Datasheet

8011O–AVR–07/10

ATmega164P/324P/644P

10.2.4 PCICR – Pin Change Interrupt Control Register

• Bit 3 – 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 PCINT31..24 pin will cause an inter-

rupt. The corresponding interrupt of Pin Change Interrupt Request is executed from the PCI3

Interrupt Vector. PCINT31..24 pins are enabled individually by the PCMSK3 Register.

• Bit 2 – 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 PCI2

Interrupt Vector. PCINT23..16 pins are enabled individually by the PCMSK2 Register.

• Bit 1 – 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 PCI1

Interrupt Vector. PCINT15..8 pins are enabled individually by the PCMSK1 Register.

• Bit 0 – 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 PCI0 Interrupt

Vector. PCINT7..0 pins are enabled individually by the PCMSK0 Register.

10.2.5 PCIFR – Pin Change Interrupt Flag Register

• Bit 3– PCIF3: Pin Change Interrupt Flag 3

When a logic change on any PCINT31..24 pin triggers an interrupt request, PCIF3 becomes set

(one). If the I-bit in SREG and the PCIE3 bit in EIMSK are set (one), the MCU will jump to the

corresponding Interrupt Vector. The flag is cleared when the interrupt routine is executed. Alter-

natively, the flag can be cleared by writing a logical one to it.

• Bit 2 – PCIF2: Pin Change Interrupt Flag 2

When a logic change on any PCINT23..16 pin triggers an interrupt request, PCIF2 becomes set

(one). If the I-bit in SREG and the PCIE2 bit in EIMSK are set (one), the MCU will jump to the

corresponding Interrupt Vector. The flag is cleared when the interrupt routine is executed. Alter-

natively, the flag can be cleared by writing a logical one to it.

Bit 76543210

(0x68)

– – – – PCIE3 PCIE2 PCIE1 PCIE0 PCICR

Read/Write RRRRR/WR/WR/WR/W

Initial Value00000000

Bit 76543210

0x1B (0x3B)

– – PCIF3 PCIF2 PCIF1 PCIF0 PCIFR

Read/Write RRRRR/WR/WR/WR/W

Initial Value00000000