
141
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
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
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 – Reserved
These bits are unused 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 1 – 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.
OCF1A is automatically cleared when the Output Compare Match A Interrupt Vector is exe-
cuted. Alternatively, OCF1A can be cleared by writing a logic one to its bit location.
Bit 0 – TOV1: Timer/Counter1, Overflow Flag
The setting of this flag is dependent of the WGMn3:0 bits setting. In Normal and CTC modes,
Flag behavior when using another WGMn3:0 bit setting.
TOV1 is automatically cleared when the Timer/Counter1 Overflow Interrupt Vector is executed.
Alternatively, TOV1 can be cleared by writing a logic one to its bit location.
16.12.15 TIFR3 – Timer/Counter3 Interrupt Flag Register
Bit 7:6 – Reserved
These bits are unused and will always read as zero.
Bit 5 – ICF3: Timer/Counter3, Input Capture Flag
This flag is set when a capture event occurs on the ICP3 pin. When the Input Capture Register
(ICR1) is set by the WGMn3:0 to be used as the TOP value, the ICF3 Flag is set when the coun-
ter reaches the TOP value.
ICF3 is automatically cleared when the Input Capture Interrupt Vector is executed. Alternatively,
ICF3 can be cleared by writing a logic one to its bit location.
Bit
76543210
0x18 (0x38)
–
–ICF3
–
OCF3B
OCF3A
TOV3
TIFR3
Read/Write
R
R/W
R
R/W
Initial Value
00000000