
97
ATmega8A [DATASHEET]
8159E–AVR–02/2013
17.11.7
TIMSK(1) – Timer/Counter Interrupt Mask Register Note:
1. This register contains interrupt control bits for several Timer/Counters, but only Timer1 bits are described in this
section. The remaining bits are described in their respective timer sections.
Bit 5 – TICIE1: 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
44) is executed when the ICF1 Flag, located in TIFR, is set.
Bit 4 – 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 “Inter- Bit 3 – 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 “Inter- Bit 2 – 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
executed when the TOV1 Flag, located in TIFR, is set.
17.11.8
TIFR(1) – Timer/Counter Interrupt Flag Register Note:
1. This register contains flag bits for several Timer/Counters, but only Timer1 bits are described in this section. The
remaining bits are described in their respective timer sections.
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 counter 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 – OCF1A: Timer/Counter1, Output Compare A Match Flag
This flag is set in the timer clock cycle after the counter (TCNT1) value matches the Output Compare Register A
(OCR1A).
Note that a Forced Output Compare (FOC1A) strobe will not set the OCF1A Flag.
Bit
765
43210
OCIE2
TOIE2
TICIE1
OCIE1A
OCIE1B
TOIE1
–
TOIE0
TIMSK
Read/Write
R/W
R
R/W
Initial Value
000
00000
Bit
76543210
OCF2
TOV2
ICF1
OCF1A
OCF1B
TOV1
–
TOV0
TIFR
Read/Write
R/W
R
R/W
Initial Value
00000000