
MB89630 SERIES HARDWARE MANUAL
2-86
(3) Description of registers
(a) External-interrupt 1 control register 1 (EIC1)
The EIC1 controls interrupts by the INT0 and INT1 pins.
Note: The bit manipulation instructions (Read Modify instructions) should not be used for this register.
[Bit 7] EIR1: External-interrupt request flag
When the edge specified by the SEL1 bit is input to the INT1 pin, bit 7 is set to 1. When the EIE1 bit is
1, an interrupt request (IRQ0) is output if this bit is set.
The meaning of each bit to be read is as follows:
1 is always read when the Read Modify Write instruction is read.
The meaning of each bit to be written is as follows:
[Bit 5] SEL1: Edge-polarity select bit
Bit 5 is used to control the input edge polarity of the INT1 pin.
[Bit 4] EIE1: Interrupt-enable bit
Bit 4 is used to enable an external-interrupt request by the INT1 pin.
[Bit 3] EIR0: External-interrupt request flag
When the edge specified by the SEL0 bit is input to the INT0 pin, bit 3 is set to 1. When the EIE0 is 1,
an interrupt request (IRQ0) is output if this bit is set.
The meaning of each bit to be read is as follows:
1 is always read when the Read Modify Write instruction is read.