141
8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
The Input Capture Register is 16-bit in size. To ensure that both the high and low bytes are read
simultaneously when the CPU accesses these registers, the access is performed using an 8-bit
temporary High Byte Register (TEMP). This temporary register is shared by all the other 16-bit
registers. See
”Accessing 16-bit Registers” on page 117
.
16.11.8
TIMSK1 – Timer/Counter1 Interrupt Mask Register
• Bit 7, 6 – Reserved
These bits are unused bits in the ATmega48A/PA/88A/PA/168A/PA/328/P, and will always read
as zero.
• Bit 5 – ICIE1: Timer/Counter1, Input Capture Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Input Capture interrupt is enabled. The corresponding Interrupt
Vector (see “Interrupts” on page 59) is executed when the ICF1 Flag, located in TIFR1, is set.
• Bit 4, 3 – Reserved
These bits are unused bits in the ATmega48A/PA/88A/PA/168A/PA/328/P, and will always read
as zero.
• Bit 2 – OCIE1B: Timer/Counter1, Output Compare B Match Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Output Compare B Match interrupt is enabled. The corresponding
Interrupt Vector (see “Interrupts” on page 59) is executed when the OCF1B Flag, located in
TIFR1, is set.
• Bit 1 – OCIE1A: Timer/Counter1, Output Compare A Match Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Output Compare A Match interrupt is enabled. The corresponding
Interrupt Vector (see “Interrupts” on page 59) is executed when the OCF1A Flag, located in
TIFR1, is set.
• Bit 0 – TOIE1: Timer/Counter1, Overflow Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Overflow interrupt is enabled. The corresponding Interrupt Vector
(See
) is executed when the TOV1 Flag, located in TIFR1, is set.
16.11.9
TIFR1 – Timer/Counter1 Interrupt Flag Register
• Bit 7, 6 – Reserved
These bits are unused bits in the ATmega48A/PA/88A/PA/168A/PA/328/P, and will always read
as zero.
Bit
7
6
5
4
3
2
1
0
–
–
ICIE1
–
–
OCIE1B
OCIE1A
TOIE1
TIMSK1
Read/Write
R
R
R/W
R
R
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
–
–
ICF1
–
–
OCF1B
OCF1A
TOV1
TIFR1
Read/Write
R
R
R/W
R
R
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0