M37212 Mitsubishi, M37212 Datasheet - Page 72

• Manufacturer Part Number: M37212
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
• Manufacturer: Mitsubishi

8.11 SOFTWARE RUNAWAY DETECT FUNCTION
This microcomputer has a function to decode undefined instructions
to detect a software runaway.
When an undefined op-code is input to the CPU as an instruction
code during operation, the following processing is done.
Note, however, that the software runaway detecting function cannot
be invalid.
Fig. 8.11.1 Sequence at Detecting Software Runaway Detection
72
The CPU generates an undefined instruction decoding signal.
The device is internally reset because of occurrence of the unde-
fined instruction decoding signal.
As a result of internal reset, the same reset processing as in the
case of ordinary reset operation is done, and the program restarts
from the reset vector.
A d d r e s s
S Y N C
D a t a
U n d e f i n e d i n s t r u c t i o n d e c o d i n g s i g n a l
o c c u r s . I n t e r n a l r e s e t s i g n a l o c c u r s .
P C
?
M37212M4/M8–XXXSP, M37212M6–XXXSP/FP
?
0 1 , S
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
P C
H
0 1 , S – 1
P C
L
0 1 , S – 2
R e s e t s e q u e n c e
A D
L
P S
, A D
P C
S
?
F F F E
H
: I n v a l i d
: S t a c k p o i n t e r
: J u m p d e s t i n a t i o n a d d r e s s o f r e s e t
: U n d e f i n e d i n s t r u c t i o n d e c o d e
: P r o g r a m c o u n t e r
with ON-SCREEN DISPLAY CONTROLLER
1 6
A D
MITSUBISHI MICROCOMPUTERS
L
F F F F
M37212EFSP/FP
1 6
A D
H
A D
A D
H
L
,
Rev. 1.0