ATmega48/88/168
• 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. Alter-
natively, the flag can be cleared by writing a logical one to it.
11.1.6
Pin Change Mask Register 2 – PCMSK2
Bit
7
6
5
PCINT21
R/W
0
4
PCINT20
R/W
0
3
PCINT19
R/W
0
2
PCINT18
R/W
0
1
PCINT17
R/W
0
0
PCINT16
R/W
0
PCINT23
R/W
0
PCINT22
R/W
0
PCMSK2
Read/Write
Initial Value
• 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.
11.1.7
Pin Change Mask Register 1 – PCMSK1
Bit
7
6
PCINT14
R/W
0
5
PCINT13
R/W
0
4
PCINT12
R/W
0
3
PCINT11
R/W
0
2
PCINT10
R/W
0
1
PCINT9
R/W
0
0
PCINT8
R/W
0
–
R
0
PCMSK1
Read/Write
Initial Value
• Bit 7 – Res: Reserved Bit
This bit is an unused bit in the ATmega48/88/168, and will always read as zero.
• Bit 6..0 – PCINT14..8: Pin Change Enable Mask 14..8
Each PCINT14..8-bit selects whether pin change interrupt is enabled on the corresponding I/O
pin. If PCINT14..8 is set and the PCIE1 bit in PCICR is set, pin change interrupt is enabled on
the corresponding I/O pin. If PCINT14..8 is cleared, pin change interrupt on the corresponding
I/O pin is disabled.
11.1.8
Pin Change Mask Register 0 – PCMSK0
Bit
7
6
5
4
3
2
1
0
PCINT7
R/W
0
PCINT6
R/W
0
PCINT5
R/W
0
PCINT4
R/W
0
PCINT3
R/W
0
PCINT2
R/W
0
PCINT1
R/W
0
PCINT0
R/W
0
PCMSK0
Read/Write
Initial Value
• Bit 7..0 – PCINT7..0: Pin Change Enable Mask 7..0
Each PCINT7..0 bit selects whether pin change interrupt is enabled on the corresponding I/O
pin. If PCINT7..0 is set and the PCIE0 bit in PCICR is set, pin change interrupt is enabled on the
corresponding I/O pin. If PCINT7..0 is cleared, pin change interrupt on the corresponding I/O pin
is disabled.
87
2545E–AVR–02/05
MICROCHIP [ MICROCHIP ]
