3886GROUP View Datasheet(PDF) - MITSUBISHI ELECTRIC

Part Name

Description

Manufacturer

3886GROUP

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI ELECTRIC  

MITSUBISHI MICROCOMPUTERS

3886 Group

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

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

register are automatically pushed onto the stack.

2. The interrupt disable flag is set and the corresponding interrupt

request bit is cleared.

3. The interrupt jump destination address is read from the vector

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 003916).

1. INT0 or Input buffer full

2. INT1 or Output buffer empty

3. Serial I/O1 transmission or SCLSDA

4. CNTR0 or SCLSDA

5. Serial I/O2 or I2C

6. INT2 or I2C

7. CNTR1 or Key-on wake-up

8. A-D conversion or Key-on wake-up

External Interrupt Pin Selection

The occurrence sources of the external interrupt INT2, INT3, and

INT4 can be selected from either input from INT20, INT30, INT40

pin, or input from INT21, INT31, INT41 pin by the INT2, INT3, INT4

interrupt switch bit (bit 4 of address 002F16).

s Notes

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 003A16)

• Interrupt source selection register (address 003916)

• INT2, INT3, INT4 interrupt switch bit of Port control register 2 (bit

4 of address 002F16)

Accept the interrupt after clearing the interrupt request bit to “0”

after interrupt is disabled and the above register or bit is set.

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