M38867E8AHP MITSUBISHI [Mitsubishi Electric Semiconductor], M38867E8AHP Datasheet - Page 19

• Manufacturer Part Number: M38867E8AHP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER??
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

INTERRUPTS
Interrupts occur by 16 sources among 21 sources: nine external,
eleven internal, and one software.
Interrupt Control
Each interrupt is controlled by an interrupt request bit, an interrupt
enable bit, and the interrupt disable flag except for the software in-
terrupt set by the BRK instruction. An interrupt occurs if the
corresponding interrupt request and enable bits are “1” and the in-
terrupt disable flag is “0”.
Interrupt enable bits can be set or cleared by software.
Interrupt request bits can be cleared by software, but cannot be
set by software.
The BRK instruction cannot be disabled with any flag or bit. The I
(interrupt disable) flag disables all interrupts except the BRK in-
struction interrupt.
When several interrupts occur at the same time, the interrupts are
received according to priority.
Interrupt Operation
By acceptance of an interrupt, the following operations are auto-
matically performed:
1. The contents of the program counter and the processor status
2. The interrupt disable flag is set and the corresponding interrupt
3. The interrupt jump destination address is read from the vector
register are automatically pushed onto the stack.
request bit is cleared.
table into the program counter.
Interrupt Source Selection
Any of the following interrupt sources can be selected by the inter-
rupt source selection register (address 0039
1. INT
2. INT
3. Serial I/O1 transmission or S
4. CNTR
5. Serial I/O2 or I
6. INT
7. CNTR
8. A-D conversion or Key-on wake-up
External Interrupt Pin Selection
The occurrence sources of the external interrupt INT
INT
pin, or input from INT
interrupt switch bit (bit 4 of address 002F
When setting of the following register or bit is changed, the inter-
rupt request bit may be set to “1.”
• Interrupt edge selection register (address 003A
• Interrupt source selection register (address 0039
• INT
Accept the interrupt after clearing the interrupt request bit to “0”
after interrupt is disabled and the above register or bit is set.
4 of address 002F
Notes
4
can be selected from either input from INT
2
0
1
2
, INT
or Input buffer full
or Output buffer empty
or I
0
1
or S
or Key-on wake-up
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
2
3
C
, INT
CL
S
2
4
C
DA
interrupt switch bit of
16
21
MITSUBISHI MICROCOMPUTERS
)
, INT
31
, INT
CL
S
DA
41
pin by the INT
P
16
3886 Group
ort control register 2 (bit
).
16
).
16
20
16
)
, INT
2
)
2
, INT
, INT
30
, INT
3
3
, INT
, and
19
40
4