73
Atmel ATmega16/32/64/M1/C1 [DATASHEET]
7647K–AVR–12/13
10.2.4 Pin Change Interrupt Flag Register - PCIFR
Bit 7..4 - Res: Reserved Bits
These bits are unused bits in the ATmega16/32/64/M1/C1, and will always read as zero.
Bit 3 - PCIF3: Pin Change Interrupt Flag 3
When a logic change on any PCINT26..24 pin triggers an interrupt request, PCIF3 becomes set (one). If the I-bit in SREG and
the PCIE3 bit in PCICR are set (one), the MCU will jump to the corresponding interrupt vector. The flag is cleared when the
interrupt routine is executed. Alternatively, 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 PCICR are set (one), the MCU will jump to the corresponding Interrupt vector. The flag is cleared when the
interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.
Bit 1 - PCIF1: Pin Change Interrupt Flag 1
When a logic change on any PCINT15..8 pin triggers an interrupt request, PCIF1 becomes set (one). If the I-bit in SREG and
the PCIE1 bit in PCICR are set (one), the MCU will jump to the corresponding Interrupt vector. The flag is cleared when the
interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.
Bit 0 - PCIF0: Pin Change Interrupt Flag 0
When a logic change on any PCINT7..0 pin triggers an interrupt request, PCIF0 becomes set (one). If the I-bit in SREG and the
PCIE0 bit in PCICR are set (one), the MCU will jump to the corresponding Interrupt vector. The flag is cleared when the interrupt
routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.
10.2.5 Pin Change Mask Register 3 – PCMSK3
Bit 7..3 – Res: Reserved Bit
These bits are unused bits in the ATmega16/32/64/M1/C1, and will always read as zero.
Bit 2..0 – PCINT26..24: Pin Change Enable Mask 26..24
Each PCINT26..24-bit selects whether pin change interrupt is enabled on the corresponding I/O pin. If PCINT26..24 is set and
the PCIE3 bit in PCICR is set, pin change interrupt is enabled on the corresponding I/O pin. If PCINT23..24 is cleared, pin
change interrupt on the corresponding I/O pin is disabled.
10.2.6 Pin Change Mask Register 2 – PCMSK2
Bit 7..0 – PCINT23..16: Pin Change Enable Mask 23..16
Each PCINT23..16-bit selects whether pin change interrupt is enabled on the corresponding I/O pin. If PCINT23..16 is set and
the PCIE2 bit in PCICR is set, pin change interrupt is enabled on the corresponding I/O pin. If PCINT23..16 is cleared, pin
change interrupt on the corresponding I/O pin is disabled.
Bit
7
65
43
21
0
–
PCIF3
PCIF2
PCIF1
PCIF0
PCIFR
Read/Write
R
R/W
Initial Value
0
00
0
Bit
7
6
543
2
1
0
-
PCINT26
PCINT25
PCINT24
PCMSK3
Read/Write
R/W
Initial Value
0
Bit
765
432
1
0
PCINT23 PCINT22 PCINT21 PCINT20 PCINT19 PCINT18
PCINT17
PCINT16
PCMSK2
Read/Write
R/W
Initial Value
000
0