COP888GG-XXX/V [TI]

8-BIT, MROM, 10MHz, MICROCONTROLLER, PQCC44, PLASTIC, LCC-44;
COP888GG-XXX/V
型号: COP888GG-XXX/V
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

8-BIT, MROM, 10MHz, MICROCONTROLLER, PQCC44, PLASTIC, LCC-44

时钟 微控制器 外围集成电路
文件: 总55页 (文件大小:625K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
COP888XG/CS  
COP888xG/CS Family 8-Bit CMOS ROM Based Microcontrollers with 4k to 24k  
Memory, Comparators and USART  
Literature Number: SNOS874  
July 1999  
COP888xG/CS Family  
8-Bit CMOS ROM Based Microcontrollers with 4k to 24k  
Memory, Comparators and USART  
Programmable) versions are available (COP8SGx7 Family).  
Erasable windowed versions are available for use with a  
range of software and hardware development tools.  
General Description  
Note: COP8SG devices are form-fit-function compatible su-  
persets of the COP888xG/CL/CS Family devices, and are  
Family features include an 8-bit memory mapped architec-  
replacements for these in new designs, and design up-  
ture, 10 MHz CKI with 1µs instruction cycle, three multi-  
grades with minimum effort.  
function 16-bit timer/counters, full-duplex USART,  
The COP888xG ROM based microcontrollers are highly inte-  
MICROWIRE/PLUS serial I/O, two Analog comparators,  
grated COP8 Feature core devices with larger memory (4k  
two power saving HALT/IDLE modes, idle timer, MIWU, high  
current outputs, software selectable I/O options, WATCH-  
to 24k) and advanced features including two Analog com-  
parators. These single-chip CMOS devices are suited for  
more complex applications requiring a full featured controller  
with a range of memory sizes, low EMI (except EG), com-  
parators, and a full-duplex USART. Pin and software com-  
patible (different VCC range) 8k toor 32k OTP (One Time  
DOG timer and Clock Monitor, low EMI 2.5V to 5.5V opera-  
tion, and 28/40/44 pin packages.  
Devices included in this datasheet are:  
Memory  
(bytes)  
RAM  
(bytes)  
192  
I/O  
Device  
Packages  
28 DIP/SOIC  
Temperature  
Comments  
4.5V - 5.5V  
Pins  
COP684CS 4k ROM  
COP884CS 4k ROM  
COP984CS 4k ROM  
COP688CS 4k ROM  
COP888CS 4k ROM  
COP988CS 4k ROM  
COP884CG 4k ROM  
COP888CG 4k ROM  
COP684EG 4k ROM  
COP884EG 4k ROM  
COP984EG 4k ROM  
COP688EG 8k ROM  
COP888EG 8k ROM  
24  
-55 to +125˚C  
-40 to +85˚C  
-0 to +70˚C  
192  
24  
28 DIP/SOIC  
192  
24  
28 DIP/SOIC  
2.5V - 4.0V, CSH=4.0V - 6.0V  
4.5V - 5.5V  
192  
36/40  
36/40  
36/40  
24  
40 DIP, 44 PLCC  
40 DIP, 44 PLCC  
40 DIP, 44 PLCC  
28 DIP/SOIC  
-55 to +125˚C  
-40 to +85˚C  
-0 to +70˚C  
192  
192  
2.5V - 4.0V, CSH=4.0V - 6.0V  
2.5V - 6.0V  
128  
-40 to +85˚C  
-40 to +85˚C  
-55 to +125˚C  
-40 to +85˚C  
0 to +70˚C  
128  
34/38  
24  
40 DIP, 44 PLCC  
28 DIP, SOIC  
2.5V - 6.0V  
256  
4.5V - 5.5V  
256  
24  
28 DIP, SOIC  
256  
24  
28 DIP, SOIC  
2.5V - 4.0V, EGH=4.0 - 6.0V  
4.5V - 5.5V  
256  
36/40  
36/40  
40 DIP, 44 PLCC  
-55 to +125˚C  
-40 to +85˚C  
256  
40 DIP, 44  
PLCC/PQFP  
COP988EG 8k ROM  
COP688GG 16k ROM  
256  
512  
36/40  
36/40  
40 DIP, 44 PLCC  
0 to +70˚C  
2.5V - 4.0V, EGH=4.0 - 6.0V  
4.5V - 5.5V  
40 DIP, 44  
-55 to +125˚C  
PLCC/PQFP  
COP888GG 16k ROM  
512  
36/40  
40 DIP, 44  
-40 to +85˚C  
PLCC/PQFP  
COP688HG 20k ROM  
COP888HG 20k ROM  
COP688KG 24k ROM  
COP888KG 24k ROM  
512  
512  
512  
512  
36/40  
36/40  
36/40  
36/40  
40 DIP, 44 PLCC  
40 DIP, 44 PLCC  
40 DIP, 44 PLCC  
40 DIP, 44 PLCC  
-55 to +125˚C  
-40 to +85˚C  
-55 to +125˚C  
-40 to +85˚C  
4.5V - 5.5V  
4.5V - 5.5V  
— External Event counter mode  
— Input Capture mode  
n Quiet design (low radiated emissions)  
n 4 to 24 kbytes on-board ROM  
n 128 to 512 bytes on-board RAM  
Key Features  
n Full duplex USART  
n Three 16-bit timers, each with two 16-bit registers  
supporting:  
— Processor Independent PWM mode  
COP8 , MICROWIRE/PLUS , and WATCHDOG are trademarks of National Semiconductor Corporation.  
TRI-STATE® is a registered trademark of National Semiconductor Corporation.  
iceMASTER® is a registered trademark of MetaLink Corporation.  
© 2000 National Semiconductor Corporation  
DS012829  
www.national.com  
n Up to fourteen multi-source vectored interrupts servicing  
— External Interrupt with selectable edge  
— Idle Timer T0  
— Three Timers (one timer for the CS series)(each with  
2 interrupts)  
— MICROWIRE/PLUS  
— Multi-Input Wake-Up  
— Software Trap  
— USART (2)  
Key Features (Continued)  
Additional Peripheral Features  
n Idle Timer  
n Multi-Input Wake-Up (MIWU) with optional interrupts (8)  
n Two analog comparators (one for the CS series)  
n WATCHDOG and Clock Monitor logic  
n MICROWIRE/PLUS serial I/O  
— Default VIS (default interrupt)  
n 8-bit Stack Pointer SP(stack in RAM)  
n Two 8-bit Register Indirect Data Memory Pointers  
(B and X)  
I/O Features  
n Memory mapped I/O  
n Software selectable I/O options (TRI-STATE® Output,  
Push-Pull Output, Weak Pull-Up Input, High Impedance  
Input)  
n Up to 8 high current outputs  
n Schmitt trigger inputs on ports G and L  
n Packages:  
Fully Static CMOS  
n Two power saving modes: HALT and IDLE  
<
n Low current drain (typically 1 µA)  
n Single supply operation: 2.5V–5.5V (COP88x)  
— 44 PQFP with 40 I/O pins  
— 44 PLCC with 40 I/O pins  
— 40 DIP with 36 I/O pins  
n Temperature ranges:  
0˚C to +70˚C, −40˚C to +85˚C, and −55˚C to +125˚C  
— 28 DIP/SOIC with 24 I/O pins  
Development Support  
n Emulation and OTP devices  
CPU/Instruction Set Features  
n 1 µs instruction cycle time  
n Real time emulation and full program debug offered by  
MetaLink’s Development System  
n Versatile and easy to use instruction set  
Block Diagram  
DS012829-1  
FIGURE 1. COP888xG Block Diagram  
www.national.com  
2
Connection Diagrams  
Dual-In-Line Package  
DS012829-46  
Top View  
Order Number COP884CS-XXX/WM,  
COP984CS-XXX/WM,  
COP984CSH-XXX/WM, COP684CS-XXX/WM,  
COP884CG-XXX/WM,  
DS012829-3  
COP884EG-XXX/WM or  
Top View  
COP884CS-XXX/N, COP984CS-XXX/N,  
COP984CSH-XXX/N, COP884CG-XXX/N,  
COP884EG-XXX/N  
Order Number COP888CS-XXX/N, COP988CS-XXX/N,  
COP688CS-XXX/N,  
COP988CSH-XXX/N, COP888CG-XXX/N,  
COP688EG-XXX/N, COP888GG-XXX/N,  
COP688GG-XXX/N, COP888GG-XXX/N,  
COP688HG-XXX/N, COP888HG-XXX/N,  
COP688KG-XXX/N, or COP888KG-XXX/N  
See NS Package Number N40A  
See NS Package Number M28B or N28A  
Plastic Chip Carrier  
DS012829-2  
Top View  
Order Number COP688CS-XXX/V, COP888CS-XXX/V,  
COP988CS/CSH-XXX/V, COP688EG-XXX/V,  
COP888EG-XXX/V, COP988EG-XXX/V,  
COP888CG-XXX/V,  
DS012829-45  
COP688GG-XXX/V, COP888GG-XXX/V,  
COP688HG-XXX/V, COP888HG-XXX/V,  
COP688KG-XXX/V, or COP888KG-XXX/V  
See NS Package Number V44A  
Top View  
Order Number COP888EG-XXX/VEJ,  
COP688GG-XXX/VEJ, COP888GG-XXX/VEJ,  
See NS Package Number VEJ44A  
FIGURE 2. Connection Diagrams  
3
www.national.com  
Connection Diagrams (Continued)  
Pinouts for 28-, 40- and 44-Pin Packages  
28-Pin  
DIP/SO  
11  
12  
13  
14  
15  
16  
17  
18  
25  
26  
27  
28  
1
40-Pin  
DIP  
17  
18  
19  
20  
21  
22  
23  
24  
35  
36  
37  
38  
3
44-Pin  
PLCC  
17  
18  
19  
20  
25  
26  
27  
28  
39  
40  
41  
42  
3
44-Pin  
PQFP  
11  
12  
13  
14  
19  
20  
21  
22  
33  
34  
35  
36  
41  
42  
43  
44  
23  
24  
25  
26  
7
Port  
L0  
Type  
I/O  
Alt. Fun  
MIWU  
Alt. Fun  
L1  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
WDOUT  
I/O  
I/O  
I/O  
I/O  
I
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
MIWU  
INT  
CKX  
TDX  
RDX  
T2A*  
T2B*  
T3A*  
T3B*  
L2  
L3  
L4  
L5  
L6  
L7  
G0  
G1  
G2  
G3  
G4  
G5  
G6  
G7  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
I0  
T1B  
T1A  
SO  
SK  
2
4
4
SI  
3
5
5
I/CKO  
O
HALT Restart  
4
6
6
19  
20  
21  
22  
25  
26  
27  
28  
29  
30  
31  
32  
9
29  
30  
31  
32  
33  
34  
35  
36  
9
O
O
O
O
O
8
O
9
O
10  
27  
28  
29  
30  
3
I
7
8
I1  
I
COMP1IN−  
COMP1IN+  
COMP1OUT  
COMP2IN−*  
COMP2IN+*  
COMP2OUT*  
10  
11  
12  
13  
14  
15  
16  
39  
40  
1
10  
11  
12  
13  
14  
15  
16  
43  
44  
1
I2  
I
9
I3  
I
10  
I4  
I
I5  
I
4
I6  
I
5
I7  
I
6
C0  
C1  
C2  
C3  
C4  
C5  
C6  
C7  
VCC  
GND  
CKI  
RESET  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
37  
38  
39  
40  
15  
16  
17  
18  
2
2
2
21  
22  
23  
24  
8
6
23  
5
8
33  
7
37  
7
31  
1
24  
34  
38  
32  
*
Note 1: Not available on the CS series  
www.national.com  
4
Absolute Maximum Ratings (Note 4)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Total Current into VCC Pin (Source)  
Total Current out of GND Pin (Sink)  
Storage Temperature Range  
Note 2: Absolute maximum ratings indicate limits beyond which damage to  
the device may occur. DC and AC electrical specifications are not ensured  
when operating the device at absolute maximum ratings.  
100 mA  
110 mA  
−65˚C to +140˚C  
Supply Voltage (VCC  
Voltage at Any Pin  
)
7V  
−0.3V to VCC + 0.3V  
DC Electrical Characteristics 98xEG and 98xCS:  
0˚C TA +70˚C unless otherwise specified  
Parameter  
Operating Voltage  
Conditions  
Min  
Typ  
Max  
Units  
COP98xCS, COP98xEG  
COP98xCSH, COP98xEGH  
Power Supply Ripple (Note 6)  
Supply Current (Note 7)  
CKI = 10 MHz  
2.5  
4.0  
4.0  
6.0  
V
V
V
Peak-to-Peak  
0.1 VCC  
VCC = 6.0V, tc = 1 µs  
VCC = 6.0V, tc = 2.5 µs  
VCC = 4V, tc = 2.5 µs  
VCC = 4V, tc = 10 µs  
VCC = 6.0V, CKI = 0 MHz  
VCC = 4V, CKI = 0 MHz  
12.5  
5.5  
2.5  
1.4  
8
mA  
mA  
mA  
mA  
µA  
CKI = 4 MHz  
CKI = 4 MHz  
CKI = 1 MHz  
<
<
HALT Current (Note 8)  
0.7  
0.3  
4
µA  
IDLE Current  
CKI = 10 MHz  
CKI = 4 MHz  
CKI = 1 MHz  
Input Levels (VIH, VIL)  
RESET  
VCC = 6.0V, tc = 1 µs  
VCC = 6.0V, tc = 2.5 µs  
VCC = 4V, tc = 10 µs  
3.5  
2.5  
0.7  
mA  
mA  
mA  
Logic High  
0.8 VCC  
V
V
Logic Low  
0.2 VCC  
CKI (External adn Crystal Osc.  
Modes)  
Logic High  
0.7 VCC  
0.7 VCC  
V
V
Logic Low  
0.2 VCC  
All Other Inputs  
Logic High  
V
V
Logic Low  
0.2 VCC  
+1  
Hi-Z Input Leakage  
Input Pullup Current  
G and L Port Input Hysteresis  
Output Current Levels  
D Outputs  
VCC = 6.0V, VIN = 0V  
VCC = 6.0V, VIN = 0V  
(Note 10)  
−1  
µA  
µA  
V
−40  
−250  
0.35 VCC  
Source  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 1V  
−0.4  
−0.2  
10  
mA  
mA  
mA  
mA  
Sink  
VCC = 2.5V, VOL = 0.4V  
2.0  
All Others  
Source (Weak Pull-Up Mode)  
VCC = 4V, VOH = 2.7V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 0.4V  
VCC = 2.5V, VOL = 0.4V  
−10  
−2.5  
−0.4  
−0.2  
1.6  
−100  
−33  
µA  
µA  
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
mA  
mA  
mA  
mA  
0.7  
5
www.national.com  
DC Electrical Characteristics 98xEG and 98xCS: (Continued)  
0˚C TA +70˚C unless otherwise specified  
Parameter  
TRI-STATE Leakage  
Allowable Sink/Source  
Current per Pin  
Conditions  
Min  
Typ  
Max  
Units  
VCC = 6.0V  
−1  
+1  
µA  
D Outputs (Sink)  
15  
3
mA  
mA  
All others  
Maximum Input Current  
without Latchup (Notes 9, 10)  
RAM Retention Voltage, Vr  
Input Capacitance  
±
TA = 25˚  
500 ns Rise and Fall Time (min)  
100  
mA  
V
2
7
pF  
pF  
Load Capacitance on D2  
1000  
AC Electrical Characteristics 98xEG and 98xCS:  
0˚C TA +70˚C unless otherwise specified  
Parameter  
Instruction Cycle Time (tc)  
Conditions  
Min  
Typ  
Max  
Units  
Crystal, Resonator  
4V VCC 6.0V  
2.5  
1.0  
7.5  
3.0  
DC  
DC  
DC  
DC  
µs  
µs  
µs  
µs  
<
2.5V VCC 4V  
R/C Oscillator  
4V VCC 6.0V  
<
2.5V VCC 4V  
Inputs  
tSETUP  
4V VCC 6.0V  
200  
500  
60  
ns  
ns  
ns  
ns  
<
2.5V VCC 4V  
tHOLD  
4V VCC 6.0V  
<
2.5V VCC 4V  
150  
Output Propagation Delay  
RL = 2.2k, CL = 100 pF  
tPD1, tPD0  
SO, SK  
4V VCC 6.0V  
0.7  
1.75  
1
µs  
µs  
µs  
µs  
ns  
ns  
ns  
<
2.5V VCC 4V  
All Others  
4V VCC 6.0V  
<
2.5V VCC 4V  
2.5  
MICROWIRE Setup Time (tUWS) (Note 10)  
MICROWIRE Hold Time (tUWH) (Note 10)  
MICROWIRE Output Propagation Delay (tUPD  
Input Pulse Width (Note 11)  
20  
56  
)
220  
Interrupt Input High Time  
1
1
1
1
1
tc  
tc  
Interrupt Input Low Time  
Timer 1, 2, 3 Input High Time  
Timer 1, 2, 3 Input Low Time  
Reset Pulse Width  
tc  
tc  
µs  
www.national.com  
6
Absolute Maximum Ratings (Note 4)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Total Current into VCC Pin (Source)  
Total Current out of GND Pin (Sink)  
Storage Temperature Range  
Note 3: Absolute maximum ratings indicate limits beyond which damage to  
the device may occur. DC and AC electrical specifications are not ensured  
when operating the device at absolute maximum ratings.  
100 mA  
110 mA  
−65˚C to +140˚C  
Supply Voltage (VCC  
Voltage at Any Pin  
)
7V  
−0.3V to VCC + 0.3V  
DC Electrical Characteristics 88xCG, 88xCS, and 88xEG:  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
Operating Voltage  
Conditions  
Min  
Typ  
Max  
Units  
Power Supply Ripple (Note 6)  
Supply Current (Note 7)  
CKI = 10 MHz  
Peak-to-Peak  
0.1 VCC  
V
VCC = 6.0V, tc = 1 µs  
VCC = 6.0V, tc = 2.5 µs  
VCC = 4V, tc = 2.5 µs  
12.5  
5.5  
mA  
mA  
mA  
CKI = 4 MHz  
CKI = 4 MHz  
2.5  
(88xCG & 88xEG only)  
CKI = 1 MHz  
VCC = 4V, tc = 10 µs  
1.4  
mA  
(88xCG & 88xEG only)  
<
<
HALT Current (Note 8)  
(88xCG & 88xEG only)  
IDLE Current  
VCC = 6.0V, CKI = 0 MHz  
VCC = 4V, CKI = 0 MHz  
1.0  
0.5  
8
4
µA  
µA  
CKI = 10 MHz  
VCC = 6.0V, tc = 1 µs  
VCC = 6.0V, tc = 2.5 µs  
VCC = 4V, tc = 10 µs  
3.5  
2.5  
0.7  
mA  
mA  
mA  
CKI = 4 MHz  
CKI = 1 MHz  
(88xCG & 88xEG only)  
Input Levels (VIH, VIL)  
RESET  
Logic High  
0.8 VCC  
V
V
Logic Low  
0.2 VCC  
CKI (External adn Crystal Osc.  
Modes)  
Logic High  
0.7 VCC  
0.7 VCC  
V
V
Logic Low  
0.2 VCC  
All Other Inputs  
Logic High  
V
V
Logic Low  
0.2 VCC  
+2  
Hi-Z Input Leakage  
Input Pullup Current  
G and L Port Input Hysteresis  
Output Current Levels  
D Outputs  
VCC = 6.0V  
−2  
µA  
µA  
V
VCC = 6.0V, VIN = 0V  
(Note 10)  
−40  
−250  
0.35 VCC  
Source  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 1V  
−0.4  
−0.2  
10  
mA  
mA  
mA  
mA  
Sink  
VCC = 2.5V, VOL = 0.4V  
2.0  
All Others  
Source (Weak Pull-Up Mode)  
VCC = 4V, VOH = 2.7V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 0.4V  
−10  
−2.5  
−0.4  
−0.2  
1.6  
−100  
−33  
µA  
µA  
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
mA  
mA  
mA  
7
www.national.com  
DC Electrical Characteristics 88xCG, 88xCS, and 88xEG: (Continued)  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
Conditions  
VCC = 2.5V, VOL = 0.4V  
VCC = 6.0V  
Min  
0.7  
−1  
Typ  
Max  
Units  
mA  
TRI-STATE Leakage  
Allowable Sink/Source  
Current per Pin  
+1  
µA  
D Outputs (Sink)  
15  
3
mA  
mA  
All others  
Maximum Input Current  
without Latchup (Notes 9, 10)  
RAM Retention Voltage, Vr  
Input Capacitance  
±
TA = 25˚  
100  
mA  
V
500 ns Rise and Fall Time (min)  
2
7
pF  
pF  
Load Capacitance on D2  
1000  
AC Electrical Characteristics 888EG, 88xCS, and 88xCG:  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
Instruction Cycle Time (tc)  
Conditions  
Min  
Typ  
Max  
Units  
Crystal, Resonator  
4V VCC 6.0V  
1.0  
2.5  
3.0  
7.5  
DC  
DC  
DC  
DC  
µs  
µs  
µs  
µs  
<
2.5V VCC 4V  
R/C Oscillator  
4V VCC 6.0V  
<
2.5V VCC 4V  
Inputs  
tSETUP  
4V VCC 6.0V  
200  
500  
60  
ns  
ns  
ns  
ns  
<
2.5V VCC 4V  
tHOLD  
4V VCC 6.0V  
<
2.5V VCC 4V  
150  
Output Propagation Delay  
RL = 2.2k, CL = 100 pF  
tPD1, tPD0  
SO, SK  
4V VCC 6.0V  
0.7  
1.75  
1
µs  
µs  
µs  
µs  
ns  
ns  
ns  
<
2.5V VCC 4V  
All Others  
4V VCC 6.0V  
<
2.5V VCC 4V  
2.5  
MICROWIRE Setup Time (tUWS) (Note 10)  
MICROWIRE Hold Time (tUWH) (Note 10)  
MICROWIRE Output Propagation Delay (tUPD  
Input Pulse Width (Note 11)  
20  
56  
)
220  
Interrupt Input High Time  
1
1
1
1
1
tc  
tc  
Interrupt Input Low Time  
Timer 1, 2, 3 Input High Time  
Timer 1, 2, 3 Input Low Time  
Reset Pulse Width  
tc  
tc  
µs  
www.national.com  
8
Absolute Maximum Ratings (Note 4)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Total Current into VCC Pin (Source)  
Total Current out of GND Pin (Sink)  
Storage Temperature Range  
Note 4: Absolute maximum ratings indicate limits beyond which damage to  
the device may occur. DC and AC electrical specifications are not ensured  
when operating the device at absolute maximum ratings.  
100 mA  
110 mA  
−65˚C to +140˚C  
Supply Voltage (VCC  
Voltage at Any Pin  
)
7V  
−0.3V to VCC + 0.3V  
DC Electrical Characteristics 888GG, 888HG, and 888KG:  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
Operating Voltage  
Conditions  
Min  
Typ  
Max  
5.5  
Units  
2.5  
V
V
Power Supply Ripple (Note 6)  
Supply Current (Note 7)  
CKI = 10 MHz  
Peak-to-Peak  
0.1 VCC  
VCC = 5.5V, tc = 1 µs  
VCC = 5.5V, tc = 2.5 µs  
VCC = 4V, tc = 2.5 µs  
VCC = 4V, tc = 10 µs  
VCC = 5.5V, CKI = 0 MHz  
VCC = 4V, CKI = 0 MHz  
12.5  
5.5  
2.5  
1.4  
10  
mA  
mA  
mA  
mA  
µA  
CKI = 4 MHz  
CKI = 4 MHz  
CKI = 1 MHz  
<
HALT Current (Note 8)  
1
<
0.5  
6
µA  
IDLE Current  
CKI = 10 MHz  
CKI = 4 MHz  
VCC = 5.5V, tc = 1 µs  
VCC = 5.5V, tc = 2.5 µs  
VCC = 4V, tc = 10 µs  
3.5  
2.5  
0.7  
mA  
mA  
mA  
CKI = 1 MHz  
Input Levels (VIH, VIL)  
RESET  
Logic High  
0.8 VCC  
0.7 VCC  
V
V
Logic Low  
0.2 VCC  
CKI, All Other Inputs  
Logic High  
V
V
Logic Low  
0.2 VCC  
+2  
Hi-Z Input Leakage  
Input Pullup Current  
G and L Port Input Hysteresis  
Output Current Levels  
D Outputs  
VCC = 5.5V, VIN = 0V  
VCC = 5.5V, VIN = 0V  
(Note 10)  
−2  
µA  
µA  
V
−40  
−250  
0.35 VCC  
Source  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 1V  
−0.4  
−0.2  
10  
mA  
mA  
mA  
mA  
Sink  
VCC = 2.5V, VOL = 0.4V  
2.0  
All Others  
Source (Weak Pull-Up Mode)  
VCC = 4V, VOH = 2.7V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOH = 3.3V  
VCC = 2.5V, VOH = 1.8V  
VCC = 4V, VOL = 0.4V  
VCC = 2.5V, VOL = 0.4V  
VCC = 5.5V  
−10  
−2.5  
−0.4  
−0.2  
1.6  
−100  
−33  
µA  
µA  
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
mA  
mA  
mA  
mA  
µA  
0.7  
TRI-STATE Leakage  
Allowable Sink/Source  
Current per Pin  
−2  
+2  
D Outputs (Sink)  
All others  
15  
3
mA  
mA  
Maximum Input Current  
9
www.national.com  
DC Electrical Characteristics 888GG, 888HG, and 888KG: (Continued)  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
without Latchup (Notes 9, 10)  
RAM Retention Voltage, Vr  
Input Capacitance  
Conditions  
Room Temperature  
Min  
Typ  
Max  
Units  
mA  
V
±
100  
500 ns Rise and Fall Time (min)  
2
7
pF  
Load Capacitance on D2  
(Note 10)  
1000  
pF  
AC Electrical Characteristics 888GG, 888HG, and 888KG:  
−40˚C TA +85˚C unless otherwise specified  
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
(88xCG & 88xEG only)  
Instruction Cycle Time (tc)  
<
Crystal, Resonator  
R/C Oscillator  
2.5V VCC 4V  
1.0  
2.5  
3.0  
7.5  
DC  
DC  
DC  
DC  
µs  
µs  
µs  
µs  
4V VCC 5.5V  
<
2.5V VCC 4V  
4V VCC 5.5V  
Inputs  
tSETUP  
4V VCC 5.5V  
200  
500  
60  
ns  
ns  
ns  
ns  
<
2.5V VCC 4V  
tHOLD  
4V VCC 5.5V  
<
2.5V VCC 4V  
150  
Output Propagation Delay  
RL = 2.2k, CL = 100 pF  
tPD1, tPD0  
SO, SK  
4V VCC 5.5V  
0.7  
1.75  
1
µs  
µs  
µs  
µs  
ns  
ns  
ns  
<
2.5V VCC 4V  
All Others  
4V VCC 5.5V  
<
2.5V VCC 4V  
2.5  
MICROWIRE Setup Time (tUWS) (Note 10)  
MICROWIRE Hold Time (tUWH) (Note 10)  
MICROWIRE Output Propagation Delay (tUPD  
Input Pulse Width (Note 11)  
VCC 4V  
VCC 4V  
VCC 4V  
20  
56  
)
220  
Interrupt Input High Time  
1
1
1
1
1
tc  
tc  
Interrupt Input Low Time  
Timer 1, 2, 3 Input High Time  
Timer 1, 2, 3 Input Low Time  
Reset Pulse Width  
tc  
tc  
µs  
www.national.com  
10  
Absolute Maximum Ratings (Note 5)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Total Current into VCC Pin (Source)  
Total Current out of GND Pin (Sink)  
Storage Temperature Range  
Note 5: Absolute maximum ratings indicate limits beyond which damage to  
the device may occur. DC and AC electrical specifications are not ensured  
when operating the device at absolute maximum ratings.  
100 mA  
110 mA  
−65˚C to +140˚C  
Supply Voltage (VCC  
Voltage at Any Pin  
)
7V  
−0.3V to VCC + 0.3V  
DC Electrical Characteristics 68xCS and 68xxG:  
−55˚C TA +125˚C unless otherwise specified  
Parameter  
Operating Voltage  
Conditions  
Min  
Typ  
Max  
5.5  
Units  
4.5  
V
V
Power Supply Ripple (Note 6)  
Supply Current (Note 7)  
CKI = 10 MHz  
Peak-to-Peak  
0.1 VCC  
VCC = 5.5V, tc = 1 µs  
VCC = 5.5V, tc = 2.5 µs  
VCC = 5.5V, CKI = 0 MHz  
12.5  
5.5  
30  
mA  
mA  
µA  
CKI = 4 MHz  
<
HALT Current (Note 8)  
IDLE Current  
10  
CKI = 10 MHz  
VCC = 5.5V, tc = 1 µs  
VCC = 5.5V, tc = 2.5 µs  
3.5  
2.5  
mA  
mA  
CKI = 4 MHz  
Input Levels (VIH, VIL)  
RESET  
Logic High  
0.8 VCC  
0.7 VCC  
0.7 VCC  
V
V
Logic Low  
0.2 VCC  
0.2 VCC  
CKI (68xCS & 68xEG only)  
Logic High  
V
V
Logic Low  
All Other Inputs  
Logic High  
V
V
Logic Low  
0.2 VCC  
+5  
Hi-Z Input Leakage  
Input Pullup Current  
G and L Port Input Hysteresis  
Output Current Levels  
D Outputs  
VCC = 5.5V, VIN = 0V  
VCC = 5.5V, VIN = 0V  
(Note 10)  
−5  
µA  
µA  
V
−35  
−400  
0.35 VCC  
Source  
VCC = 4.5V, VOH = 3.3V  
VCC = 4.5V, VOL = 1V  
−0.4  
9
mA  
mA  
Sink  
All Others  
Source (Weak Pull-Up Mode)  
Source (Push-Pull Mode)  
Sink (Push-Pull Mode)  
TRI-STATE Leakage  
Allowable Sink/Source  
Current per Pin  
VCC = 4.5V, VOH = 2.7V  
VCC = 4.5V, VOH = 3.3V  
VCC = 4.5V, VOL = 0.4V  
VCC = 5.5V  
−9  
−0.4  
1.4  
−5  
−140  
+5  
µA  
mA  
mA  
µA  
D Outputs (Sink)  
All others  
12  
mA  
mA  
2.5  
Maximum Input Current  
without Latchup (Notes 9, 10)  
RAM Retention Voltage, Vr  
Input Capacitance  
Load Capacitance on D2  
±
Room Temp  
100  
7
mA  
V
500 ns Rise and Fall Time (min)  
(Note 10)  
2
pF  
pF  
(Note 10)  
1000  
11  
www.national.com  
AC Electrical Characteristics 68xCS and 68xxG:  
−55˚C TA +125˚C unless otherwise specified  
Parameter  
Instruction Cycle Time (tc)  
Conditions  
Min  
Typ  
Max  
Units  
Crystal, Resonator  
VCC 4.5V  
1.0  
3.0  
DC  
DC  
µs  
µs  
R/C Oscillator  
VCC 4.5V  
68xCS & 68xEG only)  
Inputs  
tSETUP  
VCC 4.5V  
200  
60  
ns  
ns  
tHOLD  
VCC 4.5V  
Output Propagation Delay  
RL = 2.2k, CL = 100 pF  
tPD1, tPD0  
SO, SK  
VCC 4.5V  
VCC 4.5V  
0.7  
1
µs  
µs  
ns  
ns  
ns  
All Others  
MICROWIRE Setup Time (tUWS) (Note 10)  
MICROWIRE Hold Time (tUWH) (Note 10)  
MICROWIRE Output Propagation Delay (tUPD  
Input Pulse Width (Note 11)  
20  
56  
)
220  
Interrupt Input High Time  
1
1
1
1
1
tc  
tc  
Interrupt Input Low Time  
Timer 1, 2, 3 Input High Time  
Timer 1, 2, 3 Input Low Time  
Reset Pulse Width  
tc  
tc  
µs  
Note 6: Maximum rate of voltage change must be less than 0.5 V/ms.  
Note 7: Supply current is measured after running 2000 cycles with a square wave CKI input, CKO open, inputs at rails and outputs open.  
Note 8: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations. Measurement of IDD HALT is done with device neither sourcing or  
sinking current; with L, C, and G0–G5 programmed as low outputs and not driving a load; all outputs programmed low and not driving a load; all inputs tied to V  
;
CC  
clock monitor and comparators disabled. Parameter refers to HALT mode entered via setting bit 7 of the G Port data register. Part will pull up CKI during HALT in crys-  
tal clock mode.  
Note 9: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages greater than V  
and the pins will have sink current  
CC  
to V when biased at voltages greater than V (the pins do not have source current when biased at a voltage below V ). The effective resistance to V is 750  
CC  
CC  
CC  
CC  
(typical). These two pins will not latch up. The voltage at the pins must be limited to less than 14V. WARNING: Voltages in excess of 14V will cause damage to the  
pins. This warning excludes ESD transients.  
Note 10: Parameter characterized but not tested.  
Note 11: t = Instruction Cycle Time  
c
Comparators AC and DC Characteristics  
VCC = 5V, −40˚C TA +85˚C.  
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
mV  
V
±
±
25  
Input Offset Voltage  
0.4V VIN VCC − 1.5V  
10  
Input Common Mode Voltage Range  
Voltage Gain  
0.4  
VCC − 1.5  
300k  
V/V  
mA  
mA  
µA  
Low Level Output Current  
High Level Output Current  
DC Supply Current per Comparator (When Enabled)  
Response Time  
VOL = 0.4V  
VOH = 4.6V  
1.6  
1.6  
250  
1
100 mV Overdrive,  
100 pF Load  
µs  
www.national.com  
12  
Comparators AC and DC Characteristics (Continued)  
DS012829-4  
FIGURE 3. MICROWIRE/PLUS Timing  
Typical Performance Characteristics (−55˚C TA = +125˚C)  
DS012829-30  
DS012829-31  
DS012829-32  
DS012829-33  
13  
www.national.com  
Typical Performance Characteristics (−55˚C TA = +125˚C) (Continued)  
DS012829-35  
DS012829-34  
DS012829-36  
DS012829-38  
DS012829-37  
DS012829-39  
www.national.com  
14  
Typical Performance Characteristics (−55˚C TA = +125˚C) (Continued)  
DS012829-40  
DS012829-41  
L2 MIWU or TDX  
Pin Descriptions  
L1 MIWU or CKX  
VCC and GND are the power supply pins. All VCC and GND  
L0 MIWU  
pins must be connected.  
Port G is an 8-bit port with 5 I/O pins (G0, G2–G5), an input  
pin (G6), and a dedicated output pin (G1). Pins G0 and  
G2–G6 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 oscillator  
mask option selected. With the crystal oscillator option se-  
lected, 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, G2–G5) can be indi-  
vidually configured under software control.  
CKI is the clock input. This can come from an R/C generated  
oscillator, or a crystal oscillator (in conjunction with CKO).  
See Oscillator Description section.  
RESET is the master reset input. See Reset Description sec-  
tion.  
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 re-  
served for the input pins of each I/O port. (See the memory  
map for the various addresses associated with the I/O ports.)  
Figure 4 shows the I/O port configurations. The DATA and  
CONFIGURATION registers allow for each port bit to be in-  
dividually configured under software control as shown below:  
Since G6 is an input only pin and G7 is the dedicated CKO  
clock output pin (crystal clock option) or general purpose in-  
put (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 on the next page. Reading the  
G6 and G7 data bits will return zeros.  
CONFIGURATION  
DATA  
Register  
0
Port Set-Up  
Register  
0
Hi-Z Input  
(TRI-STATE Output)  
Input with Weak Pull-Up  
Push-Pull Zero Output  
Push-Pull One Output  
0
1
1
1
0
1
PORT L is an 8-bit I/O port. All L-pins have Schmitt triggers  
on the inputs.  
The Port L supports Multi-Input Wake Up on all eight pins. L1  
is used for the USART external clock. L2 and L3 are used for  
the USART 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 (execpt on the CS se-  
ries).  
DS012829-5  
FIGURE 4. I/O Port Configurations  
The Port L has the following alternate features:  
L7 MIWU or T3B  
Note that the chip will be placed in the HALT mode by writing  
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.  
L6 MIWU or T3A  
L5 MIWU or T2B  
L4 MIWU or T2A  
Writing a “1” to bit 6 of the Port G Configuration Register en-  
ables the MICROWIRE/PLUS to operate with the alternate  
L3 MIWU or RDX  
15  
www.national.com  
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.  
Pin Descriptions (Continued)  
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.  
S is the 8-bit Data Segment Address Register used to extend  
the lower half of the address range (00 to 7F) into 256 data  
segments of 128 bytes each.  
Config Reg.  
CLKDLY  
Alternate SK  
Data Reg.  
HALT  
IDLE  
All the CPU registers are memory mapped with the excep-  
tion of the Accumulator (A) and the Program Counter (PC).  
G7  
G6  
PROGRAM MEMORY  
Port G has the following alternate features:  
G6 SI (MICROWIRE Serial Data Input)  
G5 SK (MICROWIRE Serial Clock)  
G4 SO (MICROWIRE Serial Data Output)  
G3 T1A (Timer T1 I/O)  
The program memory consists of up to 24 kbytes 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.  
G2 T1B (Timer T1 Capture Input)  
G0 INTR (External Interrupt Input)  
Port G has the following dedicated functions:  
DATA MEMORY  
G7 CKO Oscillator dedicated output or general purpose  
input  
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 associated  
with the timers (with the exception of the IDLE timer). Data  
memory is addressed directly by the instruction or indirectly  
by the B, X, SP pointers and S register.  
G1 WDOUT WATCHDOG and/or Clock Monitor dedi-  
cated output  
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.  
The data memory consists of up to 512 bytes of RAM. Six-  
teen bytes of RAM are mapped as “registers” at addresses  
0F0 to 0FF Hex. These registers can be loaded immediately,  
and also decremented and tested with the DRSZ (decrement  
register and skip if zero) instruction. The memory pointer  
registers X, SP, B and S are memory mapped into this space  
at address locations 0FC to 0FF Hex respectively, with the  
other registers being available for general usage.  
Port I is an eight-bit Hi-Z input port.  
Port I1–I3 are used for Comparator 1. Port I4–I6 are used for  
Comparator 2.  
The Port I has the following alternate features:  
I6 COMP2OUT (Comparator 2 Output)  
I5 COMP2+IN (Comparator 2 Positive Input)  
I4 COMP2−IN (Comparator 2 Negative Input)  
I3 COMP1OUT (Comparator 1 Output)  
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 accumula-  
tor (A) bits can also be directly and individually tested.  
Note: RAM contents are undefined upon power-up.  
I2 COMP1+IN (Comparator 1 Positive Input)  
I1 COMP1−IN (Comparator 1 Negative Input)  
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 outputs (ex-  
cept D2) together in order to get a higher drive.  
Data Memory Segment RAM  
Extension  
Data memory address 0FF is used as a memory mapped lo-  
cation for the Data Segment Address Register (S).  
Functional Description  
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  
memory (RAM). Both ROM and RAM have their own sepa-  
rate addressing space with separate address buses. The ar-  
chitecture, though based on Harvard architecture, permits  
transfer of data from ROM to RAM.  
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 previously.  
With the exception of the RAM register memory from ad-  
dress locations 00F0 to 00FF, all RAM memory is memory  
mapped with the upper bit of the single-byte address being  
equal to zero. This allows the upper bit of the single-byte ad-  
dress 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,  
CPU REGISTERS  
The CPU can do an 8-bit addition, subtraction, logical or shift  
operation in one instruction (tc) cycle time.  
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)  
B is an 8-bit RAM address pointer, which can be optionally  
post auto incremented or decremented.  
X is an 8-bit alternate RAM address pointer, which can be  
optionally post auto incremented or decremented.  
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16  
Data Memory Segment RAM  
Extension (Continued)  
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.  
Figure 5 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.  
The instructions that utilize the stack pointer (SP) always ref-  
erence the stack as part of the base segment (Segment 0),  
regardless of the contents of the S register. The S register is  
not changed by these instructions. Consequently, the stack  
(used with subroutine linkage and interrupts) is always lo-  
cated in the base segment. The stack pointer will be intitial-  
ized to point at data memory location 006F as a result of re-  
set.  
DS012829-6  
*
Reads as all ones.  
FIGURE 5. RAM Organization  
Reset  
The 128 bytes of RAM contained in the base segment are  
split between the lower and upper base segments. The first  
112 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.  
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 dedi-  
cated 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  
USART registers PSR, ENU (except that TBMT bit is set),  
ENUR and ENUI are cleared. The Comparator Select Regis-  
ter is cleared. The S register is initialized to zero. The  
Multi-Input Wakeup registers WKEN and WKEDG are  
cleared. Wakeup register WKPND is unknown. The stack  
pointer, SP, is initialized to 6F hex.  
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 bytes of RAM are  
memory mapped from segment 1 up through segment 3 (see  
Figure 5).  
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 tC clock cycles. The Clock Monitor bit  
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 tC–32 tC clock cycles following  
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 6 should be used  
to ensure that the RESET pin is held low until the power sup-  
ply to the chip stabilizes.  
17  
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Reset (Continued)  
R1  
R2  
C1  
C2  
(pF)  
CKI Freq Conditions  
(MHz)  
(k) (M) (pF)  
0
0
1
1
30  
30–36  
4
VCC = 5V  
200 100–150  
0.455  
VCC = 2.5V  
TABLE 2. RC Oscillator Configuration, TA = 25˚C  
R
C
CKI Freq  
(MHz)  
Instr. Cycle Conditions  
(µs)  
(k) (pF)  
DS012829-7  
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  
VCC = 5V  
VCC = 5V  
VCC = 5V  
>
RC 5 x Power Supply Rise Time  
100  
100  
FIGURE 6. Recommended Reset Circuit  
Note: 3k R 200k  
50 pF C 200 pF  
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  
cycle clock (1/tc).  
CONTROL REGISTERS  
CNTRL Register (Address X'00EE)  
T1C3 T1C2 T1C1 T1C0 MSEL IEDG  
Bit 7  
SL1  
SL0  
Figure 7 shows the Crystal and R/C oscillator diagrams.  
Bit 0  
CRYSTAL OSCILLATOR  
The Timer1 (T1) and MICROWIRE/PLUS control register  
contains the following bits:  
CKI and CKO can be connected to make a closed loop crys-  
tal (or resonator) controlled oscillator.  
T1C3  
T1C2  
T1C1  
T1C0  
Timer T1 mode control bit  
Timer T1 mode control bit  
Timer T1 mode control bit  
Timer T1 Start/Stop control in timer  
Table 1 shows the component values required for various  
standard crystal values.  
R/C OSCILLATOR  
modes 1 and 2, T1 Underflow Interrupt  
Pending Flag in timer mode 3  
By selecting CKI as a single pin oscillator input, a single pin  
R/C oscillator circuit can be connected to it. CKO is available  
as a general purpose input, and/or HALT restart input.  
MSEL  
IEDG  
Selects G5 and G4 as MICROWIRE/PLUS  
signals SK and SO respectively  
Table 2 shows the variation in the oscillator frequencies as  
functions of the component (R and C) values.  
External interrupt edge polarity select  
(0 = Rising edge, 1 = Falling edge)  
SL1 & SL0 Select the MICROWIRE/PLUS clock divide  
by (00 = 2, 01 = 4, 1x = 8)  
PSW Register (Address X'00EF)  
HC  
C
T1PNDA T1ENA EXPND BUSY EXEN GIE  
Bit 0  
Bit 7  
The PSW register contains the following select bits:  
HC  
C
Half Carry Flag  
Carry Flag  
DS012829-8  
T1PNDA Timer T1 Interrupt Pending Flag (Autoreload  
RA in mode 1, T1 Underflow in Mode 2, T1A  
capture edge in mode 3)  
T1ENA  
Timer T1 Interrupt Enable for Timer Underflow  
or T1A Input capture edge  
EXPND External interrupt pending  
BUSY  
EXEN  
GIE  
MICROWIRE/PLUS busy shifting flag  
DS012829-9  
Enable external interrupt  
FIGURE 7. Crystal and R/C Oscillator Diagrams  
Global interrupt enable (enables interrupts)  
The Half-Carry flag is also affected by all the instructions that  
affect the Carry flag. The SC (Set Carry) and R/C (Reset  
Carry) instructions will respectively set or clear both the carry  
flags. In addition to the SC and R/C instructions, ADC,  
SUBC, RRC and RLC instructions affect the Carry and Half  
Carry flags.  
TABLE 1. Crystal Oscillator Configuration, TA = 25˚C  
R1  
(k) (M) (pF)  
30  
R2  
C1  
C2  
(pF)  
CKI Freq Conditions  
(MHz)  
0
1
30–36  
10  
VCC = 5V  
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18  
CONTROL REGISTERS (Continued)  
Timers  
These devices contain a very versatile set of timers (T0, T1,  
T2, T3 for all except the CS series, which only use T0 and  
T1). All timers and associated autoreload/capture registers  
power up containing random data.  
ICNTRL Register (Address X'00E8)  
Reserved  
Bit 7  
LPEN  
T0PND  
T0EN µWPND µWEN T1PNDB  
T1ENB  
Bit 0  
The ICNTRL register contains the following bits:  
Reserved This bit is reserved and should be zero  
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 rate  
of the instruction cycle clock, tc. The user cannot read or  
write to the IDLE Timer T0, which is a count down timer.  
LPEN  
L Port Interrupt Enable (Multi-Input Wakeup/  
Interrupt)  
T0PND  
T0EN  
Timer T0 Interrupt pending  
Timer T0 Interrupt Enable (Bit 12 toggle)  
MICROWIRE/PLUS interrupt pending  
Enable MICROWIRE/PLUS interrupt  
µWPND  
µWEN  
The Timer T0 supports the following functions:  
j
j
j
Exit out of the Idle Mode (See Idle Mode description)  
WATCHDOG logic (See WATCHDOG description)  
Start up delay out of the HALT mode  
T1PNDB Timer T1 Interrupt Pending Flag for T1B cap-  
ture edge  
T1ENB  
Timer T1 Interrupt Enable for T1B Input cap-  
ture 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  
clock frequency (tc = 1 µs). A control flag T0EN allows the in-  
terrupt 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.  
T2CNTRL Register (Address X'00C6)  
T2C3  
Bit 7  
T2C2  
T2C1  
T2C0  
T2PNDA  
T2ENA  
T2PNDB  
T2ENB  
Bit 0  
The T2CNTRL control register contains the following bits:  
T2C3  
T2C2  
T2C1  
T2C0  
Timer T2 mode control bit  
Timer T2 mode control bit  
Timer T2 mode control bit  
TIMER T1, TIMER T2 AND TIMER T3  
These devices can have a set of up to three powerful timer/  
counter blocks, T1, T2 and T3. The associated features and  
functioning 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.  
Timer T2 Start/Stop control in timer  
modes 1 and 2, T2 Underflow Interrupt Pend-  
ing Flag in timer mode 3  
T2PNDA Timer T2 Interrupt Pending Flag (Autoreload  
RA in mode 1, T2 Underflow in mode 2, T2A  
capture edge in mode 3)  
Each timer block consists of a 16-bit timer, Tx, and two sup-  
porting 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 Independent  
PWM mode, External Event Counter mode, and Input Cap-  
ture mode.  
T2ENA  
Timer T2 Interrupt Enable for Timer Underflow  
or T2A Input capture edge  
T2PNDB Timer T2 Interrupt Pending Flag for T2B cap-  
ture edge  
T2ENB  
Timer T2 Interrupt Enable for Timer Underflow  
or T2B Input capture edge  
Note: The T2CNTRL register is not available on the CS series.  
T3CNTRL Register (Address X'00B6)  
The control bits TxC3, TxC2, and TxC1 allow selection of the  
different modes of operation.  
T3C3  
Bit 7  
T3C2  
T3C1  
T3C0  
T3PNDA  
T3ENA  
T3PNDB  
T3ENB  
Bit 0  
Mode 1. Processor Independent PWM Mode  
The T3CNTRL control register contains the following bits:  
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.  
T3C3  
T3C2  
T3C1  
T3C0  
Timer T3 mode control bit  
Timer T3 mode control bit  
Timer T3 mode control bit  
Timer T3 Start/Stop control in timer  
modes 1 and 2, T3 Underflow Interrupt Pend-  
ing Flag in timer mode 3  
T3PNDA Timer T3 Interrupt Pending Flag (Autoreload  
RA in mode 1, T3 Underflow in mode 2, T3A  
capture edge in mode 3)  
In this mode the timer Tx counts down at a fixed rate of tc.  
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.  
T3ENA  
Timer T3 Interrupt Enable for Timer Underflow  
or T3A Input capture edge  
T3PNDB Timer T3 Interrupt Pending Flag for T3B cap-  
ture edge  
T3ENB  
Timer T3 Interrupt Enable for Timer Underflow  
or T3B Input capture edge  
The Tx Timer control bits, TxC3, TxC2 and TxC1 set up the  
timer for PWM mode operation.  
Note: The T3CNTRL regoster os mpt avao;ab;e pm tje CS series.  
Figure 8 shows a block diagram of the timer in PWM mode.  
19  
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Timers (Continued)  
The underflows can be programmed to toggle the TxA output  
pin. The underflows can also be programmed to generate in-  
terrupts.  
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 timer.  
Setting the timer enable flag TxENB will cause an interrupt  
when a timer underflow causes the RxB register to be re-  
loaded into the timer. Resetting the timer enable flags will  
disable the associated interrupts.  
DS012829-11  
FIGURE 9. Timer in External Event Counter 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.  
Mode 3. Input Capture Mode  
The device can precisely measure external frequencies or  
time external events by placing the timer block, Tx, in the in-  
put capture mode.  
In this mode, the timer Tx is constantly running at the fixed tc  
rate. The two registers, RxA and RxB, act as capture regis-  
ters. 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.  
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 Tx-  
ENA allows the interrupt on TxA to be either enabled or dis-  
abled. Setting the TxENA flag enables interrupts to be gener-  
ated when the selected trigger condition occurs on the TxA  
pin. Similarly, the flag TxENB controls the interrupts from the  
TxB pin.  
DS012829-10  
FIGURE 8. Timer in PWM Mode  
Mode 2. External Event Counter Mode  
This mode is quite similar to the processor independent  
PWM mode described above. The main difference is that the  
timer, 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 TxP-  
NDA pending flag. Setting the TxENA control flag will cause  
an interrupt when the timer underflows.  
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.  
In this mode the input pin TxB can be used as an indepen-  
dent positive edge sensitive interrupt input if the TxENB con-  
trol flag is set. The occurrence of a positive edge on the TxB  
input pin is latched into the TxPNDB flag.  
Figure 9 shows a block diagram of the timer in External  
Event Counter mode.  
Figure 10 shows a block diagram of the timer in Input Cap-  
ture mode.  
Note: The PWM output is not available in this mode since the TxA pin is being  
used as the counter input clock.  
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20  
Timers (Continued)  
DS012829-12  
FIGURE 10. Timer in Input Capture Mode  
TIMER CONTROL FLAGS  
The control bits and their functions are summarized below.  
TxC3  
TxC2  
TxC1  
TxC0  
Timer mode control  
Timer mode control  
Timer mode control  
Timer Start/Stop control in Modes 1 and 2 (Pro-  
cessor Independent PWM and External Event  
Counter), where 1 = Start, 0 = Stop  
Timer Underflow Interrupt Pending Flag in  
Mode 3 (Input Capture)  
TxPNDA Timer Interrupt Pending Flag  
TxENA  
Timer Interrupt Enable Flag  
1 = Timer Interrupt Enabled  
0 = Timer Interrupt Disabled  
TxPNDB Timer Interrupt Pending Flag  
TxENB  
Timer Interrupt Enable Flag  
1 = Timer Interrupt Enabled  
0 = Timer Interrupt Disabled  
21  
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Timers (Continued)  
The timer mode control bits (TxC3, TxC2 and TxC1) are detailed below:  
Interrupt A  
Source  
Interrupt B  
Source  
Timer  
Mode  
TxC3  
TxC2  
TxC1  
Description  
Counts On  
1
1
0
0
1
0
PWM: TxA Toggle  
Autoreload RA  
Autoreload RA  
Autoreload RB  
Autoreload RB  
tC  
1
PWM: No TxA  
Toggle  
tC  
0
0
0
0
0
1
0
1
0
External Event  
Counter  
Timer  
Underflow  
Pos. TxB Edge  
Pos. TxB Edge  
Pos. TxB Edge  
Pos. TxA  
Edge  
2
External Event  
Counter  
Timer  
Underflow  
Pos. TxA  
Edge  
Captures:  
Pos. TxA Edge  
or Timer  
tC  
tC  
tC  
tC  
TxA Pos. Edge  
TxB Pos. Edge  
Captures:  
Underflow  
1
0
1
1
1
1
0
1
1
Pos. TxA  
Neg. TxB  
Edge  
TxA Pos. Edge  
TxB Neg. Edge  
Captures:  
Edge or Timer  
Underflow  
3
Neg. TxA  
Neg. TxB  
Edge  
TxA Neg. Edge  
TxB Neg. Edge  
Captures:  
Edge or Timer  
Underflow  
Neg. TxA  
Neg. TxB  
Edge  
TxA Neg. Edge  
TxB Neg. Edge  
Edge or Timer  
Underflow  
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 cir-  
cuitry is enabled. The IDLE timer is loaded with a value of  
256 and is clocked with the tc instruction cycle clock. The tc  
clock is derived by dividing the oscillator clock down by a fac-  
tor 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.  
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 and timer T0 are active but all other microcon-  
troller activities are stopped. In either mode, all on-board  
RAM, registers, I/O states, and timers (with the exception of  
T0) are unaltered.  
HALT MODE  
The device can be placed in the HALT mode by writing a “1”  
to the HALT flag (G7 data bit). All microcontroller activities,  
including the clock and timers, are stopped. The WATCH-  
DOG logic on the device is disabled during the HALT mode.  
However, the clock monitor circuitry if enabled remains ac-  
tive 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 dis-  
abled after the device comes out of reset (resetting the Clock  
Monitor control bit with the first write to the WDSVR register).  
In the HALT mode, the power requirements of the device are  
minimal and the applied voltage (VCC) may be decreased to  
Vr (Vr = 2.0V) without altering the state of the machine.  
If an RC clock option is being used, the fixed delay is intro-  
duced optionally. A control bit, CLKDLY, mapped as configu-  
ration bit G7, controls whether the delay is to be introduced  
or not. The delay is included if CLKDLY is set, and excluded  
if CLKDLY is reset. The CLKDLY bit is cleared on reset.  
The device has two mask options associated with the HALT  
mode. The first mask option enables the HALT mode feature,  
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,  
the HALT flag will remain “0”).  
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 second  
method is with a low to high transition on the CKO (G7) pin.  
This method precludes the use of the crystal clock configura-  
tion (since CKO becomes a dedicated output), and so may  
only be used with an RC clock configuration. The third  
method of exiting the HALT mode is by pulling the RESET  
pin low.  
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 and the IDLE Timer  
T0, are stopped. The power supply requirements of the  
Since a crystal or ceramic resonator may be selected as the  
oscillator, the Wakeup signal is not allowed to start the chip  
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22  
device will first execute the Timer T0 interrupt service routine  
and then return to the instruction following the “Enter Idle  
Mode” instruction.  
Power Save Modes (Continued)  
micro-controller in this mode of operation are typically  
around 30% of normal power requirement of the microcon-  
troller.  
Alternatively, the user can enter the IDLE mode with the  
IDLE Timer T0 interrupt disabled. In this case, the device will  
resume normal operation with the instruction immediately  
following the “Enter IDLE Mode” instruction.  
Note: It is necessary to program two NOP instructions following both the set  
HALT mode and set IDLE mode instructions. These NOP instructions  
are necessary to allow clock resynchronization following the HALT or  
IDLE modes.  
As with the HALT mode, the device can be returned to 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 (repre-  
senting 4.096 ms at internal clock frequency of 10 MHz, tc =  
1 µs) of the IDLE Timer toggles.  
This toggle condition of the thirteenth bit of the IDLE Timer  
T0 is latched into the T0PND pending flag.  
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.  
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.  
Figure 11 shows the Multi-Input Wakeup logic.  
The user can enter the IDLE mode with the Timer T0 inter-  
rupt enabled. In this case, when the T0PND bit gets set, the  
DS012829-13  
FIGURE 11. Multi-Input Wake Up Logic  
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 Register WKEN. The Reg-  
ister WKEN is an 8-bit read/write register, which contains a  
control bit for every L port bit. Setting a particular WKEN bit  
enables a Wakeup from the associated L port pin.  
an edge select entails several steps in order to avoid a  
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 be-  
ing re-enabled.  
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 program  
would be as follows:  
The user can select whether the trigger condition on the se-  
lected 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 Register 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  
RBIT 5, WKEN  
; Disable MIWU  
SBIT 5, WKEDG ; Change edge polarity  
RBIT 5, WKPND ; Reset pending flag  
SBIT 5, WKEN  
; Enable MIWU  
23  
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The Wakeup signal will not start the chip running immedi-  
ately since crystal oscillators or ceramic resonators have a fi-  
nite start up time. The IDLE Timer (T0) generates a fixed de-  
lay to ensure that the oscillator has indeed stabilized before  
allowing the device to execute instructions. In this case,  
upon detecting a valid Wakeup signal, only the oscillator cir-  
cuitry and the IDLE Timer T0 are enabled. The IDLE Timer is  
Multi-Input Wakeup (Continued)  
If the L port bits have been used as outputs and then  
changed to inputs with Multi-Input Wakeup/Interrupt, a safety  
procedure should also be followed to avoid wakeup condi-  
tions. After the selected L port bits have been changed from  
output to input but before the associated WKEN bits are en-  
abled, the associated edge select bits in WKEDG should be  
set or reset for the desired edge selects, followed by the as-  
sociated WKPND bits being cleared.  
loaded with a value of 256 and is clocked from the t  
c instruc-  
tion cycle clock. The tc clock is derived by dividing down the  
oscillator clock by a factor of 10. A Schmitt trigger following  
the CKI on-inverter ensures that the IDLE timer is clocked  
only when the oscillator has a sufficiently large amplitude to  
meet the Schmitt trigger specifications. This Schmitt trigger  
is not part of the oscillator closed loop. The start-up time-out  
from the IDLE timer enables the clock signals to be routed to  
the rest of the chip.  
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-Input 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 cor-  
responding 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 must  
clear the pending flags before attempting 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 configuration  
bit allows the clock start up delay to be optionally inserted.  
Setting CLKDLY flag high will cause clock start up delay to  
be inserted and resetting it will exclude the clock start up de-  
lay. The CLKDLY flag high will cause 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 op-  
tions.  
WKEN, WKPND and WKEDG are all read/write registers,  
and are cleared at reset.  
USART  
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 device contains a full-duplex software programmable  
USART. The USART (Figure 12) consists of a transmit shift  
register, a receive shift register and seven addressable reg-  
isters, as follows: a transmit buffer register (TBUF), a re-  
ceiver buffer register (RBUF), a USART control and status  
register (ENU), a USART receive control and status register  
(ENUR), a USART interrupt and clock source register  
(ENUI), a prescaler select register (PSR) and baud (BAUD)  
register. The ENU register contains flags for transmit and re-  
ceive 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 framing, data overrun and parity errors while the US-  
ART is receiving.  
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 speci-  
fies the trigger condition to be either a positive or a negative  
edge. Finally, the register WKPND latches in the pending  
trigger conditions.  
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.  
Other functions of the ENUR register include saving the  
ninth bit received in the data frame, enabling or disabling the  
USART’s attention mode of operation and providing addi-  
tional 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 selecting the  
number of stop bits and enabling or disabling transmit and  
receive interrupts. A control flag in this register can also se-  
lect the USART mode of operation: asynchronous or  
synchronous.  
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 ex-  
ecution 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 in-  
terrupt service routine and then revert to normal operation.  
(See HALT MODE for clock option wakeup information.)  
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24  
USART (Continued)  
DS012829-14  
FIGURE 12. USART Block Diagram  
USART CONTROL AND STATUS REGISTERS  
PEN = 1  
Parity enabled.  
The operation of the USART is programmed through three  
registers: ENU, ENUR and ENUI.  
PSEL1, PSEL0: Parity select bits. Read/Write, cleared on  
reset.  
PSEL1 = 0, PSEL0 = 0  
PSEL1 = 0, PSEL0 = 1  
PSEL1 = 1, PSEL0 = 0  
PSEL1 = 1, PSEL0 = 1  
Odd Parity (if Parity enabled)  
Even Parity (if Parity enabled)  
Mark(1) (if Parity enabled)  
Space(0) (if Parity enabled)  
DESCRIPTION OF USART REGISTER BITS  
ENU-USART Control and Status Register (Address at 0BA)  
PEN PSEL1 XBIT9/ CHL1  
CHL0  
ERR  
RBFL TBMT  
PSEL0  
XBIT9/PSEL0: Programs the ninth bit for transmission when  
the USART is operating with nine data bits per frame. For  
seven or eight data bits per frame, this bit in conjunction with  
PSEL1 selects parity. Read/Write, cleared on reset.  
Bit 7  
Bit 0  
PEN: This bit enables/disables Parity (7- and 8-bit modes  
only). Read/Write, cleared on reset.  
PEN = 0  
Parity disabled.  
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RCVG: This bit is set high whenever a framing error occurs  
and goes low when RDX goes high. Read only, cleared on  
reset.  
USART (Continued)  
CHL1, CHL0: These bits select the character frame format.  
Parity is not included and is generated/verified by hardware.  
Read/Write, cleared on reset.  
ENUI-USART Interrupt and Clock Source Register  
(Address at 0BC)  
CHL1 = 0, CHL0 = 0  
CHL1 = 0, CHL0 = 1  
The frame contains eight data bits.  
STP2 STP78 ETDX SSEL XRCLK XTCLK  
Bit 7  
ERI  
ETI  
The frame contains seven data  
bits.  
Bit 0  
STP2: This bit programs the number of Stop bits to be trans-  
mitted. Read/Write, cleared on reset.  
CHL1 = 1, CHL0 = 0  
CHL1 = 1, CHL0 = 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.  
STP2 = 0  
STP2 = 1  
One Stop bit transmitted.  
Two Stop bits transmitted.  
STP78: This bit is set to program the last Stop bit to be 7/8th  
ERR: This bit is a global USART error flag which gets set if  
any or a combination of the errors (DOE, FE, PE) occur.  
Read only; it cannot be written by software, cleared on reset.  
of a bit in length. Read/Write, cleared on reset.  
ETDX: TDX (USART 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. Read/Write, cleared on re-  
set.  
RBFL: This bit is set when the USART 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. Read only; it cannot be written by software, cleared  
on reset.  
SSEL: USART mode select. Read/Write, cleared on reset.  
TBMT: This bit is set when the USART 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. Read only, bit is set to “one” on reset; it  
cannot be written by software.  
SSEL = 0  
SSEL = 1  
Asynchronous Mode.  
Synchronous Mode.  
XRCLK: This bit selects the clock source for the receiver  
section. Read/Write, cleared on reset.  
XRCLK = 0  
The clock source is selected through the  
PSR and BAUD registers.  
ENUR-USART Receive Control and Status Register  
(Address at 0BB)  
XRCLK = 1  
Signal on CKX (L1) pin is used as the clock.  
DOE FE PE Reserved RBIT9 ATTN XMTG RCVG  
(Note 12)  
XTCLK: This bit selects the clock source for the transmitter  
section. Read/Write, cleared on reset.  
Bit 7  
Bit 0  
XTCLK = 0  
The clock source is selected through the  
PSR and BAUD registers.  
Note 12: Bit is reserved for future use. User must set to zero.  
XTCLK = 1  
Signal on CKX (L1) pin is used as the clock.  
DOE: Flags a Data Overrun Error. Read only, cleared on  
read, cleared on reset.  
ERI: This bit enables/disables interrupt from the receiver  
section. Read/Write, cleared on reset.  
DOE = 0  
Indicates no Data Overrun Error has been de-  
tected since the last time the ENUR register  
was read.  
ERI = 0  
ERI = 1  
Interrupt from the receiver is disabled.  
Interrupt from the receiver is enabled.  
DOE = 1  
Indicates the occurrence of a Data Overrun Er-  
ror.  
ETI: This bit enables/disables interrupt from the transmitter  
section. Read/Write, cleared on reset.  
FE: Flags a Framing Error. Read only, cleared on read,  
cleared on reset.  
ETI = 0  
ETI = 1  
Interrupt from the transmitter is disabled.  
Interrupt from the transmitter is enabled.  
FE = 0  
FE = 1  
Indicates no Framing Error has been detected  
since the last time the ENUR register was read.  
Associated I/O Pins  
Indicates the occurrence of a Framing Error.  
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.  
PE: Flags a Parity Error. Read only, cleared on read, cleared  
on reset.  
PE = 0  
Indicates no Parity Error has been detected since  
the last time the ENUR register was read.  
PE = 1  
Indicates the occurrence of a Parity Error.  
The baud rate clock for the USART 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 Con-  
figuration 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.  
SPARE: Reserved for future use. Read/Write, cleared on re-  
set.  
RBIT9: Contains the ninth data bit received when the US-  
ART is operating with nine data bits per frame. Read only,  
cleared on reset.  
ATTN: ATTENTION Mode is enabled while this bit is set.  
This bit is cleared automatically on receiving a character with  
data bit nine set. Read/Write, cleared on reset.  
XMTG: This bit is set to indicate that the USART is transmit-  
ting. It gets reset at the end of the last frame (end of last Stop  
bit). Read only, cleared on reset.  
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26  
output at the CKX pin. The internal baud rate generator is  
used to produce the synchronous clock. Data transmit and  
receive are performed synchronously with this clock.  
USART Operation  
The USART has two modes of operation: asynchronous  
mode and synchronous mode.  
FRAMING FORMATS  
ASYNCHRONOUS MODE  
The USART supports several serial framing formats (Figure  
13). The format is selected using control bits in the ENU,  
ENUR and ENUI registers.  
This mode is selected by resetting the SSEL (in the ENUI  
register) bit to zero. The input frequency to the USART is 16  
times the baud rate.  
The first format (1, 1a, 1b, 1c) for data transmission (CHL0 =  
1, CHL1 = 0) consists of Start bit, seven Data bits (excluding  
parity) and 7/8, one or two Stop bits. In applications using  
parity, the parity bit is generated and verified by hardware.  
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 USART when software  
loads a new character into the TBUF register. There is also  
the XMTG bit which is set to indicate that the USART is  
transmitting. This bit gets reset at the end of the last frame  
(end of last Stop bit). TBUF is a read/write register.  
The second format (CHL0 = 0, CHL1 = 0) consists of one  
Start bit, eight Data bits (excluding parity) and 7/8, one or  
two Stop bits. Parity bit is generated and verified by hard-  
ware.  
The third format for transmission (CHL0 = 0, CHL1 = 1) con-  
sists of one Start bit, nine Data bits and 7/8, one or two Stop  
bits. This format also supports the USART “ATTENTION”  
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.  
The RSFT and RBUF registers double-buffer data being re-  
ceived. The USART 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 remaining  
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 complete  
character, the contents of the RSFT register are copied 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 reg-  
ister. There is also the RCVG bit which is set high when a  
framing error occurs and goes low once RDX goes high.  
TBMT, XMTG, RBFL and RCVG are read only bits.  
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. If par-  
ity is enabled (PEN = 1), the parity selection is then per-  
formed by PSEL0 and PSEL1 bits located in the ENU regis-  
ter.  
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 USART 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.  
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.  
The frame formats for the receiver differ from the transmitter  
in the number of Stop bits required. The receiver only re-  
quires one Stop bit in a frame, regardless of the setting of the  
Stop bit selection bits in the control register. Note that an im-  
plicit assumption is made for full duplex USART operation  
that the framing formats are the same for the transmitter and  
receiver.  
This mode is selected by setting SSEL bit in the ENUI regis-  
ter. The input frequency to the USART is the same as the  
baud rate.  
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.  
If data transmit and receive are selected with the CKX pin as  
clock output, the device generates the synchronous clock  
27  
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USART Operation (Continued)  
DS012829-15  
FIGURE 13. Framing Formats  
USART INTERRUPTS  
the basic baud clock is created from the oscillator frequency  
through a two-stage divider chain consisting of a 1–16 (in-  
crements of 0.5) prescaler and an 11-bit binary counter. (Fig-  
ure 14). The divide factors are specified through two read/  
write registers shown in Figure 15. Note that the 11-bit Baud  
Rate Divisor spills over into the Prescaler Select Register  
(PSR). PSR is cleared upon reset.  
The USART is capable of generating interrupts. Interrupts  
are generated on Receive Buffer Full and Transmit Buffer  
Empty. 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 6, a Prescaler Factor of 0 corresponds to  
NO CLOCK. This condition is the USART power down mode  
where the USART clock is turned off for power saving pur-  
pose. The user must also turn the USART 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 6. There 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 pres-  
caler output is then used to drive the software programmable  
baud rate counter to create a 16x clock for the following baud  
rates: 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 3600,  
4800, 7200, 9600, 19200 and 38400 (Table 1). Other baud  
rates may be created by using appropriate divisors. The 16x  
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 USART can be individually selected to come either from  
an external source at the CKX pin (port L, pin L1) or from a  
source selected in the PSR and BAUD registers. Internally,  
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28  
Baud Clock Generation (Continued)  
DS012829-16  
FIGURE 14. USART BAUD Clock Generation  
DS012829-17  
FIGURE 15. USART BAUD Clock Divisor Registers  
TABLE 3. Baud Rate Divisors  
(1.8432 MHz Prescaler Output)  
Prescaler  
Select  
01000  
01001  
01010  
01011  
01100  
01101  
01110  
01111  
10000  
10001  
10010  
10011  
10100  
10101  
10110  
10111  
11000  
11001  
11010  
11011  
11100  
11101  
11110  
11111  
Prescaler  
Factor  
4.5  
5
Baud  
Rate  
Baud Rate  
Divisor − 1  
(N-1)  
5.5  
6
110  
1046  
(110.03)  
6.5  
7
134.5  
855  
(134.58)  
7.5  
8
150  
300  
767  
383  
191  
95  
63  
47  
31  
23  
15  
11  
5
8.5  
9
600  
1200  
1800  
2400  
3600  
4800  
7200  
9600  
19200  
38400  
9.5  
10  
10.5  
11  
11.5  
12  
12.5  
13  
2
13.5  
14  
Note: The entries in Table 4 assume a prescaler output of 1.8432 MHz. In the  
asynchronous mode the baud rate could be as high as 625k.  
14.5  
15  
TABLE 4. Prescaler Factors  
Prescaler  
Select  
00000  
00001  
00010  
00011  
00100  
00101  
00110  
00111  
Prescaler  
15.5  
16  
Factor  
NO CLOCK  
1
1.5  
2
2.5  
3
3.5  
4
29  
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cause of the finite start up time requirement of the crystal os-  
cillator. The idle timer (T0) generates a fixed (256 tc) delay to  
ensure that the oscillator has indeed stabilized before allow-  
ing the device to execute code. The user has to consider this  
delay when data transfer is expected immediately after exit-  
ing the HALT mode.  
Baud Clock Generation (Continued)  
As an example, considering Asynchronous Mode and a CKI  
clock of 4.608 MHz, the prescaler factor selected is:  
4.608/1.8432 = 2.5  
The 2.5 entry is available in Table 4. The 1.8432 MHz pres-  
caler output is then used with proper Baud Rate Divisor  
(Table 3) to obtain different baud rates. For a baud rate of  
19200 e.g., the entry in Table 3 is 5.  
Diagnostic  
Bits CHARL0 and CHARL1 in the ENU register provide a  
loopback feature for diagnostic testing of the USART. When  
these bits are set to one, the following occur: The receiver in-  
put pin (RDX) is internally connected to the transmitter out-  
put pin (TDX); the output of the Transmitter Shift Register 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 re-  
ceive data paths of the USART.  
N − 1 = 5 (N − 1 is the value from Table 3)  
N = 6 (N is the Baud Rate Divisor)  
Baud Rate = 1.8432 MHz/(16 x 6) = 19200  
The divide by 16 is performed because in the asynchronous  
mode, the input frequency to the USART is 16 times the  
baud rate. The equation to calculate baud rates is given be-  
low.  
The actual Baud Rate may be found from:  
BR = Fc/(16 x N x P)  
Note that the framing format for this mode is the nine bit for-  
mat; one Start bit, nine data bits, and 7/8, one or two Stop  
bits. Parity is not generated or verified in this mode.  
Where:  
BR is the Baud Rate  
Attention Mode  
Fc is the CKI frequency  
N is the Baud Rate Divisor (Table 3).  
The USART 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 4)  
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:  
Crystal Frequency = 5 MHz  
Desired baud rate = 9600  
Using the above equation N x P can be calculated first.  
N x P = (5 x 106)/(16 x 9600) = 32.552  
Now 32.552 is divided by each Prescaler Factor (Table 4) to  
obtain a value closest to an integer. This factor happens to  
be 6.5 (P = 6.5).  
While in ATTENTION mode, the USART monitors the com-  
munication flow, but ignores all characters until an address  
character is received. Upon receiving an address character,  
the USART signals that the character is ready by setting the  
RBFL flag, which in turn interrupts the processor if USART  
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 examines the  
contents of the RBUF and responds by deciding either to ac-  
cept the subsequent data stream (by leaving the ATTN bit re-  
set) or to wait until the next address character is seen (by  
setting the ATTN bit again).  
N = 32.552/6.5 = 5.008 (N = 5)  
The programmed value (from Table 3) should be 4 (N − 1).  
Using the above values calculated for N and P:  
BR = (5 x 106)/(16 x 5 x 6.5) = 9615.384  
% error = (9615.385 − 9600)/9600 x 100 = 0.16%  
Effect of HALT/IDLE  
The USART 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 USART 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 registers  
RBUF and RSFT are not affected.  
Operation of the USART 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 re-  
side, 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  
I1–I3 and I4–I6 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 register  
(Bit 3 is one.)  
I6 Comparator2 output  
I5 Comparator2 positive input  
I4 Comparator2 negative input  
I3 Comparator1 output  
If the device is halted and crystal oscillator is used, the  
Wakeup signal will not start the chip running immediately be-  
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30  
bit are associated with each comparator. The comparator re-  
sult bits (CMP1RD and CMP2RD) are read only bits which  
will read as zero if the associated comparator is not enabled.  
The Comparator Select Register is cleared with reset, result-  
ing in the comparators being disabled. The comparators  
should also be disabled before entering either the HALT or  
IDLE modes in order to save power. The configuration of the  
CMPSL register is as follows:  
Comparators (Continued)  
I2 Comparator1 positive input  
I1 Comparator1 negative input  
Only Comparator 1 is available on the CS series.  
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  
CMPSL REGISTER (ADDRESS X’00B7)  
Reserved  
Bit 7  
CMP20E  
CMP2RD  
CMP2EN  
CMP10E  
CMP1RD  
CMP1EN  
Reserved  
Bit 0  
The CMPSL register contains the following bits:  
Interrupts  
Reserved These bits are reserved and must be zero  
INTRODUCTION  
CMP20E Selects pin I6 as comparator 2 output provided  
that CMP2EN is set to enable the comparator  
Each device supports thirteen vectored interrupts. Interrupt  
sources include Timer 0, Timer 1, Timer 2, Timer 3, Port L  
Wakeup, Software Trap, MICROWIRE/PLUS, and External  
Input.  
CMP2RD Comparator 2 result (this is a read only bit, which  
will read as 0 if the comparator is not enabled)  
CMP2EN Enable comparator 2  
All interrupts force a branch to location 00FF Hex in program  
memory. The VIS instruction may be used to vector to the  
appropriate service routine from location 00FF Hex.  
CMP10E Selects pin I3 as comparator 1 output provided  
that CMPIEN is set to enable the comparator  
CMP1RD Comparator 1 result (this is a read only bit, which  
will read as 0 if the comparator is not enabled)  
The Software trap has the highest priority while the default  
VIS has the lowest priority.  
CMP1EN Enable comparator 1  
Each of the 13 maskable inputs has a fixed arbitration rank-  
ing and vector.  
Note: For compatibility with existing code and with existing Mask ROMMed  
devices the bits of the CMPSL register will take precedence over the  
associated Port F configuration and data output bits.  
Figure 16 shows the Interrupt Block Diagram.  
DS012829-42  
FIGURE 16. Interrupt Block Diagram  
31  
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interrupt, and jump to the interrupt handling routine corre-  
sponding to the highest priority enabled and active interrupt.  
Alternately, the user may choose to poll all interrupt pending  
and enable bits to determine the source(s) of the interrupt. If  
more than one interrupt is active, the user’s program must  
decide which interrupt to service.  
Interrupts (Continued)  
MASKABLE INTERRUPTS  
All interrupts other than the Software Trap are maskable.  
Each maskable interrupt has an associated enable bit and  
pending flag bit. The pending bit is set to 1 when the interrupt  
condition occurs. The state of the interrupt enable bit, com-  
bined with the GIE bit determines whether an active pending  
flag actually triggers an interrupt. All of the maskable inter-  
rupt pending and enable bits are contained in mapped con-  
trol registers, and thus can be controlled by the software.  
Within a specific interrupt service routine, the associated  
pending bit should be cleared. This is typically done as early  
as possible in the service routine in order to avoid missing  
the next occurrence of the same type of interrupt event.  
Thus, if the same event occurs a second time, even while the  
first occurrence is still being serviced, the second occur-  
rence will be serviced immediately upon return from the cur-  
rent interrupt routine.  
A maskable interrupt condition triggers an interrupt under the  
following conditions:  
1. The enable bit associated with that interrupt is set.  
2. The GIE bit is set.  
An interrupt service routine typically ends with an RETI in-  
struction. This instruction sets the GIE bit back to 1, pops the  
address stored on the stack, and restores that address to the  
program counter. Program execution then proceeds with the  
next instruction that would have been executed had there  
been no interrupt. If there are any valid interrupts pending,  
the highest-priority interrupt is serviced immediately upon re-  
turn from the previous interrupt.  
3. The device is not processing a non-maskable interrupt.  
(If  
a non-maskable interrupt is being serviced, a  
maskable interrupt must wait until that service routine is  
completed.)  
An interrupt is triggered only when all of these conditions are  
met at the beginning of an instruction. If different maskable  
interrupts meet these conditions simultaneously, the highest  
priority interrupt will be serviced first, and the other pending  
interrupts must wait.  
VIS INSTRUCTION  
The general interrupt service routine, which starts at address  
00FF Hex, must be capable of handling all types of inter-  
rupts. The VIS instruction, together with an interrupt vector  
table, directs the device to the specific interrupt handling rou-  
tine based on the cause of the interrupt.  
Upon Reset, all pending bits, individual enable bits, and the  
GIE bit are reset to zero. Thus, a maskable interrupt condi-  
tion cannot trigger an interrupt until the program enables it by  
setting both the GIE bit and the individual enable bit. When  
enabling an interrupt, the user should consider whether or  
not a previously activated (set) pending bit should be ac-  
knowledged. If, at the time an interrupt is enabled, any pre-  
vious occurrences of the interrupt should be ignored, the as-  
sociated pending bit must be reset to zero prior to enabling  
the interrupt. Otherwise, the interrupt may be simply en-  
abled; if the pending bit is already set, it will immediately trig-  
ger an interrupt. A maskable interrupt is active if its associ-  
ated enable and pending bits are set.  
VIS is a single-byte instruction, typically used at the very be-  
ginning of the general interrupt service routine at address  
00FF Hex, or shortly after that point, just after the code used  
for context switching. The VIS instruction determines which  
enabled and pending interrupt has the highest priority, and  
causes an indirect jump to the address corresponding to that  
interrupt source. The jump addresses (vectors) for all pos-  
sible interrupts sources are stored in a vector table.  
The vector table may be as long as 32 bytes (maximum of 16  
vectors) and resides at the top of the 256-byte block contain-  
ing the VIS instruction. However, if the VIS instruction is at  
the very top of a 256-byte block (such as at 00FF Hex), the  
vector table resides at the top of the next 256-byte block.  
Thus, if the VIS instruction is located somewhere between  
00FF and 01DF Hex (the usual case), the vector table is lo-  
cated between addresses 01E0 and 01FF Hex. If the VIS in-  
struction is located between 01FF and 02DF Hex, then the  
vector table is located between addresses 02E0 and 02FF  
Hex, and so on.  
An interrupt is an asychronous event which may occur be-  
fore, during, or after an instruction cycle. Any interrupt which  
occurs during the execution of an instruction is not acknowl-  
edged until the start of the next normally executed instruction  
is to be skipped, the skip is performed before the pending in-  
terrupt is acknowledged.  
At the start of interrupt acknowledgment, the following ac-  
tions occur:  
1. The GIE bit is automatically reset to zero, preventing any  
subsequent maskable interrupt from interrupting the cur-  
rent service routine. This feature prevents one maskable  
interrupt from interrupting another one being serviced.  
Each vector is 15 bits long and points to the beginning of a  
specific interrupt service routine somewhere in the 32 kbyte  
memory space. Each vector occupies two bytes of the vector  
table, with the higher-order byte at the lower address. The  
vectors are arranged in order of interrupt priority. The vector  
of the maskable interrupt with the lowest rank is located to  
0yE0 (higher-order byte) and 0yE1 (lower-order byte). The  
next priority interrupt is located at 0yE2 and 0yE3, and so  
forth in increasing rank. The Software Trap has the highest  
rank and its vector is always located at 0yFE and 0yFF. The  
number of interrupts which can become active defines the  
size of the table.  
2. The address of the instruction about to be executed is  
pushed onto the stack.  
3. The program counter (PC) is loaded with 00FF Hex,  
causing a jump to that program memory location.  
The device requires seven instruction cycles to perform the  
actions listed above.  
If the user wishes to allow nested interrupts, the interrupts  
service routine may set the GIE bit to 1 by writing to the PSW  
register, and thus allow other maskable interrupts to interrupt  
the current service routine. If nested interrupts are allowed,  
caution must be exercised. The user must write the program  
in such a way as to prevent stack overflow, loss of saved  
context information, and other unwanted conditions.  
Table 5 shows the types of interrupts, the interrupt arbitration  
ranking, and the locations of the corresponding vectors in  
the vector table.  
The vector table should be filled by the user with the memory  
locations of the specific interrupt service routines. For ex-  
The interrupt service routine stored at location 00FF Hex  
should use the VIS instruction to determine the cause of the  
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32  
gram context (A, B, X, etc.) and executing the RETI instruc-  
tion, an interrupt service routine can be terminated by return-  
ing to the VIS instruction. In this case, interrupts will be  
serviced in turn until no further interrupts are pending and  
the default VIS routine is started. After testing the GIE bit to  
ensure that execution is not erroneous, the routine should  
restore the program context and execute the RETI to return  
to the interrupted program.  
Interrupts (Continued)  
ample, if the Software Trap routine is located at 0310 Hex,  
then the vector location 0yFE and -0yFF should contain the  
data 03 and 10 Hex, respectively. When a Software Trap in-  
terrupt occurs and the VIS instruction is executed, the pro-  
gram jumps to the address specified in the vector table.  
The interrupt sources in the vector table are listed in order of  
rank, from highest to lowest priority. If two or more enabled  
and pending interrupts are detected at the same time, the  
one with the highest priority is serviced first. Upon return  
from the interrupt service routine, the next highest-level  
pending interrupt is serviced.  
This technique can save up to fifty instruction cycles (t  
c), or  
more, (50µs at 10 MHz oscillator) of latency for pending in-  
terrupts with a penalty of fewer than ten instruction cycles if  
no further interrupts are pending.  
To ensure reliable operation, the user should always use the  
VIS instruction to determine the source of an interrupt. Al-  
though it is possible to poll the pending bits to detect the  
source of an interrupt, this practice is not recommended. The  
use of polling allows the standard arbitration ranking to be al-  
tered, but the reliability of the interrupt system is compro-  
mised. The polling routine must individually test the enable  
and pending bits of each maskable interrupt. If a Software  
Trap interrupt should occur, it will be serviced last, even  
though it should have the highest priority. Under certain con-  
ditions, a Software Trap could be triggered but not serviced,  
resulting in an inadvertent “locking out” of all maskable inter-  
rupts by the Software Trap pending flag. Problems such as  
this can be avoided by using VIS instruction.  
If the VIS instruction is executed, but no interrupts are en-  
abled and pending, the lowest-priority interrupt vector is  
used, and a jump is made to the corresponding address in  
the vector table. This is an unusual occurrence, and may be  
the result of an error. It can legitimately result from a change  
in the enable bits or pending flags prior to the execution of  
the VIS instruction, such as executing a single cycle instruc-  
tion which clears an enable flag at the same time that the  
pending flag is set. It can also result, however, from inadvert-  
ent execution of the VIS command outside of the context of  
an interrupt.  
The default VIS interrupt vector can be useful for applica-  
tions in which time critical interrupts can occur during the  
servicing of another interrupt. Rather than restoring the pro-  
TABLE 5. Interrupt Vector Table  
Vector Address (Note *NO  
TARGET FOR FNXref NS7955*)  
(Hi-Low Byte)  
0yFE–0yFF  
Arbitration  
Source  
Description  
Ranking  
(1) Highest  
(2)  
Software  
INTR Instruction  
Reserved  
External  
0yFC–0yFD  
(3)  
G0  
0yFA–0yFB  
(4)  
Timer T0  
Underflow  
T1A/Underflow  
T1B  
0yF8–0yF9  
(5)  
Timer T1  
0yF6–0yF7  
(6)  
Timer T1  
0yF4–0yF5  
(7)  
MICROWIRE/PLUS  
Reserved  
UART  
BUSY Low  
0yF2–0yF3  
(8)  
0yF0–0yF1  
(9)  
Receive  
0yEE–0yEF  
(10)  
(11)  
(12)  
(13)  
(14)  
(15)  
(16) Lowest  
UART  
Transmit  
T2A/Underflow  
T2B  
0yEC–0yED  
Timer T2 *  
Timer T2 *  
Timer T3 *  
Timer T3 *  
Port L/Wakeup  
Default VIS  
0yEA–0yEB  
0yE8–0yE9  
T2A/Underflow  
T3B  
0yE6–0yE7  
0yE4–0yE5  
Port L Edge  
Reserved  
0yE2–0yE3  
0yE0–0yE1  
Note 13: y is a variable which represents the VIS block. VIS and the vector table must be located in the same 256-byte block except if VIS is located at the last ad-  
dress of a block. In this case, the table must be in the next block.  
*
Reserved on the CS series.  
33  
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Interrupts (Continued)  
VIS Execution  
When the VIS instruction is executed it activates the arbitra-  
tion logic. The arbitration logic generates an even number  
between E0 and FE (E0, E2, E4, E6 etc...) depending on  
which active interrupt has the highest arbitration ranking at  
the time of the 1st cycle of VIS is executed. For example, if  
the software trap interrupt is active, FE is generated. If the  
external interrupt is active and the software trap interrupt is  
not, then FA is generated and so forth. If the only active inter-  
rupt is software trap, than E0 is generated. This number re-  
places the lower byte of the PC. The upper byte of the PC re-  
mains unchanged. The new PC is therefore pointing to the  
vector of the active interrupt with the highest arbitration rank-  
ing. This vector is read from program memory and placed  
into the PC which is now pointed to the 1st instruction of the  
service routine of the active interrupt with the highest arbitra-  
tion ranking.  
Figure 17 illustrates the different steps performed by the VIS  
instruction. Figure 18 shows a flowchart for the VIS instruc-  
tion.  
The non-maskable interrupt pending flag is cleared by the  
RPND (Reset Non-Maskable Pending Bit) instruction (under  
certain conditions) and upon RESET.  
DS012829-43  
FIGURE 17. VIS Operation  
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34  
Interrupts (Continued)  
DS012829-44  
FIGURE 18. VIS Flowchart  
35  
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Interrupts (Continued)  
Programming Example: External Interrupt  
PSW  
CNTRL  
RBIT  
RBIT  
SBIT  
SBIT  
SBIT  
JP  
=00EF  
=00EE  
0,PORTGC  
0,PORTGD  
IEDG, CNTRL  
EXEN, PSW  
GIE, PSW  
WAIT  
; G0 pin configured Hi-Z  
; Ext interrupt polarity; falling edge  
; Enable the external interrupt  
; Set the GIE bit  
WAIT:  
; Wait for external interrupt  
.
.
.
.=0FF  
VIS  
; The interrupt causes a  
; branch to address 0FF  
; The VIS causes a branch to  
;interrupt vector table  
.
.
.
.=01FA  
.ADDRW SERVICE  
; Vector table (within 256 byte  
; of VIS inst.) containing the ext  
; interrupt service routine  
.
.
INT_EXIT:  
SERVICE:  
RETI  
.
.
RBIT  
EXPND, PSW  
; Interrupt Service Routine  
; Reset ext interrupt pend. bit  
.
.
.
JP  
INT_EXIT  
; Return, set the GIE bit  
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36  
flag; upon return to the first Software Trap routine, the  
STPND flag will have the wrong state. This will allow  
maskable interrupts to be acknowledged during the servicing  
of the first Software Trap. To avoid problems such as this, the  
user program should contain the Software Trap routine to  
perform a recovery procedure rather than a return to normal  
execution.  
Interrupts (Continued)  
NON-MASKABLE INTERRUPT  
Pending Flag  
There is a pending flag bit associated with the non-maskable  
interrupt, called STPND. This pending flag is not memory-  
mapped and cannot be accessed directly by the software.  
Under normal conditions, the STPND flag is reset by a  
RPND instruction in the Software Trap service routine. If a  
programming error or hardware condition (brownout, power  
supply glitch, etc.) sets the STPND flag without providing a  
way for it to be cleared, all other interrupts will be locked out.  
To alleviate this condition, the user can use extra RPND in-  
structions in the main program and in the WATCHDOG ser-  
vice routine (if present). There is no harm in executing extra  
RPND instructions in these parts of the program.  
The pending flag is reset to zero when a device Reset oc-  
curs. When the non-maskable interrupt occurs, the associ-  
ated pending bit is set to 1. The interrupt service routine  
should contain an RPND instruction to reset the pending flag  
to zero. The RPND instruction always resets the STPND  
flag.  
Software Trap  
The Software Trap is a special kind of non-maskable inter-  
rupt which occurs when the INTR instruction (used to ac-  
knowledge interrupts) is fetched from program memory and  
placed in the instruction register. This can happen in a vari-  
ety of ways, usually because of an error condition. Some ex-  
amples of causes are listed below.  
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 speci-  
fies the trigger condition to be either a positive or a negative  
edge. Finally, the register WKPND latches in the pending  
trigger conditions.  
If the program counter incorrectly points to a memory loca-  
tion beyond the available program memory space, the non-  
existent or unused memory location returns zeroes which is  
interpreted as the INTR instruction.  
If the stack is popped beyond the allowed limit (address 06F  
Hex), a 7FFF will be loaded into the PC, if this last location in  
program memory is unprogrammed or unavailable, a Soft-  
ware Trap will be triggered.  
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.  
A Software Trap can be triggered by a temporary hardware  
condition such as a brownout or power supply glitch.  
The Software Trap has the highest priority of all interrupts.  
When a Software Trap occurs, the STPND bit is set. The GIE  
bit is not affected and the pending bit (not accessible by the  
user) is used to inhibit other interrupts and to direct the pro-  
gram to the ST service routine with the VIS instruction. Noth-  
ing can interrupt a Software Trap service routine except for  
another Software Trap. The STPND can be reset only by the  
RPND instruction or a chip Reset.  
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 ex-  
ecution 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 in-  
terrupt service routine and then revert to normal operation.  
(See HALT MODE for clock option wakeup information.)  
The Software Trap indicates an unusual or unknown error  
condition. Generally, returning to normal execution at the  
point where the Software Trap occurred cannot be done re-  
liably. Therefore, the Software Trap service routine should  
reinitialize the stack pointer and perform a recovery proce-  
dure that restarts the software at some known point, similar  
to a device Reset, but not necessarily performing all the  
same functions as a device Reset. The routine must also ex-  
ecute the RPND instruction to reset the STPND flag. Other-  
wise, all other interrupts will be locked out. To the extent pos-  
sible, the interrupt routine should record or indicate the  
context of the device so that the cause of the Software Trap  
can be determined.  
INTERRUPT SUMMARY  
The device uses the following types of interrupts, listed be-  
low in order of priority:  
1. The Software Trap non-maskable interrupt, triggered by  
the INTR (00 opcode) instruction. The Software Trap is  
acknowledged immediately. This interrupt service rou-  
tine can be interrupted only by another Software Trap.  
The Software Trap should end with two RPND instruc-  
tions followed by a restart procedure.  
2. Maskable interrupts, triggered by an on-chip peripheral  
block or an external device connected to the device. Un-  
der ordinary conditions, a maskable interrupt will not in-  
If the user wishes to return to normal execution from the  
point at which the Software Trap was triggered, the user  
must first execute RPND, followed by RETSK rather than  
RETI or RET. This is because the return address stored on  
the stack is the address of the INTR instruction that triggered  
the interrupt. The program must skip that instruction in order  
to proceed with the next one. Otherwise, an infinite loop of  
Software Traps and returns will occur.  
terrupt any other interrupt routine in progress.  
maskable interrupt routine in progress can be inter-  
rupted by the non-maskable interrupt request.  
maskable interrupt routine should end with an RETI in-  
struction or, prior to restoring context, should return to  
execute the VIS instruction. This is particularly useful  
when exiting long interrupt service routiness if the time  
between interrupts is short. In this case the RETI instruc-  
tion would only be executed when the default VIS rou-  
tine is reached.  
A
A
Programming a return to normal execution requires careful  
consideration. If the Software Trap routine is interrupted by  
another Software Trap, the RPND instruction in the service  
routine for the second Software Trap will reset the STPND  
37  
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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.  
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 specified  
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 reg-  
ister 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 in-  
volves selecting or deselecting the Clock Monitor, select the  
WATCHDOG service window and match the WATCHDOG  
key data. Subsequent writes to the WDSVR register will  
compare the value being written by the user to the WATCH-  
DOG service window value and the key data (bits 7 through  
1) in the WDSVR Register. Table 8 shows the sequence 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  
value to a WATCHDOG Service Register named WDSVR  
which is memory mapped in the RAM. This value is com-  
posed of three fields, consisting of a 2-bit Window Select, a  
5-bit Key Data field, and the 1-bit Clock Monitor Select field.  
Table 6 shows the WDSVR register.  
The user must service the WATCHDOG at least once before  
the upper limit of the service window expires. The WATCH-  
DOG may not be serviced more than once in every lower  
limit of the service window. The user may service the  
WATCHDOG as many times as wished in the time period be-  
tween the lower and upper limits of the service window. The  
first write to the WDSVR Register is also counted as a  
WATCHDOG service.  
TABLE 6. WATCHDOG Service Register (WDSVR)  
Window  
Select  
Key Data  
Clock  
Monitor  
X
X
6
0
5
1
4
1
3
0
2
0
1
Y
0
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 in-  
active state. Upon triggering the WATCHDOG, the logic will  
pull the WDOUT (G1) pin low for an additional 16 tc–32 tc  
cycles after the signal level on WDOUT pin goes below the  
lower Schmitt trigger threshold. After this delay, the device  
will stop forcing the WDOUT output low.  
7
The lower limit of the service window is fixed at 2048 instruc-  
tion cycles. Bits 7 and 6 of the WDSVR register allow the  
user to pick an upper limit of the service window.  
Table 7 shows the four possible combinations of lower and  
upper limits for the WATCHDOG service window. This flex-  
ibility in choosing the WATCHDOG service window prevents  
any undue burden on the user software.  
The WATCHDOG service window will restart when the WD-  
OUT pin goes high. It is recommended that the user tie the  
WDOUT pin back to VCC through a resistor in order to pull  
WDOUT high.  
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.  
A WATCHDOG service while the WDOUT signal is active will  
be ignored. The state of the WDOUT pin is not guaranteed  
on reset, but if it powers up low then the WATCHDOG will  
time out and WDOUT will enter high impedance state.  
TABLE 7. WATCHDOG Service Window Select  
WDSVR WDSVR  
Clock  
Service Window  
(Lower-Upper Limits)  
2048–8k tC Cycles  
Bit 7  
Bit 6  
Monitor  
The Clock Monitor forces the G1 pin low upon detecting a  
clock frequency error. The Clock Monitor error will continue  
until the clock frequency has reached the minimum specified  
value, after which the G1 output will enter the high imped-  
ance TRI-STATE mode following 16 tc–32 tc clock cycles.  
The Clock Monitor generates a continual Clock Monitor error  
if the oscillator fails to start, or fails to reach the minimum  
specified frequency. The specification for the Clock Monitor  
is as follows:  
0
0
1
1
x
x
0
1
0
1
x
x
x
x
x
x
0
1
2048–16k tC Cycles  
2048–32k tC Cycles  
2048–64k tC Cycles  
Clock Monitor Disabled  
Clock Monitor Enabled  
>
1/tc 10 kHzNo clock rejection.  
Clock Monitor  
<
1/tc 10 HzGuaranteed clock rejection.  
The Clock Monitor aboard the device can be selected or de-  
selected under program control. The Clock Monitor is guar-  
anteed not to reject the clock if the instruction cycle clock (1/  
tc) is greater or equal to 10 kHz. This equates to a clock input  
rate on CKI of greater or equal to 100 kHz.  
WATCHDOG AND CLOCK MONITOR SUMMARY  
The following salient points regarding the WATCHDOG and  
CLOCK MONITOR should be noted:  
Both the WATCHDOG and CLOCK MONITOR detector  
circuits are inhibited during RESET.  
WATCHDOG Operation  
Following RESET, the WATCHDOG and CLOCK MONI-  
TOR are both enabled, with the WATCHDOG having he  
maximum service window selected.  
The WATCHDOG and Clock Monitor are disabled during re-  
set. 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  
The WATCHDOG service window and CLOCK MONI-  
TOR enable/disable option can only be changed once,  
during the initial WATCHDOG service following RESET.  
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38  
The subroutine stack grows down for each call (jump to sub-  
routine), interrupt, or PUSH, and grows up for each return or  
POP. The stack pointer is initialized to RAM location 06F Hex  
during reset. Consequently, if there are more returns than  
calls, the stack pointer will point to addresses 070 and 071  
Hex (which are undefined RAM). Undefined RAM from ad-  
dresses 070 to 07F (Segment 0), and all other segments  
(i.e., Segments 4 … 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 location will generate a software interrupt signaling  
an illegal condition.  
WATCHDOG Operation (Continued)  
The initial WATCHDOG service must match the key data  
value in the WATCHDOG Service register WDSVR in or-  
der to avoid a WATCHDOG error.  
Subsequent WATCHDOG services must match all three  
data fields in WDSVR in order to avoid WATCHDOG er-  
rors.  
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.  
Thus, the chip can detect the following illegal conditions:  
1. Executing from undefined ROM  
The WATCHDOG detector circuit is inhibited during both  
the HALT and IDLE modes.  
2. Over “POP”ing the stack by having more returns than  
calls.  
The CLOCK MONITOR detector circuit is active during  
both the HALT and IDLE modes. Consequently, the de-  
vice inadvertently entering the HALT mode will be de-  
tected as a CLOCK MONITOR error (provided that the  
CLOCK MONITOR enable option has been selected by  
the program).  
When the software interrupt occurs, the user can re-initialize  
the stack pointer and do a recovery procedure before restart-  
ing (this recovery program is probably similar to that follow-  
ing reset, but might not contain the same program initializa-  
tion procedures). The recovery program should reset the  
software interrupt pending bit using the RPND instruction.  
With the single-pin R/C oscillator 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.  
MICROWIRE/PLUS  
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.  
MICROWIRE/PLUS is a serial synchronous communications  
interface. The MICROWIRE/PLUS capability enables the de-  
vice to interface with any of National Semiconductor’s MI-  
CROWIRE peripherals (i.e. A/D converters, display drivers,  
E2PROMs etc.) and with other microcontrollers which sup-  
port the MICROWIRE interface. It consists of an 8-bit serial  
shift register (SIO) with serial data input (SI), serial data out-  
put (SO) and serial shift clock (SK). Figure 19 shows a block  
diagram of the MICROWIRE/PLUS logic.  
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.  
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 se-  
lected window 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 initial  
WATCHDOG service may be programmed within the ini-  
tial 2048 instruction cycles without causing a WATCH-  
DOG error.  
DS012829-19  
FIGURE 19. MICROWIRE/PLUS Block Diagram  
The shift clock can be selected from either an internal source  
or an external source. Operating the MICROWIRE/PLUS ar-  
rangement 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.  
Detection of Illegal Conditions  
The device can detect various illegal conditions resulting  
from coding errors, transient noise, power supply voltage  
drops, runaway programs, etc.  
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 mas-  
ter mode, the SK clock rate is selected by the two bits, SL0  
and SL1, in the CNTRL register. Table 9 details the different  
clock rates that may be selected.  
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.  
39  
www.national.com  
MICROWIRE/PLUS (Continued)  
TABLE 8. WATCHDOG Service Actions  
Key  
Window  
Clock  
Monitor  
Match  
Action  
Data  
Data  
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  
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 re-  
setting the appropriate bits in the Port G configuration regis-  
ter. Table 10 summarizes the settings required to enter the  
Slave mode of operation.  
TABLE 9. MICROWIRE/PLUS  
Master Mode Clock Select  
SL1  
0
SL0  
SK  
0
1
x
2 x tc  
4 x tc  
8 x tc  
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 re-  
peated.  
0
1
Where tc is the instruction cycle clock  
MICROWIRE/PLUS OPERATION  
Setting the BUSY bit in the PSW register causes the  
MICROWIRE/PLUS to start shifting the data. It gets reset  
when eight data bits have been shifted. The user may reset  
the BUSY bit by software to allow less than 8 bits to shift. If  
enabled, an interrupt is generated when eight data bits have  
been shifted. The device may enter the MICROWIRE/PLUS  
mode either as a Master or as a Slave. Figure 20 shows how  
two microcontroller devices and several peripherals may be  
interconnected using the MICROWIRE/PLUS arrangements.  
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 shifted in on the  
falling edge of the SK clock and shifted out on the rising edge  
of the SK clock.  
Warning:  
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.  
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 nor-  
mally low when not shifting.  
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.  
TABLE 10. MICROWIRE/PLUS Mode Settings  
This table assumes that the control flag MSEL is set.  
MICROWIRE/PLUS Master Mode Operation  
In the MICROWIRE/PLUS Master mode of operation the  
shift clock (SK) is generated internally by the device. The MI-  
CROWIRE 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 10 summarizes the  
bit settings required for Master mode of operation.  
G4 (SO)  
Config. Bit  
1
G5 (SK)  
Config. Bit  
1
G4  
Fun.  
SO  
G5  
Fun.  
Int.  
Operation  
MICROWIRE/PLUS  
Master  
SK  
0
1
0
1
0
0
TRI-  
STATE  
SO  
Int.  
MICROWIRE/PLUS  
Master  
SK  
Ext. MICROWIRE/PLUS  
SK Slave  
Ext. MICROWIRE/PLUS  
SK Slave  
MICROWIRE/PLUS Slave Mode Operation  
TRI-  
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  
STATE  
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40  
MICROWIRE/PLUS (Continued)  
DS012829-20  
FIGURE 20. MICROWIRE/PLUS Application  
Memory Map  
All RAM, ports and registers (except A and PC) are mapped into data memory address space.  
Address  
Contents  
Address  
Contents  
S/ADD REG  
S/ADD REG  
0000 to 006F  
0070 to 007F  
xxBC  
UART Interrupt and Clock Source  
Register (Reg:ENUI)  
On-Chip RAM bytes (112 bytes)  
Unused RAM Address Space (Reads As  
All Ones)  
xxBD  
xxBE  
UART Baud Register (Reg:BAUD)  
UART Prescale Select Register  
(Reg:PSR)  
xx80 to xx93  
Unused RAM Address Space (Reads  
Undefined Data)  
xxBF  
xxC0  
xxC1  
xxC2  
Reserved for UART  
Timer T2 Lower Byte  
Timer T2 Upper Byte  
xx94  
Port F data register, PORTFD  
xx95  
Port F configuration register, PORTFC  
Port F input pins (read only), PORTFP  
xx96  
Timer T2 Autoload Register T2RA Lower  
Byte  
xx97 to xxAF  
Unused address space (Reads  
Undefined Data)  
xxC3  
xxC4  
xxC5  
Timer T2 Autoload Register T2RA Upper  
Byte  
xxB0  
xxB1  
xxB2  
Timer T3 Lower Byte  
Timer T3 Upper Byte  
Timer T2 Autoload Register T2RB Lower  
Byte  
Timer T3 Autoload Register T3RA Lower  
Byte  
Timer T2 Autoload Register T2RB Upper  
Byte  
xxB3  
xxB4  
xxB5  
Timer T3 Autoload Register T3RA Upper  
Byte  
xxC6  
xxC7  
Timer T2 Control Register  
Timer T3 Autoload Register T3RB Lower  
Byte  
WATCHDOG Service Register  
(Reg:WDSVR)  
Timer T3 Autoload Register T3RB Upper  
Byte  
xxC8  
MIWU Edge Select Register  
(Reg:WKEDG)  
xxB6  
xxB7  
Timer T3 Control Register  
xxC9  
xxCA  
MIWU Enable Register (Reg:WKEN)  
MIWU Pending Register (Reg:WKPND)  
Comparator Select Register  
(Reg:CMPSL)  
xxCB to xxCF Reserved  
xxB8  
xxB9  
xxBA  
UART Transmit Buffer (Reg:TBUF)  
UART Receive Buffer (Reg:RBUF)  
xxD0  
xxD1  
xxD2  
xxD3  
xxD4  
xxD5  
Port L Data Register  
Port L Configuration Register  
Port L Input Pins (Read Only)  
Reserved for Port L  
UART Control and Status Register  
(Reg:ENU)  
xxBB  
UART Receive Control and Status  
Register (Reg:ENUR)  
Port G Data Register  
Port G Configuration Register  
41  
www.national.com  
Memory Map (Continued)  
Address  
S/ADD REG  
xxEC  
Contents  
Address  
Contents  
Timer T1 Autoload Register T1RA Lower  
Byte  
S/ADD REG  
xxD6  
xxD7  
Port G Input Pins (Read Only)  
xxED  
Timer T1 Autoload Register T1RA Upper  
Byte  
Port I Input Pins (Read Only) (Actually  
reads Port F input pins)  
xxEE  
CNTRL Control Register  
PSW Register  
xxD8  
xxD9  
xxDA  
xxDB  
xxDC  
Port C Data Register  
Port C Configuration Register  
Port C Input Pins (Read Only)  
Reserved for Port C  
Port D  
xxEF  
xxF0 to FB  
xxFC  
On-Chip RAM Mapped as Registers  
X Register  
xxFD  
SP Register  
xxFE  
B Register  
xxDD to xxDF Reserved for Port D  
xxFF  
S Register  
xxE0 to xxE5  
xxE6  
Reserved for EE Control Registers  
0100–017F  
0200–027F  
On-Chip 128 RAM Bytes  
Timer T1 Autoload Register T1RB Lower  
Byte  
On-Chip 128 RAM Bytes (Reads as  
undefined data on COP8SGE)  
xxE7  
Timer T1 Autoload Register T1RB Upper  
Byte  
0300–037F  
On-Chip 128 RAM Bytes (Reads as  
undefined data on COP8SGE)  
xxE8  
xxE9  
xxEA  
xxEB  
ICNTRL Register  
Note: Reading memory locations 0070H–007FH (Segment 0) will return all  
ones. Reading unused memory locations 0080H–00AFH (Segment 0)  
will return undefined data. Reading memory locations from other Seg-  
ments (i.e., Segment 2, Segment 3, … etc.) will return undefined data.  
MICROWIRE/PLUS Shift Register  
Timer T1 Lower Byte  
Timer T1 Upper Byte  
Addressing Modes  
There are ten addressing modes, six for operand addressing  
TRANSFER OF CONTROL ADDRESSING MODES  
Relative  
and four for transfer of control.  
OPERAND ADDRESSING MODES  
Register Indirect  
This mode is used for the JP instruction, with the instruction  
field being added to the program counter to get the new pro-  
gram location. JP has a range from −31 to +32 to allow a  
1-byte relative jump (JP + 1 is implemented by a NOP in-  
struction). There are no “pages” when using JP, since all 15  
bits of PC are used.  
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)  
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 au-  
tomatically post increments or decrements the B or X regis-  
ter after executing the instruction.  
Absolute  
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.  
Direct  
Absolute Long  
The instruction contains an 8-bit address field that directly  
points to the data memory for the operand.  
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 loca-  
tion up to 32k in the program memory space.  
Immediate  
The instruction contains an 8-bit immediate field as the oper-  
and.  
Short Immediate  
Indirect  
This addressing mode is used with the Load B Immediate in-  
struction. The instruction contains a 4-bit immediate field as  
the operand.  
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.  
Note: The VIS is a special case of the Indirect Transfer of Control addressing  
mode, where the double byte vector associated with the interrupt is  
transferred from adjacent addresses in the program memory into the  
program counter (PC) in order to jump to the associated interrupt ser-  
vice routine.  
Indirect  
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.  
www.national.com  
42  
Instruction Set  
Register and Symbol Definition  
Registers  
A
8-Bit Accumulator Register  
8-Bit Address Register  
B
X
8-Bit Address Register  
S
8-Bit Segment Register  
SP  
PC  
PU  
PL  
C
8-Bit Stack Pointer Register  
15-Bit Program Counter Register  
Upper 7 Bits of PC  
Lower 8 Bits of PC  
1 Bit of PSW Register for Carry  
1 Bit of PSW Register for Half Carry  
HC  
GIE  
1 Bit of PSW Register for Global Interrupt  
Enable  
VU  
VL  
Interrupt Vector Upper Byte  
Interrupt Vector Lower Byte  
Symbols  
[B]  
Memory Indirectly Addressed by B Register  
Memory Indirectly Addressed by X Register  
Direct Addressed Memory  
[X]  
MD  
Mem  
Meml  
Direct Addressed Memory or [B]  
Direct Addressed Memory or [B] or  
Immediate Data  
Imm  
Reg  
8-Bit Immediate Data  
Register Memory: Addresses F0 to FF  
(Includes B, X and SP)  
Bit  
Bit Number (0 to 7)  
Loaded with  
Exchanged with  
43  
www.national.com  
Instruction Set (Continued)  
INSTRUCTION SET  
ADD  
ADC  
A,Meml  
A,Meml  
ADD  
A
A
A + Meml  
A + Meml + C, C Carry  
ADD with Carry  
HC Half Carry  
← ←  
A − MemI + C, C Carry  
SUBC  
A,Meml  
Subtract with Carry  
A
HC Half Carry  
AND  
ANDSZ  
OR  
A,Meml  
A,Imm  
A,Meml  
A,Meml  
MD,Imm  
A,Meml  
A,Meml  
A,Meml  
#
Logical AND  
A
A and Meml  
Logical AND Immed., Skip if Zero  
Logical OR  
Skip next if (A and Imm) = 0  
A
A
A or Meml  
XOR  
IFEQ  
IFEQ  
IFNE  
IFGT  
IFBNE  
DRSZ  
SBIT  
RBIT  
IFBIT  
RPND  
X
Logical EXclusive OR  
IF EQual  
A xor Meml  
Compare MD and Imm, Do next if MD = Imm  
Compare A and Meml, Do next if A = Meml  
IF EQual  
Compare A and Meml, Do next if A Meml  
IF Not Equal  
>
IF Greater Than  
Compare A and Meml, Do next if A Meml  
If B Not Equal  
Do next if lower 4 bits of B Imm  
Reg  
Decrement Reg., Skip if Zero  
Set BIT  
Reg Reg − 1, Skip if Reg = 0  
#
#
#
,Mem  
,Mem  
,Mem  
1 to bit, Mem (bit = 0 to 7 immediate)  
0 to bit, Mem  
Reset BIT  
IF BIT  
If bit in A or Mem is true do next instruction  
Reset Software Interrupt Pending Flag  
Reset PeNDing Flag  
EXchange A with Memory  
EXchange A with Memory [X]  
LoaD A with Memory  
LoaD A with Memory [X]  
LoaD B with Immed.  
LoaD Memory Immed  
LoaD Register Memory Immed.  
EXchange A with Memory [B]  
EXchange A with Memory [X]  
LoaD A with Memory [B]  
LoaD A with Memory [X]  
LoaD Memory [B] Immed.  
CLeaR A  
A,Mem  
A,[X]  
A
A
A
A
B
Mem  
[X]  
X
LD  
A,Meml  
A,[X]  
Meml  
[X]  
LD  
LD  
B,Imm  
Imm  
Mem Imm  
LD  
Mem,Imm  
Reg,Imm  
Reg Imm  
LD  
±
±
±
±
X
A, [B  
A, [X  
]
]
A
A
A
A
[B], (B  
[X], (X  
B
X
B
1)  
1)  
1)  
X
±
±
LD  
A, [B ]  
[B], (B  
±
±
LD  
A, [X ]  
[X], (X X 1)  
±
±
LD  
[B ],Imm  
[B] Imm, (B B 1)  
CLR  
INC  
A
A
A
A
A
A
A
A
C
C
0
INCrement A  
A + 1  
DEC  
LAID  
DCOR  
RRC  
RLC  
SWAP  
SC  
DECrement A  
A − 1  
Load A InDirect from ROM  
Decimal CORrect A  
Rotate A Right thru C  
Rotate A Left thru C  
SWAP nibbles of A  
Set C  
ROM (PU,A)  
A
A
A
A
BCD correction of A (follows ADC, SUBC)  
A7  
A7  
A0  
A0  
C
C
A7…A4 A3…A0  
C
C
1, HC  
0, HC  
1
0
RC  
Reset C  
IFC  
IF C  
IF C is true, do next instruction  
IFNC  
POP  
PUSH  
VIS  
IF Not C  
If C is not true, do next instruction  
← ←  
SP SP + 1, A [SP]  
A
A
POP the stack into A  
PUSH A onto the stack  
Vector to Interrupt Service Routine  
Jump absolute Long  
Jump absolute  
[SP] A, SP SP − 1  
PU [VU], PL [VL]  
PC ii (ii = 15 bits, 0 to 32k)  
JMPL  
JMP  
JP  
Addr.  
Addr.  
Disp.  
PC9…0 i (i = 12 bits)  
PC PC + r (r is −31 to +32, except 1)  
Jump relative short  
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44  
Instruction Set (Continued)  
INSTRUCTION SET (Continued)  
← ← ←  
[SP] PL, [SP−1] PU,SP−2, PC ii  
JSRL  
JSR  
Addr.  
Addr  
Jump SubRoutine Long  
Jump SubRoutine  
Jump InDirect  
[SP] PL, [SP−1] PU,SP−2, PC9…0  
i
PL ROM (PU,A)  
JID  
← ←  
SP + 2, PL [SP], PU [SP−1]  
RET  
RETurn from subroutine  
RETurn and SKip  
RETSK  
SP + 2, PL [SP],PU [SP−1],  
skip next instruction  
RETI  
INTR  
NOP  
RETurn from Interrupt  
Generate an Interrupt  
No OPeration  
SP + 2, PL [SP],PU [SP−1],GIE  
1
[SP] PL, [SP−1] PU, SP−2, PC 0FF  
PC PC + 1  
45  
www.national.com  
Instructions Using A & C  
Instruction Execution Time  
CLRA  
INCA  
DECA  
LAID  
1/1  
1/1  
1/1  
1/3  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/3  
1/3  
2/2  
Most 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.  
DCOR  
RRCA  
RLCA  
SWAPA  
SC  
Bytes and Cycles per Instruction  
The following table shows the number of bytes and cycles for  
each instruction in the format of byte/cycle.  
RC  
Arithmetic and Logic Instructions  
IFC  
[B]  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
1/1  
Direct  
3/4  
Immed.  
2/2  
IFNC  
ADD  
ADC  
SUBC  
AND  
OR  
PUSHA  
POPA  
ANDSZ  
3/4  
2/2  
3/4  
2/2  
3/4  
2/2  
3/4  
2/2  
Transfer of Control Instructions  
XOR  
IFEQ  
IFNE  
IFGT  
IFBNE  
DRSZ  
SBIT  
RBIT  
IFBIT  
3/4  
2/2  
JMPL  
JMP  
JP  
3/4  
2/3  
1/3  
3/5  
2/5  
1/3  
1/5  
1/5  
1/5  
1/5  
1/7  
1/1  
3/4  
2/2  
3/4  
2/2  
3/4  
2/2  
JSRL  
JSR  
1/3  
3/4  
3/4  
3/4  
JID  
1/1  
1/1  
1/1  
VIS  
RET  
RETSK  
RETI  
INTR  
NOP  
RPND  
1/1  
Memory Transfer Instructions  
Register  
Indirect  
Direct  
Immed.  
Register Indirect  
Auto Incr. & Decr.  
[B]  
[X]  
1/3  
1/3  
[B+, B−]  
1/2  
[X+, X−]  
1/3  
X A, (Note 14)  
LD A, (Note 14)  
LD B, Imm  
1/1  
1/1  
2/3  
2/3  
2/2  
1/1  
2/2  
1/2  
1/3  
<
(IF B 16)  
>
(IF B 15)  
LD B, Imm  
LD Mem, Imm  
LD Reg, Imm  
IFEQ MD, Imm  
2/2  
3/3  
2/3  
3/3  
2/2  
>
Memory location addressed by B or X or directly.  
Note 14:  
=
www.national.com  
46  
Instruction Execution Time (Continued)  
N i b b l e L o w e r  
47  
www.national.com  
COP8–EVAL-ICUxx: Very Low cost evaluation and de-  
sign test board for COP8ACC and COP8SGx Families,  
from ICU. Real-time environment with add-on A/D, D/A,  
and EEPROM. Includes software routines and reference  
designs.  
Mask Options  
The mask programmable options are shown below. The op-  
tions are programmed at the same time as the ROM pattern  
submission.  
OPTION 1: CLOCK CONFIGURATION  
= 1 Crystal Oscillator (CKI/10)  
G7 (CKO) is clock generator output to crystal/  
resonator with CKI being the clock input  
= 2 Single-pin RC controlled oscillator (CKI/10)  
G7 is available as a HALT restart and/or  
general purpose input  
Manuals, Applications Notes, Literature: Available free  
from our web site at: www.national.com/cop8.  
COP8 Integrated Software/Hardware Design Develop-  
ment Kits  
COP8-EPU: Very Low cost Evaluation & Programming  
Unit. Windows based development and hardware-  
simulation tool for COPSx/xG families, with COP8 device  
programmer and samples. Includes COP8-NSDEV,  
Driveway COP8 Demo, MetaLink Debugger, cables and  
power supply.  
OPTION 2: HALT  
= 1 Enable HALT mode  
COP8-DM: Moderate cost Debug Module from MetaLink.  
A Windows based, real-time in-circuit emulation tool with  
COP8 device programmer. Includes COP8-NSDEV,  
DriveWay COP8 Demo, MetaLink Debugger, power sup-  
ply, emulation cables and adapters.  
= 2 Disable HALT mode  
OPTION 3: BONDING OPTIONS  
= 1 44-Pin PLCC  
= 2 40-Pin DIP  
= 3 N/A  
COP8 Development Languages and Environments  
= 4 28-DIP  
COP8-NSASM: Free COP8 Assembler v5 for Win32.  
Macro assembler, linker, and librarian for COP8 software  
development. Supports all COP8 devices. (DOS/Win16  
v4.10.2 available with limited support). (Compatible with  
WCOP8 IDE, COP8C, and DriveWay COP8).  
= 5 28-Pin SO  
Some device 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 (if clock option=1 has been selected). The  
CKI input frequency is divided down by 10 to produce the in-  
struction cycle clock (1/tc).  
COP8-NSDEV: Very low cost Software Development  
Package for Windows. An integrated development envi-  
ronment for COP8, including WCOP8 IDE, COP8-  
NSASM, COP8-MLSIM.  
Not all packages are available for all devices, please check  
order information.  
COP8C: Moderately priced C Cross-Compiler and Code  
Development System from Byte Craft (no code limit). In-  
cludes BCLIDE (Byte Craft Limited Integrated Develop-  
ment Environment) for Win32, editor, optimizing C Cross-  
Compiler, macro cross assembler, BC-Linker, and  
MetaLink tools support. (DOS/SUN versions available;  
Compiler is installable under WCOP8 IDE; Compatible  
with DriveWay COP8).  
Development Support  
OVERVIEW  
National is engaged with an international community of inde-  
pendent 3rd party vendors who provide hardware and soft-  
ware development tool support. Through National’s interac-  
tion and guidance, these tools cooperate to form a choice of  
tools that fits each developer’s needs.  
EWCOP8-KS: Very Low cost ANSI C-Compiler and Em-  
bedded Workbench from IAR (Kickstart version:  
COP8Sx/Fx only with 2k code limit; No FP). A fully inte-  
grated Win32 IDE, ANSI C-Compiler, macro assembler,  
editor, linker, Liberian, C-Spy simulator/debugger, PLUS  
MetaLink EPU/DM emulator support.  
This section provides a summary of the tool and develop-  
ment kits currently available. Up-to-date information, selec-  
tion guides, free tools, demos, updates, and purchase infor-  
mation can be obtained at our web site at:  
www.national.com/cop8.  
EWCOP8-AS: Moderately priced COP8 Assembler and  
Embedded Workbench from IAR (no code limit). A fully in-  
tegrated Win32 IDE, macro assembler, editor, linker, li-  
brarian, and C-Spy high-level simulator/debugger with  
I/O and interrupts support. (Upgradeable with optional  
C-Compiler and/or MetaLink Debugger/Emulator sup-  
port).  
SUMMARY OF TOOLS  
COP8 Evaluation Tools  
COP8–NSEVAL: Free Software Evaluation package for  
Windows. A fully integrated evaluation environment for  
COP8, including versions of WCOP8 IDE (Integrated De-  
velopment Environment), COP8-NSASM, COP8-MLSIM,  
EWCOP8-BL: Moderately priced ANSI C-Compiler and  
Embedded Workbench from IAR (Baseline version: All  
COP8 devices; 4k code limit; no FP). A fully integrated  
Win32 IDE, ANSI C-Compiler, macro assembler, editor,  
linker, librarian, and C-Spy high-level simulator/debugger.  
(Upgradeable; CWCOP8-M MetaLink tools interface sup-  
port optional).  
COP8C, DriveWay COP8, Manuals, and other COP8  
information.  
COP8–MLSIM: Free Instruction Level Simulator tool for  
Windows. For testing and debugging software instruc-  
tions only (No I/O or interrupt support).  
COP8–EPU: Very Low cost COP8 Evaluation & Pro-  
gramming Unit. Windows based evaluation and  
hardware-simulation tool, with COP8 device programmer  
and erasable samples. Includes COP8-NSDEV, Drive-  
way COP8 Demo, MetaLink Debugger, I/O cables and  
power supply.  
EWCOP8: Full featured ANSI C-Compiler and Embed-  
ded Workbench for Windows from IAR (no code limit). A  
fully integrated Win32 IDE, ANSI C-Compiler, macro as-  
sembler, editor, linker, librarian, and C-Spy high-level  
simulator/debugger. (CWCOP8-M MetaLink tools inter-  
face support optional).  
www.national.com  
48  
COP8 Real-Time Emulation Tools  
Development Support (Continued)  
COP8-DM: MetaLink Debug Module. A moderately  
EWCOP8-M: Full featured ANSI C-Compiler and Embed-  
ded Workbench for Windows from IAR (no code limit). A  
fully integrated Win32 IDE, ANSI C-Compiler, macro as-  
sembler, editor, linker, librarian, C-Spy high-level  
simulator/debugger, PLUS MetaLink debugger/hardware  
interface (CWCOP8-M).  
priced real-time in-circuit emulation tool, with COP8 de-  
vice programmer. Includes MetaLink Debugger, power  
supply, emulation cables and adapters.  
IM-COP8: MetaLink iceMASTER®. A full featured, real-  
time in-circuit emulator for COP8 devices. Includes  
COP8-NSDEV, Driveway COP8 Demo, MetaLink Win-  
dows Debugger, and power supply. Package-specific  
probes and surface mount adaptors are ordered sepa-  
rately.  
COP8 Productivity Enhancement Tools  
WCOP8 IDE: Very Low cost IDE (Integrated Develop-  
ment Environment) from KKD. Supports COP8C, COP8-  
NSASM, COP8-MLSIM, DriveWay COP8, and MetaLink  
debugger under a common Windows Project Manage-  
ment environment. Code development, debug, and emu-  
lation tools can be launched from the project window  
framework.  
COP8 Device Programmer Support  
MetaLink’s EPU and Debug Module include development  
device programming capability for COP8 devices.  
Third-party programmers and automatic handling equip-  
ment cover needs from engineering prototype and pilot  
production, to full production environments.  
DriveWay-COP8: Low cost COP8 Peripherals Code  
Generation tool from Aisys Corporation. Automatically  
generates tested and documented C or Assembly source  
code modules containing I/O drivers and interrupt han-  
dlers for each on-chip peripheral. Application specific  
code can be inserted for customization using the inte-  
grated editor. (Compatible with COP8-NSASM, COP8C,  
and WCOP8 IDE.)  
Factory programming available for high-volume require-  
ments.  
TOOLS ORDERING NUMBERS FOR THE COP888xG/CS  
FAMILY DEVICES  
The COP888xG/CS devices are compatible with the  
COP8SGx devices, and the SGx tools can be also used for  
development.  
COP8-UTILS: Free set of COP8 assembly code ex-  
amples, device drivers, and utilities to speed up code de-  
velopment.  
COP8-MLSIM: Free Instruction Level Simulator tool for  
Windows. For testing and debugging software instruc-  
tions only (No I/O or interrupt support).  
Vendor  
Tools  
Order Number  
COP8-NSEVAL  
Cost  
Notes  
National COP8-NSEVAL  
COP8-NSASM  
Free Web site download  
COP8-NSASM  
Free Included in EPU and DM. Web site download  
Free Included in EPU and DM. Web site download  
COP8-MLSIM  
COP8-MLSIM  
COP8-NSDEV  
COP8-NSDEV  
VL  
VL  
Included in EPU and DM. Order CD from website  
COP8-EPU  
COP8SG-EPU (-1 or -2)  
-1 = 110V, -2 = 220V; Included p/s, 40 pin DIP target  
cable, manuals, software, 16/20/28/40 DIP OTP  
programming socket; add DM target adapter or OTP  
adapter (if needed)  
COP8-DM  
COP8SG-DM (10 MHz)  
M
Included p/s, 28/40/44 pin DIP/SO/PLCC target  
cables, manuals, software, 16/20/28/40 DIP/SO and  
44 PLCC programming socket; add OTP adapter or  
target adapter (if needed)  
DM Target  
Adapters  
DM-COP8/28D-SO  
DM-COP8/44P-44Q  
VL  
L
28 pin DIP to SO converter  
44 pin PLCC to 44 QFP converter  
8k or 32k Eraseable or OTP devices  
Development  
Devices  
COP8FGx7 (15 MHz)  
COP8SGx7 (10 MHz)  
VL  
OTP  
Programming  
Adapters  
COP8SA-PGMA  
COP8-PGMA-44QFP  
COP8-PGMA-28SO  
Call MetaLink  
L
For programming 28 SOIC and 44 PLCC on the EPU  
For programming 44 QFP on any programmer  
L
VL  
For programming 16/20/28 SOIC on any programmer  
IM-COP8  
49  
www.national.com  
Development Support (Continued)  
MetaLink COP8-EPU  
EPU-8SGx (-1 or -2)  
VL  
M
1 = 110V, 2 = 220V; included p/s, 40 pin DIP target  
cable, manuals, software, 16/20/28/40 DIP OTP  
programming socket; add DM target adapter or OTP  
adapter (if needed)  
COP8-DM  
DM4-COP8-888xG (x = C,  
E, G, H, K) or  
Included p/s (PS-10), target cable of choice (DIP or  
PLCC; i.e. DM-COP8/28D), 16/20/28/40 DIP/SO and  
44 PLCC programming sockets. Add OTP adapter (if  
needed) and target adapter (if needed)  
DM5-COP8-FGx (15  
MHz) or DM4-COP8-SGx  
(10 MHz), plus PS-10,  
plus DM-COP8/xxx (ie.  
28D)  
DM Target  
Adapters  
MHW-CNVxx (xx = 33, 34  
etc.)  
L
L
DM target converters for  
16DIP/20SO/28SO/44QFP/28CSP; (i.e. MHW-CNV38  
for 20 pin DIP to SO package converter)  
OTP  
Programming  
Adapters  
MHW-COP8-PGMA-DS  
For programming 16/20/28 SOIC and 44 PLCC on the  
EPU  
MHW-COP8-PGMA-44QFP  
MHW-COP8-PGMA-28CSP  
L
L
For programming 44 QFP on any programmer  
For programming 28 CSP on any programmer  
IM-COP8  
IM-COP8-AD-464 (-220)  
(10 MHz maximum)  
H
Base unit 10 MHz; -220 = 220V; add probe card  
(required) and target adapter (if needed); included  
software and manuals  
IM Probe Card  
PC-8884xG28DW-AD-10  
(x = C, E, G, K)  
M
M
M
L
10 MHz 28 DIP probe card; 2.5V to 6.0V  
10 MHz 40 DIP probe card; 2.5V to 6.0V  
10 MHz 44 PLCC probe card; 2.5V to 6.0V  
16 or 20 or 28 pin SOIC adapter for probe card  
PC-888xG40DW-AD-10  
(x = C, E, G, K)  
PC-888xG44PW-AD-10  
(x = C, E, G, K)  
IM Probe Target  
Adapters  
MHW-SOICxx (xx = 16,  
20, 28)  
MHW-CONV33  
L
44 pin QFP adapter for 44 PLCC probe card  
No power supply  
COP8-EVAL-ICUxx ICU-303  
L
ICU or  
National  
COP8-EVAL-ICUSG  
WCOP8-IDE  
L
No power supply  
KKD  
IAR  
WCOP8-IDE  
EWCOP8-xx  
COP8C  
VL  
Included in EPU and DM  
See summary above  
COP8C  
L - H Included all software and manuals  
Byte  
Craft  
M
Included all software and manuals  
Aisys  
DriveWay COP8  
DriveWay COP8  
Contact vendors  
L
Included all software and manuals  
OTP Programmers  
L - H For approved programmer listings and vendor  
inforamtion go to our OTP support page at:  
www.national.com/cop8  
<
Cost: Free; VL = $100; L = $100 - $300; M = $300 - $1k; H = $1k - $3k; VH = $3k - $5k  
www.national.com  
50  
Development Support (Continued)  
WHERE TO GET TOOLS  
Tools are ordered directly from the following vendors. Please go to the vendor’s web site for current listings of distributors.  
Vendor  
Home Office  
U.S.A.: Santa Clara, CA  
1-408-327-8820  
Electronic Sites  
Other Main Offices  
Distributors  
Aisys  
www.aisysinc.com  
@
info aisysinc.com  
fax: 1-408-327-8830  
U.S.A.  
Byte Craft  
IAR  
www.bytecraft.com  
Distributors  
@
1-519-888-6911  
info bytecraft.com  
fax: 1-519-746-6751  
Sweden: Uppsala  
+46 18 16 78 00  
fax: +46 18 16 78 38  
www.iar.se  
U.S.A.: San Francisco  
1-415-765-5500  
@
info iar.se  
@
info iar.com  
fax: 1-415-765-5503  
U.K.: London  
@
info iarsys.co.uk  
@
info iar.de  
+44 171 924 33 34  
fax: +44 171 924 53 41  
Germany: Munich  
+49 89 470 6022  
fax: +49 89 470 956  
Switzeland: Hoehe  
+41 34 497 28 20  
fax: +41 34 497 28 21  
ICU  
Sweden: Polygonvaegen  
+46 8 630 11 20  
www.icu.se  
@
support icu.se  
@
fax: +46 8 630 11 70  
Denmark:  
support icu.ch  
KKD  
www.kkd.dk  
MetaLink  
U.S.A.: Chandler, AZ  
1-800-638-2423  
www.metaice.com  
Germany: Kirchseeon  
80-91-5696-0  
@
sales metaice.com  
@
fax: 1-602-926-1198  
support metaice.com  
fax: 80-91-2386  
@
bbs: 1-602-962-0013  
www.metalink.de  
islanger metalink.de  
Distributors Worldwide  
National  
U.S.A.: Santa Clara, CA  
1-800-272-9959  
www.national.com/cop8  
Europe: +49 (0) 180 530 8585  
fax: +49 (0) 180 530 8586  
Distributors Worldwide  
@
support nsc.com  
@
fax: 1-800-737-7018  
europe.support nsc.com  
The following companies have approved COP8 program-  
mers in a variety of configurations. Contact your local office  
or distributor. You can link to their web sites and get the lat-  
est listing of approved programmers from National’s COP8  
OTP Support page at: www.national.com/cop8.  
CUSTOMER SUPPORT  
Complete product information and technical support is avail-  
able from National’s customer response centers, and from  
our on-line COP8 customer support sites.  
Advantech; Advin; BP Microsystems; Data I/O; Hi-Lo Sys-  
tems; ICE Technology; Lloyd Research; Logical Devices;  
MQP; Needhams; Phyton; SMS; Stag Programmers; Sys-  
tem General; Tribal Microsystems; Xeltek.  
51  
www.national.com  
Physical Dimensions inches (millimeters) unless otherwise noted  
Molded Dual-In-Line Package (N)  
Order Number COP688KG-XXX/N, COP888KG-XXX/N  
NS Package Number N40A  
Plastic Leaded Chip Carrier (V)  
Order Number COP688KG-XXXV, COP888KG-XXX/V  
NS Package Number V44A  
www.national.com  
52  
Notes  
LIFE SUPPORT POLICY  
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT  
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL  
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:  
1. Life support devices or systems are devices or  
systems which, (a) are intended for surgical implant  
into the body, or (b) support or sustain life, and  
whose failure to perform when properly used in  
accordance with instructions for use provided in the  
labeling, can be reasonably expected to result in a  
significant injury to the user.  
2. A critical component is any component of a life  
support device or system whose failure to perform  
can be reasonably expected to cause the failure of  
the life support device or system, or to affect its  
safety or effectiveness.  
National Semiconductor  
Corporation  
Americas  
Tel: 1-800-272-9959  
Fax: 1-800-737-7018  
Email: support@nsc.com  
National Semiconductor  
Europe  
National Semiconductor  
Asia Pacific Customer  
Response Group  
Tel: 65-2544466  
Fax: 65-2504466  
National Semiconductor  
Japan Ltd.  
Tel: 81-3-5639-7560  
Fax: 81-3-5639-7507  
Fax: +49 (0) 180-530 85 86  
Email: europe.support@nsc.com  
Deutsch Tel: +49 (0) 69 9508 6208  
English Tel: +44 (0) 870 24 0 2171  
Français Tel: +33 (0) 1 41 91 8790  
Email: ap.support@nsc.com  
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.  
IMPORTANT NOTICE  
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,  
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should  
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are  
sold subject to TIs terms and conditions of sale supplied at the time of order acknowledgment.  
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TIs standard  
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where  
mandated by government requirements, testing of all parameters of each product is not necessarily performed.  
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and  
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide  
adequate design and operating safeguards.  
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,  
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information  
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a  
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual  
property of the third party, or a license from TI under the patents or other intellectual property of TI.  
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied  
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive  
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional  
restrictions.  
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all  
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not  
responsible or liable for any such statements.  
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably  
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing  
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and  
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products  
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be  
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in  
such safety-critical applications.  
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are  
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military  
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at  
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.  
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are  
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated  
products in automotive applications, TI will not be responsible for any failure to meet such requirements.  
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:  
Products  
Audio  
Applications  
www.ti.com/audio  
amplifier.ti.com  
dataconverter.ti.com  
www.dlp.com  
Communications and Telecom www.ti.com/communications  
Amplifiers  
Data Converters  
DLP® Products  
DSP  
Computers and Peripherals  
Consumer Electronics  
Energy and Lighting  
Industrial  
www.ti.com/computers  
www.ti.com/consumer-apps  
www.ti.com/energy  
dsp.ti.com  
www.ti.com/industrial  
www.ti.com/medical  
www.ti.com/security  
Clocks and Timers  
Interface  
www.ti.com/clocks  
interface.ti.com  
logic.ti.com  
Medical  
Security  
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