133
7530J–AVR–03/12
Atmel ATmega48/88/168 Automotive
Bit 4, 3 – Res: Reserved Bits
These bits are unused bits in the ATmega48/88/168, 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
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
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
14.10.9
Timer/Counter1 Interrupt Flag Register – TIFR1
Bit 7, 6 – Res: Reserved Bits
These bits are unused bits in the ATmega48/88/168, and will always read as zero.
Bit 5 – ICF1: Timer/Counter1, Input Capture Flag
This flag is set when a capture event occurs on the ICP1 pin. When the Input Capture Register
(ICR1) is set by the WGM13:0 to be used as the TOP value, the ICF1 Flag is set when the coun-
ter reaches the TOP value.
ICF1 is automatically cleared when the Input Capture Interrupt Vector is executed. Alternatively,
ICF1 can be cleared by writing a logic one to its bit location.
Bit 4, 3 – Res: Reserved Bits
These bits are unused bits in the ATmega48/88/168, and will always read as zero.
Bit 2 – OCF1B: Timer/Counter1, Output Compare B Match Flag
This flag is set in the timer clock cycle after the counter (TCNT1) value matches the Output
Compare Register B (OCR1B).
Note that a Forced Output Compare (FOC1B) strobe will not set the OCF1B Flag.
OCF1B is automatically cleared when the Output Compare Match B Interrupt Vector is exe-
cuted. Alternatively, OCF1B can be cleared by writing a logic one to its bit location.
Bit
76543210
–
ICF1
–
OCF1B
OCF1A
TOV1
TIFR1
Read/Write
R
R/W
R
R/W
Initial Value
00000000