60
8023F–AVR–07/09
ATmega325P/3250P
12.3.2
EIMSK – External Interrupt Mask Register
Bit 7 – PCIE3: Pin Change Interrupt Enable 3
When the PCIE3 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin
change interrupt 3 is enabled. Any change on any enabled PCINT30:24 pin will cause an inter-
rupt. The corresponding interrupt of Pin Change Interrupt Request is executed from the PCINT3
Interrupt Vector. PCINT30:24 pins are enabled individually by the PCMSK3 Register.
This bit is reserved bit in ATmega325P and should always be written to zero.
Bit 6 – PCIE2: Pin Change Interrupt Enable 2
When the PCIE2 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin
change interrupt 2 is enabled. Any change on any enabled PCINT23:16 pin will cause an inter-
rupt. The corresponding interrupt of Pin Change Interrupt Request is executed from the PCINT2
Interrupt Vector. PCINT23:16 pins are enabled individually by the PCMSK2 Register.
This bit is reserved bit in ATmega325P and should always be written to zero.
Bit 5 – PCIE1: Pin Change Interrupt Enable 1
When the PCIE1 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin
change interrupt 1 is enabled. Any change on any enabled PCINT15:8 pin will cause an inter-
rupt. The corresponding interrupt of Pin Change Interrupt Request is executed from the PCINT1
Interrupt Vector. PCINT15:8 pins are enabled individually by the PCMSK1 Register.
Bit 4 – PCIE0: Pin Change Interrupt Enable 0
When the PCIE0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin
change interrupt 0 is enabled. Any change on any enabled PCINT7:0 pin will cause an interrupt.
The corresponding interrupt of Pin Change Interrupt Request is executed from the PCINT0 Inter-
rupt Vector. PCINT7:0 pins are enabled individually by the PCMSK0 Register.
Bit 0 – INT0: External Interrupt Request 0 Enable
When the INT0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the exter-
nal pin interrupt is enabled. The Interrupt Sense Control0 bits 1/0 (ISC01 and ISC00) in the
External Interrupt Control Register A (EICRA) define whether the external interrupt is activated
on rising and/or falling edge of the INT0 pin or level sensed. Activity on the pin will cause an
interrupt request even if INT0 is configured as an output. The corresponding interrupt of External
Interrupt Request 0 is executed from the INT0 Interrupt Vector.
Table 12-1.
Interrupt 0 Sense Control
ISC01
ISC00
Description
0
The low level of INT0 generates an interrupt request.
0
1
Any logical change on INT0 generates an interrupt request.
1
0
The falling edge of INT0 generates an interrupt request.
1
The rising edge of INT0 generates an interrupt request.
Bit
7
6543
210
PCIE3
PCIE2
PCIE1
PCIE0
–
–INT0
EIMSK
Read/Write
R/W
R
R/W
Initial Value
0
0000
000