comparator 2  
e
GIE  
1 and an interrupt is active, then the processor will  
Comparator 2 result (this is a read only bit,  
which will read as 0 if the comparator is not  
enabled)  
be interrupted as soon as it is ready to start executing an  
instruction except if the above conditions happen during the  
Software Trap service routine. This exception is described  
in the Software Trap sub-section.  
CMP20E  
Selects pin I6 as comparator 2 output provided  
that CMP2EN is set to enable the comparator  
The interruption process is accomplished with the INTR in-  
struction (opcode 00), which is jammed inside the Instruc-  
tion Register and replaces the opcode about to be execut-  
ed. The following steps are performed for every interrupt:  
Unused CMP20E CMP2RD CMP2EN CMP10E CMP1RD CMP1EN Unused  
Bit 7 Bit 0  
Note that the two unused bits of CMPSL may be used as  
software flags.  
1. The GIE (Global Interrupt Enable) bit is reset.  
2. The address of the instruction about to be executed is  
pushed into the stack.  
Comparator outputs have the same spec as Ports L and G  
except that the rise and fall times are symmetrical.  
3. The PC (Program Counter) branches to address 00FF.  
This procedure takes 7 t cycles to execute.  
c
TL/DD/976522  
FIGURE 15. Interrupt Block Diagram  
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22  
Interrupts (Continued)  
Vector  
Address  
Arbitration  
Source  
Description  
Ranking  
Hi-Low Byte  
(1) Highest  
Software  
INTR Instruction  
for Future Use  
Pin G0 Edge  
Underflow  
0yFE0yFF  
0yFC0yFD  
0yFA0yFB  
0yF80yF9  
0yF60yF7  
0yF40yF5  
0yF20yF3  
0yF00yF1  
0yEE0yEF  
0yEC0yED  
0yEA0yEB  
0yE80yE9  
0yE60yE7  
0yE40yE5  
0yE20yE3  
0yE00yE1  
Reserved  
External  
(2)  
(3)  
(4)  
(5)  
(6)  
Timer T0  
Timer T1  
Timer T1  
MICROWIRE/PLUS  
Reserved  
UART  
T1A/Underflow  
T1B  
BUSY Goes Low  
for Future Use  
Receive  
(7)  
(8)  
UART  
Transmit  
(9)  
Timer T2  
Timer T2  
Timer T3  
Timer T3  
Port L/Wakeup  
Default  
T2A/Underflow  
T2B  
(10)  
(11)  
T3A/Underflow  
T3B  
(12)  
(13)  
Port L Edge  
(14) Lowest  
VIS Instr. Execution  
without Any Interrupts  
i
y is VIS page, y  
0.  
e
At this time, since GIE  
0, other maskable interrupts are  
a table starting at 01E0 (assuming that VIS is located be-  
tween 00FF and 01DF). The vectors are 15-bit wide and  
therefore occupy 2 ROM locations.  
disabled. The user is now free to do whatever context  
switching is required by saving the context of the machine in  
the stack with PUSH instructions. The user would then pro-  
gram a VIS (Vector Interrupt Select) instruction in order to  
branch to the interrupt service routine of the highest priority  
interrupt enabled and pending at the time of the VIS. Note  
that this is not necessarily the interrupt that caused the  
branch to address location 00FF Hex prior to the context  
switching.  
VIS and the vector table must be located in the same 256-  
byte block (0y00 to 0yFF) except if VIS is located at the last  
address of a block. In this case, the table must be in the  
next block. The vector table cannot be inserted in the first  
i
256-byte block (y  
0).  
The vector of the maskable interrupt with the lowest rank is  
located at 0yE0 (Hi-Order byte) and 0yE1 (Lo-Order byte)  
and so forth in increasing rank number. The vector of the  
maskable interrupt with the highest rank is located at 0yFA  
(Hi-Order byte) and 0yFB (Lo-Order byte).  
Thus, if an interrupt with a higher rank than the one which  
caused the interruption becomes active before the decision  
of which interrupt to service is made by the VIS, then the  
interrupt with the higher rank will override any lower ones  
and will be acknowledged. The lower priority interrupt(s) are  
still pending, however, and will cause another interrupt im-  
mediately following the completion of the interrupt service  
routine associated with the higher priority interrupt just serv-  
iced. This lower priority interrupt will occur immediately fol-  
lowing the RETI (Return from Interrupt) instruction at the  
end of the interrupt service routine just completed.  
The Software Trap has the highest rank and its vector is  
located at 0yFE and 0yFF.  
If, by accident, a VIS gets executed and no interrupt is ac-  
tive, then the PC (Program Counter) will branch to a vector  
located at 0yE00yE1.  
WARNING; A Default VIS interrupt handler routine must be  
present. As a minimum, this handler should confirm that the  
GIE bit is cleared (this indicates that the interrupt sequence  
has been taken), take care of any required housekeeping,  
restore context and return. Some sort of Warm Restart pro-  
cedure should be implemented. These events can occur  
without any error on the part of the system designer or pro-  
grammer.  
Inside the interrupt service routine, the associated pending  
bit has to be cleared by software. The RETI (Return from  
Interrupt) instruction at the end of the interrupt service rou-  
tine will set the GIE (Global Interrupt Enable) bit, allowing  
the processor to be interrupted again if another interrupt is  
active and pending.  
Note: There is always the possibility of an interrupt occurring during an in-  
struction which is attempting to reset the GIE bit or any other interrupt  
enable bit. If this occurs when a single cycle instruction is being used  
to reset the interrupt enable bit, the interrupt enable bit will be reset  
but an interrupt may still occur. This is because interrupt processing is  
started at the same time as the interrupt bit is being reset. To avoid  
this scenario, the user should always use a two, three, or four cycle  
instruction to reset interrupt enable bits.  
The VIS instruction looks at all the active interrupts at the  
time it is executed and performs an indirect jump to the  
beginning of the service routine of the one with the highest  
rank.  
The addresses of the different interrupt service routines,  
called vectors, are chosen by the user and stored in ROM in  
Figure 15 shows the Interrupt block diagram.  
23  
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TABLE IV. WATCHDOG Service Window Select  
Interrupts (Continued)  
WDSVR  
Bit 7  
WDSVR  
Bit 6  
Service Window  
SOFTWARE TRAP  
(Lower-Upper Limits)  
The Software Trap (ST) is a special kind of non-maskable  
interrupt which occurs when the INTR instruction (used to  
acknowledge interrupts) is fetched from ROM and placed  
inside the instruction register. This may happen when the  
PC is pointing beyond the available ROM address space or  
when the stack is over-popped.  
0
0
1
1
0
1
0
1
2k8k t Cycles  
c
2k16k t Cycles  
c
2k32k t Cycles  
c
2k64k t Cycles  
c
When an ST occurs, the user can re-initialize the stack  
pointer and do a recovery procedure (similar to reset, but  
not necessarily containing all of the same initialization pro-  
cedures) before restarting.  
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/t ) is greater or equal to 10 kHz. This equates to a  
c
clock input rate on CKI of greater or equal to 100 kHz.  
The occurrence of an ST is latched into the ST pending bit.  
The GIE bit is not affected and the ST 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. The RPND instruction is used to clear the  
software interrupt pending bit. This pending bit is also  
cleared on reset.  
WATCHDOG Operation  
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.  
The ST has the highest rank among all interrupts.  
Nothing (except another ST) can interrupt an ST being  
serviced.  
WATCHDOG  
The device contains a WATCHDOG and clock monitor. The  
WATCHDOG is designed to detect the user program getting  
stuck in infinite loops resulting in loss of program control or  
‘‘runaway’’ programs. The Clock Monitor is used to detect  
the absence of a clock or a very slow clock below a speci-  
fied rate on the CKI pin.  
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-  
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 V shows the se-  
quence of events that can occur.  
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 val-  
ue 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 III shows the WDSVR register.  
The user must service the WATCHDOG at least once be-  
fore the upper limit of the service window expires. The  
WATCHDOG 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.  
The lower limit of the service window is fixed at 2048 in-  
struction cycles. Bits 7 and 6 of the WDSVR register allow  
the user to pick an upper limit of the service window.  
Table IV shows the four possible combinations of lower and  
upper limits for the WATCHDOG service window. This flexi-  
bility in choosing the WATCHDOG service window prevents  
any undue burden on the user software.  
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. The WDOUT pin is in the high impedance state in the  
inactive state. Upon triggering the WATCHDOG, the logic  
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.  
will pull the WDOUT (G1) pin low for an additional 16 t –  
c
32 t cycles after the signal level on WDOUT pin goes be-  
c
TABLE III. WATCHDOG Service Register (WDSVR)  
low the lower Schmitt trigger threshold. After this delay, the  
device will stop forcing the WDOUT output low.  
Window  
Select  
Clock  
Key Data  
Monitor  
X
X
6
0
5
1
4
1
3
0
2
0
1
Y
0
7
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24  
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.  
#
WATCHDOG Operation (Continued)  
The WATCHDOG service window will restart when the  
WDOUT pin goes high. It is recommended that the user tie  
through a resistor in order to  
the WDOUT pin back to V  
pull WDOUT high.  
CC  
The WATCHDOG detector circuit is inhibited during both  
the HALT and IDLE modes.  
#
#
A WATCHDOG service while the WDOUT signal is active  
will be ignored. The state of the WDOUT pin is not guaran-  
teed on reset, but if it powers up low then the WATCHDOG  
will time out and WDOUT will enter high impedance state.  
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 detect-  
ed as a CLOCK MONITOR error (provided that the  
CLOCK MONITOR enable option has been selected by  
the program).  
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 speci-  
fied value, after which the G1 output will enter the high im-  
With the single-pin R/C oscillator mask option selected  
and the CLKDLY bit reset, the WATCHDOG service win-  
dow will resume following HALT mode from where it left  
off before entering the HALT mode.  
#
#
pedance TRI-STATE mode following 16 t 32 t clock cy-  
c
c
cles. The Clock Monitor generates a continual Clock Moni-  
tor error if the oscillator fails to start, or fails to reach the  
minimum specified frequency. The specification for the  
Clock Monitor is as follows:  
With the crystal oscillator mask option selected, or with  
the single-pin R/C oscillator mask option selected and  
the CLKDLY bit set, the WATCHDOG service window will  
be set to its selected value from WDSVR following HALT.  
Consequently, the WATCHDOG should not be serviced  
for at least 2048 instruction cycles following HALT, but  
must be serviced within the selected window to avoid a  
WATCHDOG error.  
l
k
1/t  
10 kHzÐNo clock rejection.  
c
c
1/t  
10 HzÐGuaranteed clock rejection.  
Watchdog and Clock Monitor  
Summary  
The following salient points regarding the WATCHDOG and  
The IDLE timer T0 is not initialized with 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 thirteenth bit of  
the IDLE counter toggles (every 4096 instruction cycles).  
The user is responsible for resetting the T0PND flag.  
CLOCK MONITOR should be noted:  
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 he  
maximum service window selected.  
#
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 2048 instruction  
cycles following IDLE, but must be serviced within the  
selected window to avoid a WATCHDOG error.  
#
#
The WATCHDOG service window and CLOCK MONI-  
TOR enable/disable option can only be changed once,  
during the initial WATCHDOG service following RESET.  
#
The initial WATCHDOG service must match the key data  
value in the WATCHDOG Service register WDSVR in or-  
der to avoid a WATCHDOG error.  
#
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 ini-  
tial WATCHDOG service may be programmed within the  
initial 2048 instruction cycles without causing a WATCH-  
DOG error.  
Subsequent WATCHDOG services must match all three  
data fields in WDSVR in order to avoid WATCHDOG er-  
rors.  
#
25  
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Detection of Illegal Conditions  
MICROWIRE/PLUS  
The device can detect various illegal conditions resulting  
from coding errors, transient noise, power supply voltage  
drops, runaway programs, etc.  
MICROWIRE/PLUS is a serial synchronous communica-  
tions interface. The MICROWIRE/PLUS capability enables  
the device to interface with any of National Semiconductor’s  
MICROWIRE peripherals (i.e. A/D converters, display driv-  
Reading of undefined ROM gets zeros. The opcode for soft-  
ware interrupt is zero. If the program fetches instructions  
from undefined ROM, this will force a software interrupt,  
thus signaling that an illegal condition has occurred.  
2
ers, E PROMs etc.) and with other microcontrollers which  
support the MICROWIRE 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 12  
shows a block diagram of the MICROWIRE/PLUS logic.  
The subroutine stack grows down for each call (jump to  
subroutine), interrupt, or PUSH, and grows up for each re-  
turn 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), 140 to 17F  
(Segment 1), and all other segments (i.e., Segments 3 . . .  
etc.) is read as all 1’s, which in turn will cause the program  
to return to address 7FFF Hex. This is an undefined ROM  
location and the instruction fetched (all 0’s) from this loca-  
tion will generate a software interrupt signaling an illegal  
condition.  
Thus, the chip can detect the following illegal conditions:  
a. Executing from undefined ROM  
TL/DD/976523  
b. Over ‘‘POP’’ing the stack by having more returns than  
calls.  
FIGURE 16. MICROWIRE/PLUS Block Diagram  
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.  
When the software interrupt occurs, the user can re-initialize  
the stack pointer and do a recovery procedure before re-  
starting (this recovery program is probably similar to that  
following reset, but might not contain the same program  
initialization procedures). The recovery program should re-  
set the software interrupt pending bit using the RPND in-  
struction.  
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 VI details the  
different clock rates that may be selected.  
TABLE V. WATCHDOG Service Actions  
Key  
Window  
Data  
Clock  
Action  
Data  
Monitor  
Match  
Match  
Match  
Valid Service: Restart Service Window  
Error: Generate WATCHDOG Output  
Error: Generate WATCHDOG Output  
Error: Generate WATCHDOG Output  
Don’t Care  
Mismatch  
Don’t Care  
Mismatch  
Don’t Care  
Don’t Care  
Don’t Care  
Don’t Care  
Mismatch  
TABLE VI. MICROWIRE/PLUS  
Master Mode Clock Select  
SL1  
SL0  
SK  
Where t is the  
c
instruction cycle clock  
c
c
c
0
0
1
0
1
x
2
4
8
t
c
t
c
t
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26  
MICROWIRE/PLUS (Continued)  
MICROWIRE/PLUS OPERATION  
The user must set the BUSY flag immediately upon entering  
the Slave mode. This will ensure that all data bits sent by  
the Master will be shifted properly. After eight clock pulses  
the BUSY flag will be cleared and the sequence may be  
repeated.  
Setting the BUSY bit in the PSW register causes the MI-  
CROWIRE/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 13 shows  
how two devices, microcontrollers and several peripherals  
may be interconnected using the MICROWIRE/PLUS ar-  
rangements.  
Alternate SK Phase Operation  
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 is normally low. 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 shift-  
ed in on the falling edge of the SK clock and shifted out on  
the rising edge of the SK clock.  
Warning:  
The SIO register should only be loaded when the SK clock  
is low. Loading the SIO register while the SK clock is high  
will result in undefined data in the SIO register. SK clock is  
normally low when not shifting.  
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 configura-  
tion bit. The SKSEL flag will power up in the reset condition,  
selecting the normal SK signal.  
Setting the BUSY flag when the input SK clock is high in the  
MICROWIRE/PLUS slave 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  
low.  
MICROWIRE/PLUS Master Mode Operation  
TABLE VII  
In the MICROWIRE/PLUS Master mode of operation the  
shift clock (SK) is generated internally. The MICROWIRE  
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. Table VII summarizes the bit settings  
required for Master mode of operation.  
This table assumes that the control flag MSEL is set.  
G4 (SO)  
G5 (SK)  
G4  
G5  
Operation  
Config. Bit Config. Bit Fun. Fun.  
1
0
1
0
1
1
0
0
SO  
Int. MICROWIRE/PLUS  
SK Master  
TRI- Int. MICROWIRE/PLUS  
STATE SK Master  
MICROWIRE/PLUS Slave Mode Operation  
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 bit in the Port G configuration reg-  
ister. Table VII summarizes the settings required to enter  
the Slave mode of operation.  
SO  
Ext. MICROWIRE/PLUS  
SK Slave  
TRI- Ext. MICROWIRE/PLUS  
STATE SK Slave  
TL/DD/976524  
FIGURE 17. MICROWIRE/PLUS Application  
27  
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Memory Map  
All RAM, ports and registers (except A and PC) are mapped into data memory address space.  
Address  
Address  
Contents  
Contents  
Port L Data Register  
S/ADD REG  
S/ADD REG  
0000 to 006F  
0070 to 007F  
On-Chip RAM bytes (112 bytes)  
xxD0  
xxD1  
Port L Configuration Register  
Port L Input Pins (Read Only)  
Reserved for Port L  
Unused RAM Address Space (Reads  
As All Ones)  
xxD2  
xxD3  
xx80 to xxAF  
Unused RAM Address Space (Reads  
Undefined Data)  
xxD4  
Port G Data Register  
xxD5  
Port G Configuration Register  
Port G Input Pins (Read Only)  
Port I Input Pins (Read Only)  
Port C Data Register  
xxB0  
XXB1  
xxB2  
Timer T3 Lower Byte  
xxD6  
Timer T3 Upper Byte  
xxD7  
Timer T3 Autoload Register T3RA  
Lower Byte  
xxD8  
xxD9  
Port C Configuration Register  
Port C Input Pins (Read Only)  
Reserved for Port C  
xxB3  
xxB4  
xxB5  
Timer T3 Autoload Register T3RA  
Upper Byte  
xxDA  
xxDB  
xxDC  
xxDD to DF  
Timer T3 Autoload Register T3RB  
Lower Byte  
Port D  
Reserved for Port D  
Timer T3 Autoload Register T3RB  
Upper Byte  
xxE0 to xxE5  
xxE6  
Reserved for EE Control Registers  
Timer T1 Autoload Register T1RB  
Lower Byte  
xxB6  
xxB7  
xxB8  
xxB9  
xxBA  
Timer T3 Control Register  
Comparator Select Register (CMPSL)  
UART Transmit Buffer (TBUF)  
UART Receive Buffer (RBUF)  
UART Control and Status Register  
(ENU)  
xxE7  
Timer T1 Autoload Register T1RB  
Upper Byte  
xxE8  
xxE9  
xxEA  
xxEB  
xxEC  
ICNTRL Register  
MICROWIRE/PLUS Shift Register  
Timer T1 Lower Byte  
xxBB  
xxBC  
UART Receive Control and Status  
Register (ENUR)  
Timer T1 Upper Byte  
UART Interrupt and Clock Source  
Register (ENUI)  
Timer T1 Autoload Register T1RA  
Lower Byte  
xxBD  
xxBE  
xxBF  
UART Baud Register (BAUD)  
UART Prescale Select Register (PSR)  
Reserved for UART  
xxED  
Timer T1 Autoload Register T1RA  
Upper Byte  
xxEE  
xxEF  
CNTRL Control Register  
PSW Register  
xxC0  
xxC1  
xxC2  
Timer T2 Lower Byte  
Timer T2 Upper Byte  
Timer T2 Autoload Register T2RA  
Lower Byte  
xxF0 to FB  
xxFC  
On-Chip RAM Mapped as Registers  
X Register  
xxFD  
SP Register  
xxC3  
xxC4  
xxC5  
Timer T2 Autoload Register T2RA  
Upper Byte  
xxFE  
B Register  
xxFF  
S Register  
Timer T2 Autoload Register T2RB  
Lower Byte  
0100013F  
On-Chip 64 RAM Bytes  
Timer T2 Autoload Register T2RB  
Upper Byte  
Reading memory locations 0070H007FH (Segment 0) will return all ones.  
Reading unused memory locations 0080H00AFH (Segment 0) will return  
undefined data. Reading unused memory locations 0140017F (Segment 1)  
will return all ones. Reading memory locations from other Segments (i.e.,  
Segment 2, Segment 3, ... etc.) will return all ones.  
xxC6  
xxC7  
Timer T2 Control Register  
WATCHDOG Service Register  
(Reg:WDSVR)  
xxC8  
MIWU Edge Select Register  
(Reg:WKEDG)  
xxC9  
xxCA  
MIWU Enable Register (Reg:WKEN)  
MIWU Pending Register  
(Reg:WKPND)  
xxCB  
Reserved  
xxCC  
Reserved  
xxCD to xxCF  
Reserved  
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28  
Addressing Modes  
There are ten addressing modes, six for operand address-  
ing and four for transfer of control.  
Indirect  
This mode is used with the JID instruction. The contents of  
the accumulator are used as a partial address (lower 8 bits  
of PC) for accessing a location in the program memory. The  
contents of this program memory location serve as a partial  
address (lower 8 bits of PC) for the jump to the next instruc-  
tion.  
OPERAND ADDRESSING MODES  
Register Indirect  
This is the ‘‘normal’’ addressing mode. The operand is the  
data memory addressed by the B pointer or X pointer.  
Register Indirect (with auto post increment or  
decrement of pointer)  
Note: The VIS is a special case of the Indirect Transfer of Control address-  
ing 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.  
This addressing mode is used with the LD and X instruc-  
tions. The operand is the data memory addressed by the B  
pointer or X pointer. This is a register indirect mode that  
automatically post increments or decrements the B or X reg-  
ister after executing the instruction.  
Instruction Set  
Register and Symbol Definition  
Direct  
The instruction contains an 8-bit address field that directly  
points to the data memory for the operand.  
Registers  
A
8-Bit Accumulator Register  
8-Bit Address Register  
Immediate  
B
The instruction contains an 8-bit immediate field as the op-  
erand.  
X
8-Bit Address Register  
SP  
PC  
PU  
PL  
C
8-Bit Stack Pointer Register  
15-Bit Program Counter Register  
Upper 7 Bits of PC  
Short Immediate  
This addressing mode is used with the Load B Immediate  
instruction. The instruction contains a 4-bit immediate field  
as the operand.  
Lower 8 Bits of PC  
1 Bit of PSW Register for Carry  
1 Bit of PSW Register for Half Carry  
1 Bit of PSW Register for Global  
Interrupt Enable  
Indirect  
HC  
GIE  
This addressing mode is used with the LAID instruction. The  
contents of the accumulator are used as a partial address  
(lower 8 bits of PC) for accessing a data operand from the  
program memory.  
VU  
VL  
Interrupt Vector Upper Byte  
Interrupt Vector Lower Byte  
TRANSFER OF CONTROL ADDRESSING MODES  
Relative  
Symbols  
This mode is used for the JP instruction, with the instruction  
field being added to the program counter to get the new  
[
[
]
B
Memory Indirectly Addressed by B  
Register  
b
a
program location. JP has a range from 31 to 32 to allow  
1 is implemented by a NOP  
a
a 1-byte relative jump (JP  
]
X
Memory Indirectly Addressed by X  
Register  
instruction). There are no ‘‘pages’’ when using JP, since all  
15 bits of PC are used.  
MD  
Direct Addressed Memory  
[
[
]
]
Mem  
Meml  
Direct Addressed Memory or  
Direct Addressed Memory or  
Immediate Data  
B
Absolute  
B
or  
This mode is used with the JMP and JSR instructions, with  
the instruction field of 12 bits replacing the lower 12 bits of  
the program counter (PC). This allows jumping to any loca-  
tion in the current 4k program memory segment.  
Imm  
Reg  
8-Bit Immediate Data  
Register Memory: Addresses F0 to FF  
(Includes B, X and SP)  
Bit Number (0 to 7)  
Absolute Long  
Bit  
This mode is used with the JMPL and JSRL instructions,  
with the instruction field of 15 bits replacing the entire 15  
bits of the program counter (PC). This allows jumping to any  
location in the current 4k program memory space.  
w
Ý
Loaded with  
Exchanged with  
29  
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Instruction Set (Continued)  
INSTRUCTION SET  
a
a
ADD  
ADC  
A,Meml  
A,Meml  
ADD  
ADD with Carry  
w
Meml  
Meml  
AwA  
w
A
C, C  
C, C  
w
w
Carry  
Carry  
a
A
HC  
Half Carry  
b
a
SUBC  
A,Meml  
Subtract with Carry  
A
w
A
MemI  
Half Carry  
A and Meml  
HC  
A
w
AND  
A,Meml  
A,Imm  
A,Meml  
A,Meml  
MD,Imm  
A,Meml  
A,Meml  
A,Meml  
Ý
Logical AND  
Logical AND Immed., Skip if Zero  
Logical OR  
Logical EXclusive OR  
IF EQual  
IF EQual  
w
e
0
ANDSZ  
OR  
XOR  
Skip next if (A and Imm)  
AwAA xoor rMMeemml l  
w
A
Compare MD and Imm, Do next if MD  
e
Imm  
Meml  
IFEQ  
IFEQ  
IFNE  
IFGT  
IFBNE  
DRSZ  
SBIT  
RBIT  
IFBIT  
RPND  
e
Compare A and Meml, Do next if A  
i
Compare A and Meml, Do next if A Meml  
l
Compare A and Meml, Do next if A Meml  
i
Do next if lower 4 bits of B Imm  
IF Not Equal  
IF Greater Than  
If B Not Equal  
Decrement Reg., Skip if Zero  
Set BIT  
Reset BIT  
IF BIT  
Reset PeNDing Flag  
b
e
0
0 to 7 immediate)  
Reg  
Reg  
w
Reg 1, Skip if Reg  
1 to bit, Mem (bit  
0 to bit, Mem  
e
Ý
Ý
Ý
,Mem  
,Mem  
,Mem  
If bit in A or Mem is true do next instruction  
Reset Software Interrupt Pending Flag  
X
X
A,Mem  
EXchange A with Memory  
EXchange A with Memory  
LoaD A with Memory  
A
Ý
Ý
Mem  
[ ]  
X
[
A, X  
A,Meml  
]
[
]
X
LD  
LD  
LD  
LD  
LD  
A
AwMeml  
[
A, X  
B,Imm  
]
[
]
[ ]  
LoaD A with Memory  
LoaD B with Immed.  
X
w
B
AwImXm  
Mem,Imm  
Reg,Imm  
LoaD Memory Immed  
LoaD Register Memory Immed.  
Mem  
w
RegwImImmm  
[
[
[
[
]
]
]
[
[
]
]
[
[
]
g
g
g
g
g
1)  
g
1)  
X
X
LD  
LD  
LD  
A,  
A,  
A,  
A,  
B
X
B
X
EXchange A with Memory  
EXchange A with Memory  
B
X
A
A
A
A
[
Ý
Ý
B , (B  
w
B
g
1)  
]
X , (X  
w
[
[
]
]
[
[
]
]
LoaD A with Memory  
LoaD A with Memory  
B
X
w
w
g
X
XB ,, ((XBwB  
]
w
B
,Imm  
LoaD Memory  
B
Immed.  
B
w
Imm, (Bw 1)  
B
[
]
[
]
]
g
g
1)  
CLR  
INC  
A
A
A
CLeaR A  
INCrement A  
DECrementA  
Load A InDirect from ROM  
Decimal CORrect A  
Rotate A Right thru C  
Rotate A Left thru C  
SWAP nibbles of A  
Set C  
w
Aw0  
AwA  
AwA  
1
1
a
b
DEC  
LAID  
DCOR  
RRC  
RLC  
SWAP  
SC  
A
A
A
A
AwROM (PU,A)  
AxBCD correction of A (follows ADC, SUBC)  
C
CwA7w .. .. .. wAA00wC  
x x x  
C
A7 . . .AA74Ý  
w
wA3 . . . A0  
0
IF C is true, do next instruction  
RC  
IFC  
Reset C  
IF C  
C
Cw01,, HHCCw1  
IFNC  
POP  
PUSH  
IF Not C  
POP the stack into A  
PUSH A onto the stack  
a
[ ]  
SP  
A
A
ISfPCwis not true, do next instruction  
w
SP  
w
A, SP1w, A SP  
b
1
[
]
SP  
[
]
[
]
VL  
VIS  
Vector to Interrupt Service Routine  
Jump absolute Long  
Jump absolute  
Jump relative short  
Jump SubRoutine Long  
Jump SubRoutine  
Jump InDirect  
RETurn from subroutine  
RETurn and SKip  
RETurn from Interrupt  
Generate an Interrupt  
No OPeration  
w
e
JMPL  
JMP  
JP  
JSRL  
JSR  
JID  
RET  
RETSK  
RETI  
INTR  
NOP  
Addr.  
Addr.  
Disp.  
Addr.  
Addr  
PPUCw VU , PL  
w
ii (ii  
PC9 . . . 0wi1(5i bits, 0 to 32k)  
12 bits)  
b
e
r (r is 31 to 32, except 1)  
a
a
PU,SP 2, PC  
PC  
[
[
w
PC  
wPL, SP  
b
b
b
b
]
[
]
]
SP  
SP  
1
1
w
w
wii  
PU,SP 2, PC9 . . . 0  
]
[
w
PL, SP  
w
i
PL  
SP  
SP  
SP  
[
w
ROM (PU,A)  
[
a
b
]
1
]
]
]
]
[
[
[
2, PL  
2, PL  
2, PL  
w
w
SP , PU  
w
w
SP  
a
a
]
b
]
1
[
[
b
SP ,PU  
SP ,PU  
SP  
b
]
w
w
SP 1 ,GIE  
w
1
0FF  
b
PU, SP 2, PC  
[
SP  
w
PL, SP  
1
1
w
w
a
PC  
w
PC  
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30  
Instruction Execution Time  
Most instructions are single byte (with immediate addressing mode instructions taking two bytes).  
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.  
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.  
Arithmetic and Logic Instructions  
Instructions Using A & C  
Transfer of Control  
Instructions  
[
]
B
Direct  
Immed.  
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  
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  
ADD  
ADC  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
3/4  
3/4  
3/4  
3/4  
3/4  
3/4  
3/4  
3/4  
3/4  
2/2  
2/2  
2/2  
2/2  
2/2  
2/2  
2/2  
2/2  
2/2  
SUBC  
AND  
OR  
JSRL  
JSR  
DCOR  
RRCA  
RLCA  
SWAPA  
SC  
JID  
XOR  
IFEQ  
IFNE  
IFGT  
IFBNE  
DRSZ  
VIS  
RET  
RETSK  
RETI  
INTR  
NOP  
RC  
IFC  
IFNC  
PUSHA  
POPA  
ANDSZ  
1/3  
SBIT  
RBIT  
IFBIT  
1/1  
1/1  
1/1  
3/4  
3/4  
3/4  
RPND  
1/1  
Memory Transfer Instructions  
Register  
Indirect  
Register Indirect  
Auto Incr. & Decr.  
Direct Immed.  
a
b
a
b
]
, X  
[
]
[
]
[
]
[
B
X
B
, B  
X
X A,*  
LD A,*  
LD B, Imm  
LD B, Imm  
LD Mem, Imm  
LD Reg, Imm  
IFEQ MD, Imm  
1/1  
1/1  
1/3  
1/3  
2/3  
1/2  
1/2  
1/3  
1/3  
2/3  
2/2  
1/1  
2/2  
k
(IF B 16)  
l
(IF B 15)  
2/2  
3/3  
2/3  
3/3  
2/2  
l
e
*
Memory location addressed by B or X or directly.  
31  
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Opcode Table  
Upper Nibble Along X-Axis  
Lower Nibble Along Y-Axis  
F
E
D
C
B
RRCA  
*
A
9
8
b
JP 15  
b
JP 31  
Ý
Ý
Ý
Ý
Ý
Ý
Ý
Ý
Ý
Ý
Ý
[ ]  
ADC A, B  
LD 0F0,  
LD 0F1,  
LD 0F2,  
LD 0F3,  
LD 0F4,  
LD 0F5,  
LD 0F6,  
LD 0F7,  
LD 0F8,  
LD 0F9,  
i
i
i
i
i
i
i
i
i
i
DRSZ 0F0  
DRSZ 0F1  
DRSZ 0F2  
DRSZ 0F3  
DRSZ 0F4  
DRSZ 0F5  
DRSZ 0F6  
DRSZ 0F7  
DRSZ 0F8  
DRSZ 0F9  
RC  
SC  
ADC A,  
i
0
1
2
3
4
5
6
7
8
9
b
JP 14  
b
JP 30  
Ý
[ ]  
SUB A, B  
SUBC A,  
IFEQ A,  
i
b
JP 13  
b
JP 29  
a
b
a
b
[
[
]
]
[
X A, B  
]
]
Ý
[ ]  
IFEQ A, B  
X A,  
X A,  
VIS  
X
X
i
b
JP 12  
b
JP 28  
[
X A, B  
Ý
[ ]  
IFGT A, B  
IFGT A,  
i
b
JP 11  
b
JP 27  
Ý
[ ]  
ADD A, B  
LAID  
JID  
ADD A,  
AND A,  
XOR A,  
i
b
JP 10  
b
JP 26  
Ý
Ý
i
[ ]  
AND A, B  
RPND  
i
b
b
JP 25  
[
X A, X  
]
[
X A, B  
]
[ ]  
XOR A, B  
JP  
JP  
JP  
JP  
9
8
7
6
i
b
b
b
b
JP 24  
Ý
[
OR A, B  
]
*
*
OR A,  
b
JP 23  
Ý
NOP  
RLCA  
LD A,  
IFNE  
i
IFC  
b
JP 22  
IFNE  
IFEQ  
IFNC  
[
A, B  
]
Ý
Ý
A, i  
Md,  
i
b
b
b
b
b
b
b
JP 21  
a
b
a
b
a
b
Ý
Ý
Ý
Ý
Ý
Ý
[
LD A, X  
]
[
LD A, B  
]
[
] Ý  
, i  
JP  
JP  
JP  
JP  
JP  
JP  
5
4
3
2
1
0
LD 0FA,  
LD 0FB,  
LD 0FC,  
LD 0FD,  
LD 0FE,  
LD 0FF,  
i
DRSZ 0FA  
DRSZ 0FB  
DRSZ 0FC  
DRSZ 0FD  
DRSZ 0FE  
DRSZ 0FF  
LD  
LD  
B
B
INCA  
DECA  
POPA  
RETSK  
RET  
A
B
C
D
E
F
b
JP 20  
[
LD A, X  
]
[
LD A, B  
]
[
] Ý  
, i  
i
i
i
i
i
b
JP 19  
Ý
LD Md,  
DIR  
i
JMPL  
JSRL  
X A,Md  
LD A,Md  
b
JP 18  
b
JP 17  
[
LD A, X  
]
[
LD A, B  
]
[ ] Ý  
LD B , i  
b
JP 16  
Ý
*
*
LD B,  
i
RETI  
http://www.national.com  
32  
Opcode Table (Continued)  
Upper Nibble Along X-Axis  
Lower Nibble Along Y-Axis  
7
6
5
4
3
2
1
0
a
JP 17  
Ý
LD B, 0F  
IFBIT  
]
ANDSZ  
Ý
A, i  
IFBNE 0  
JSR  
x000x0FF  
JMP  
x000x0FF  
INTR  
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
[
0, B  
a
JP 18  
a
Ý
LD B, 0E  
IFBIT  
]
*
IFBNE 1  
IFBNE 2  
IFBNE 3  
IFBNE 4  
IFBNE 5  
IFBNE 6  
IFBNE 7  
IFBNE 8  
IFBNE 9  
IFBNE 0A  
IFBNE 0B  
IFBNE 0C  
IFBNE 0D  
IFBNE 0E  
IFBNE 0F  
JSR  
x100x1FF  
JMP  
x100x1FF  
JP  
2
[
1, B  
a
JP 19  
a
Ý
LD B, 0D  
IFBIT  
]
*
*
JSR  
x200x2FF  
JMP  
x200x2FF  
JP  
3
[
2, B  
a
JP 20  
a
Ý
LD B, 0C  
IFBIT  
]
JSR  
x300x3FF  
JMP  
x300x3FF  
JP  
4
[
3, B  
a
JP 21  
a
Ý
LD B, 0B  
IFBIT  
]
CLRA  
JSR  
x400x4FF  
JMP  
x400x4FF  
JP  
5
[
4, B  
a
JP 22  
a
Ý
LD B, 0A  
IFBIT  
]
SWAPA  
DCORA  
PUSHA  
RBIT  
JSR  
x500x5FF  
JMP  
x500x5FF  
JP  
6
[
5, B  
a
JP 23  
a
Ý
LD B, 09  
IFBIT  
]
JSR  
x600x6FF  
JMP  
x600x6FF  
JP  
7
[
6, B  
a
JP 24  
a
Ý
LD B, 08  
IFBIT  
]
JSR  
x700x7FF  
JMP  
x700x7FF  
JP  
8
[
7, B  
a
JP 25  
a
Ý
LD B, 07  
SBIT  
]
JSR  
x800x8FF  
JMP  
x800x8FF  
JP  
9
[
0, B  
[
0, B  
]
a
JP 26  
a
Ý
LD B, 06  
SBIT  
]
RBIT  
]
JSR  
x900x9FF  
JMP  
x900x9FF  
JP  
10  
11  
12  
13  
14  
15  
16  
[
1, B  
[
1, B  
a
JP 27  
a
Ý
LD B, 05  
SBIT  
]
RBIT  
]
JSR  
xA00xAFF  
JMP  
xA00xAFF  
JP  
[
2, B  
[
2, B  
a
JP 28  
a
Ý
LD B, 04  
SBIT  
]
RBIT  
]
JSR  
xB00xBFF  
JMP  
xB00xBFF  
JP  
[
3, B  
[
3, B  
a
JP 29  
a
Ý
LD B, 03  
SBIT  
]
RBIT  
]
JSR  
xC00xCFF  
JMP  
xC00xCFF  
JP  
[
4, B  
[
4, B  
a
JP 30  
a
Ý
LD B, 02  
SBIT  
]
RBIT  
]
JSR  
xD00xDFF  
JMP  
xD00xDFF  
JP  
[
5, B  
[
5, B  
a
JP 31  
a
Ý
LD B, 01  
SBIT  
]
RBIT  
]
JSR  
xE00xEFF  
JMP  
xE00xEFF  
JP  
[
6, B  
[
6, B  
a
JP 32  
a
Ý
LD B, 00  
SBIT  
]
RBIT  
[ ]  
7, B  
JSR  
xF00xFFF  
JMP  
xF00xFFF  
JP  
[
7, B  
Where,  
i is the immediate data  
Md is a directly addressed memory location  
* is an unused opcode  
Ý
Note: The opcode 60 Hex is also the opcode for IFBIT i,A  
Mask Options  
The mask programmable options are shown below. The op-  
tions are programmed at the same time as the ROM pattern  
submission.  
OPTION 2: HALT  
4 1  
4 2  
Enable HALT mode  
Disable HALT mode  
OPTION 1: CLOCK CONFIGURATION  
OPTION 3: BONDING OPTIONS  
4 1  
Crystal Oscillator (CKI/10)  
4 1  
4 2  
4 3  
4 4  
4 5  
44-Pin PLCC  
40-Pin DIP  
N/A  
G7 (CKO) is clock generator  
output to crystal/resonator  
CKI is the clock input  
28-Pin DIP  
28-Pin SO  
4 2  
Single-pin RC controlled  
oscillator (CKI/10)  
G7 is available as a HALT  
restart and/or general purpose  
input  
33  
http://www.national.com  
Development Support  
SUMMARY  
A full 64k hardware configurable break, trace on, trace  
off control, and pass count increment events.  
#
#
iceMASTERTM: IM-COP8/400ÐFull feature in-circuit em-  
#
Tool set integrated interactive symbolic debuggerÐsup-  
ports both assembler (COFF) and C Compiler (.COD)  
linked object formats.  
ulation for all COP8 products. A full set of COP8 Basic  
and Feature Family device and package specific probes  
are available.  
Real time performance profiling analysis; selectable  
bucket defintion.  
#
#
#
#
COP8 Debug Module: Moderate cost in-circuit emulation  
and development programming unit.  
#
Watch windows, content updated automatically at each  
execution break.  
COP8 Evaluation and Programming Unit: EPU-  
COP888GGÐlow cost in-circuit simulation and develop-  
ment programming unit.  
#
Instruction by instruction memory/register changes dis-  
played on source window when in single step operation.  
Assembler: COP8-DEV-IBMA. A DOS installable cross  
development Assembler, Linker, Librarian and Utility  
Software Development Tool Kit.  
#
Single base unit and debugger software reconfigurable to  
support the entire COP8 family; only the probe personali-  
ty needs to change. Debugger software is processor cus-  
tomized, and reconfigured from a master model file.  
C Compiler: COP8C. A DOS installable cross develop-  
ment Software Tool Kit.  
#
Processor specific symbolic display of registers and bit  
level assignments, configured from master model file.  
#
OTP/EPROM Programmer Support: Covering needs  
from engineering prototype, pilot production to full pro-  
duction environments.  
#
Halt/Idle mode notification.  
#
#
On-Line HELP customized to specific processor using  
master model file.  
IceMASTER (IM) IN-CIRCUIT EMULATION  
The iceMASTER IM-COP8/400 is a full feature, PC based,  
in-circuit emulation tool development and marketed by  
MetaLink Corporation to support the whole COP8 family of  
products. National is a resale vendor for these products.  
Includes a copy of COP8-DEV-IBMA assembler and link-  
er SDK.  
#
IM Order Information  
See Figure 18 for configuration.  
Base Unit  
The iceMASTER IM-COP8/400 with its device specific  
COP8 Probe provides a rich feature set for developing, test-  
ing and maintaining product:  
IM-COP8/400-1  
iceMASTER Base Unit,  
110V Power Supply  
Real-time in-circuit emulation; full 2.4V5.5V operation  
range, full DC-10 MHz clock. Chip options are program-  
mable or jumper selectable.  
#
IM-COP8/400-2  
iceMASTER Base Unit,  
220V Power Supply  
iceMASTER Probe  
Direct connection to application board by package com-  
patible socket or surface assembly.  
#
MHW-884EG28DWPC  
MHW-888EG40DWPC  
MHW-888EG44PWPC  
28 DIP  
40 DIP  
Full 32 kbyte of loadable programming space that over-  
#
44 PLCC  
lays (replaces) the on-chip ROM or EPROM. On-chip  
RAM and I/O blocks are used directly or recreated on  
the probe as necessary.  
Adapter for SO Package  
MHW-SOIC28  
28 SO  
Full 4k frame synchronous trace memory. Address, in-  
#
struction, and 8 unspecified, circuit connectable trace  
lines. Display can be HLL source (e.g., C source), assem-  
bly or mixed.  
TL/DD/976526  
FIGURE 18. COP8 iceMASTER Environment  
http://www.national.com  
34  
Development Support (Continued)  
Debugger software is processor customized, and recon-  
figured from a master model file.  
#
#
iceMASTER DEBUG MODULE (DM)  
The iceMASTER Debug Module is a PC based, combination  
in-circuit emulation tool and COP8 based OTP/EPROM pro-  
gramming tool developed and marketed by MetaLink Corpo-  
ration to support the whole COP8 family of products. Nation-  
al is a resale vendor for these products.  
Processor specific symbolic display of registers and bit  
level assignments, configured from master model file.  
Halt/Idle mode notification.  
#
#
Programming menu supports full product line of program-  
mable OTP and EPROM COP8 products. Program data  
is taken directly from the overlay RAM.  
See Figure 19 for configuration.  
The iceMASTER Debug Module is a moderate cost devel-  
opment tool. It has the capability of in-circuit emulation for a  
specific COP8 microcontroller and in addition serves as a  
programming tool for COP8 OTP and EPROM product fami-  
lies. Summary of features is as follows:  
Programming of 44 PLCC and 68 PLCC parts requires  
external programming adapters.  
#
Includes wallmount power supply.  
#
#
On-board V generator from 5V input or connection to  
PP  
Real-time in-circuit emulation; full operating voltage  
range operation, full DC-10 MHz clock.  
#
external supply supported. Requires V  
PP  
level adjust-  
ment per the family programming specification (correct  
level is provided on an on-screen pop-down display).  
All processor I/O pins can be cabled to an application  
development board with package compatible cable to  
socket and surface mount assembly.  
#
On-line HELP customized to specific processor using  
master model file.  
#
#
Full 32 kbyte of loadable programming space that over-  
#
Includes a copy of COP8-DEV-IBMA assembler and link-  
er SDK.  
DM Order Information  
lays (replaces) the on-chip ROM or EPROM. On-chip  
RAM and I/O blocks are used directly or recreated as  
necessary.  
Debug Module Unit  
100 frames of synchronous trace memory. The display  
#
can be HLL source (C source), assembly or mixed. The  
most recent history prior to a break is available in the  
trace memory.  
COP8-DM/888GG  
Cable Adapters, Kits for COP888  
Configured break points; uses INTR instruction which is  
modestly intrusive.  
#
DM-COP8/28D  
28 DIP  
DM-COP8/40D  
40 DIP  
Software-only supported features are selectable.  
#
#
DM-COP8/44P  
44 PLCC  
Tool set integrated interactive symbolic debuggerÐsup-  
ports both assembler (COFF) and C Compiler (.COD)  
SDK linked object formats.  
Adapter for SO Package  
MHW-SOIC28  
28 SO  
Instruction by instruction memory/register changes dis-  
played when in single step operation.  
#
TL/DD/976527  
FIGURE 19. COP8-DM Environment  
35  
http://www.national.com  
Development Support (Continued)  
Tool set integrated interactive symbolic debuggerÐsup-  
ports both assembler (COFF) and C Compiler (.COD)  
SDK linked object formats.  
#
iceMASTER EVALUATION PROGRAMMING UNIT (EPU)  
The iceMASTER EPU-COP888GG is a PC based, in-circuit  
simulation tool to support the feature family COP8 products.  
Instruction by instruction memory/register changes dis-  
played when in single step operation.  
#
#
#
#
See Figure 20 for configuration.  
The simulation capability is a very low cost means of evalu-  
ating the general COP8 architecture. In addition, the EPU  
has programming capability, with added adapters, for pro-  
gramming the whole COP8 product family of OTP and EP-  
ROM products. The product includes the following features:  
Processor specific symbolic display of registers and bit  
level assignments, configured from master model file.  
Halt/Idle mode notification. Restart requires special han-  
dling.  
Programming menu supports full product line of program-  
mable OTP and EPROM COP8 products. Only a 40 ZIF  
socket is available on the EPU unit. Adapters are avail-  
able for other part package configurations.  
Non-real-time in-circuit simulation. Program overlay  
#
memory is PC resident; instructions are downloaded over  
RS-232 as executed. Approximate performance is  
20 kHz.  
Integral wall mount power supply provides 5V and devel-  
ops the required V to program parts.  
PP  
#
#
Includes a 40-pin DIP cable adapter. Other target pack-  
ages are not supported. All processor I/O pins are ca-  
bled to the application development environment.  
#
Includes a copy of COP8-DEV-IBMA assembler, linker  
SDK.  
EPU Order Information  
Full 32 kbyte of loadable programming space that over-  
#
lays (replaces) the on-chip ROM or EPROM. On-chip  
RAM and I/O blocks are used directly or recreated as  
necessary.  
Evaluation Programming Unit  
EPU-COP888GG  
Evaluation Programming Unit  
with debugger and  
On-chip timer and watch-dog execution are not well syn-  
chronized to the instruction simulation.  
#
programmer control software  
with 40 ZIF programming  
socket.  
100 frames of synchronous trace memory. The display  
#
can be HLL source (e.g., C source), assembly or mixed.  
The most recent history prior to a break is available in the  
trace memory.  
General Programming Adapters  
Up to eight software configured break points; uses INTR  
instruction which is modestly intrusive.  
#
COP8-PGMA-DS  
28 and 20 DIP and SOIC  
adapter.  
Common look-feel debugger software across all Meta-  
Link productsÐonly supported features are selectable.  
#
COP8-PGMA-DS44P  
28 and 20 DIP and SOIC plus  
44 PLCC adapter.  
TL/DD/976528  
FIGURE 20. EPU-COP8 Tool Environment  
http://www.national.com  
36  
Development Support (Continued)  
COP8 ASSEMBLER/LINKER SOFTWARE DEVELOP-  
MENT TOOL KIT  
COP8 C COMPILER  
A C Compiler is developed and marketed by Byte Craft Lim-  
ited. The COP8C compiler is a fully integrated development  
tool specifically designed to support the compact embed-  
ded configuration of the COP8 family of products.  
National Semiconductor offers a relocatable COP8 macro  
cross assembler, linker, librarian and utility software devel-  
opment tool kit. Features are summarized as follows:  
Basic and Feature Family instruction set by ‘‘device’’  
type.  
Features are summarized as follows:  
#
ANSI C with some restrictions and extensions that opti-  
mize development for the COP8 embedded application.  
#
Nested macro capability.  
#
Ý
BITS data type extension. Register declaration pragma  
with direct bit level definitions.  
Extensive set of assembler directives.  
#
#
#
#
#
#
#
Supported on PC/DOS platform.  
C language support for interrupt routines.  
#
#
Generates National standard COFF output files.  
Expert system, rule based code generation and optimiza-  
tion.  
Integrated Linker and Librarian.  
Integrated utilities to generate ROM code file outputs.  
Performs consistency checks against the architectural  
definitions of the target COP8 device.  
#
DUMPCOFF utility.  
This product is integrated as a part of MetaLink tools as a  
development kit, fully supported by the MetaLink debugger.  
It may be ordered separately or it is bundled with the Meta-  
Link products at no additional cost.  
Generates program memory code.  
#
#
Supports linking of compiled object or COP8 assembled  
object formats.  
Order Information  
Global optimization of linked code.  
#
#
Symbolic debug load format fully source level supported  
by the MetaLink debugger.  
Assembler SDK  
COP8-DEV-IBMA  
Assembler SDK on installable  
3.5 PC/DOS Floppy Disk Drive  
format. Periodic upgrades and  
most recent version is available  
on National’s BBS and Internet.  
SINGLE CHIP OTP/EMULATOR SUPPORT  
×
The COP8 family is supported by single chip OTP emula-  
tors. For detailed information refer to the emulator specific  
datasheet and the emulator selection table below:  
Approved List  
Europe  
North  
Manufacturer  
Asia  
America  
a
a
a
a
BP  
Microsystems  
(800) 225-2102  
49-8152-4183  
852-234-16611  
852-2710-8121  
(713) 688-4600  
49-8856-932616  
Fax: (713) 688-0920  
a
Data I/O  
HILO  
(800) 426-1045  
44-0734-440011  
Call  
(206) 881-6444  
North America  
Fax: (206) 882-1043  
a
886-2-764-0215  
(510) 623-8860  
Call Asia  
a
Fax: 886-2-756-6403  
a
Fax: 0-1226-370-434  
ICE  
(800) 624-8949  
(919) 430-7915  
44-1226-767404  
Technology  
a
a
a
MetaLink  
(800) 638-2423  
49-80 9156 96-0  
852-737-1800  
a
Fax: 49-80 9123 86  
(602) 926-0797  
Fax: (602) 693-0681  
a
Systems  
General  
(408) 263-6667  
41-1-9450300  
886-2-917-3005  
a
Fax: 886-2-911-1283  
Needhams  
(916) 924-8037  
Fax: (916) 924-8065  
37  
http://www.national.com  
Development Support (Continued)  
OTP Emulator Ordering Information  
DIAL-A-HELPER via FTP  
ftp nscmicro.nsc.com  
Clock  
Device Number  
Package  
Emulates  
user:  
anonymous  
Option  
@
password: username yourhost.site.domain  
COP87L84EGN-XE Crystal  
COP87L84EGM-XE Crystal  
COP87L88EGN-XE Crystal  
28 DIP  
28 SO  
40 DIP  
COP884CG  
COP884CG  
COP888CG  
DIAL-A-HELPER via a WorldWide Web Browser  
ftp://nscmicro.nsc.com  
National Semiconductor on the WorldWide Web  
COP87L88EGV-XE  
Crystal  
44 PLCC COP888CG  
See us on the WorldWide Web at: http://www.national.com  
CUSTOMER RESPONSE CENTER  
INDUSTRY WIDE OTP/EPROM PROGRAMMING  
SUPPORT  
Complete product information and technical support is avail-  
able from National’s customer response centers.  
Programming support, in addition to the MetaLink develop-  
ment tools, is provided by a full range of independent ap-  
proved vendors to meet the needs from the engineering  
laboratory to full production.  
CANADA/U.S.: Tel:  
email:  
(800) 272-9959  
@
support tevm2.nsc.com  
AVAILABLE LITERATURE  
@
europe.support nsc.com  
EUROPE:  
email:  
For more information, please see the COP8 Basic Family  
User’s Manual, Literature Number 620895, COP8 Feature  
Family User’s Manual, Literature Number 620897 and Na-  
tional’s Family of 8-bit Microcontrollers COP8 Selection  
Guide, Literature Number 630009.  
a
a
a
a
a
Deutsch Tel:  
English Tel:  
Fran3ais Tel:  
Italiano Tel:  
Tel:  
49 (0) 180-530 85 85  
49 (0) 180-532 78 32  
49 (0) 180-532 93 58  
49 (0) 180-534 16 80  
81-043-299-2309  
DIAL-A-HELPER SERVICE  
JAPAN:  
Dial-A-Helper is a service provided by the Microcontroller  
Applications group. The Dial-A-Helper is an Electronic Infor-  
mation System that may be accessed as a Bulletin Board  
System (BBS) via data modem, as an FTP site on the Inter-  
net via standard FTP client application or as an FTP site on  
the Internet using a standard Internet browser such as Net-  
scape or Mosaic.  
a
S.E. ASIA:  
Beijing Tel:  
Shanghai Tel:  
(
(
86) 10-6856-8601  
a
86) 21  
a
Hong Kong Tel: ( 852) 2737-1600  
a
a
a
Korea Tel:  
Malaysia Tel:  
Singapore Tel:  
Taiwan Tel:  
Tel:  
(
(
(
82) 2-3771-6909  
60-4) 644-9061  
65) 255-2226  
The Dial-A-Helper system provides access to an automated  
information storage and retrieval system. The system capa-  
bilities include a MESSAGE SECTION (electronic mail,  
when accessed as a BBS) for communication to and from  
the Microcontroller Applications Group and a FILE SEC-  
TION which consists of several file areas where valuable  
application software and utilities could be found.  
a
886-2-521-3288  
a
AUSTRALIA:  
INDIA:  
(
61) 3-9558-9999  
91) 80-559-9467  
a
(
Tel:  
DIAL-A-HELPER BBS via a Standard Modem  
Modem: CANADA/U.S.: (800) NSC-MICRO  
(800) 672-6427  
a
49) 0-8141-351332  
EUROPE:  
Baud:  
(
14.4k  
Set-up:  
Length: 8-Bit  
Parity:  
None  
Stop Bit: 1  
Operation:  
24 Hours, 7 Days  
http://www.national.com  
38  
39  
http://www.national.com  
Physical Dimensions inches (millimeters) unless otherwise noted  
Molded Dual-In-Line Package (N)  
Order Number COP884CG-XXX/WM  
NS Package Number M28B  
http://www.national.com  
40  
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)  
Molded Dual-In-Line Package (N)  
Order Number COP884CG-XXX/N  
NS Package Number N28B  
Molded Dual-In-Line Package (N)  
Order Number COP888CG-XXX/N  
NS Package Number N40A  
41  
http://www.national.com  
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)  
Plastic Leaded Chip Carrier (V)  
Order Number COP888CG-XXX/V  
NS Package Number V44A  
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 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.  
National Semiconductor  
Corporation  
National Semiconductor  
Europe  
National Semiconductor  
Hong Kong Ltd.  
National Semiconductor  
Japan Ltd.  
a
1111 West Bardin Road  
Arlington, TX 76017  
Tel: 1(800) 272-9959  
Fax: 1(800) 737-7018  
Fax: 49 (0) 180-530 85 86  
13th Floor, Straight Block,  
Ocean Centre, 5 Canton Rd.  
Tsimshatsui, Kowloon  
Hong Kong  
Tel: (852) 2737-1600  
Fax: (852) 2736-9960  
Tel: 81-043-299-2308  
Fax: 81-043-299-2408  
@
Email: europe.support nsc.com  
a
Deutsch Tel: 49 (0) 180-530 85 85  
a
English Tel: 49 (0) 180-532 78 32  
a
Fran3ais Tel: 49 (0) 180-532 93 58  
a
Italiano Tel: 49 (0) 180-534 16 80  
http://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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NSC

COP888CLMHD-1

8-Bit Microcontroller
ETC

COP888CLMHD-3

8-Bit Microcontroller
ETC

COP888CLMHEL-1

8-Bit Microcontroller
ETC