Datasheet
170
ATmega640/1280/1281/2560/2561
2549K–AVR–01/07
TIFR1 – Timer/Counter1
Interrupt Flag Register
TIFR3 – Timer/Counter3
Interrupt Flag Register
TIFR4 – Timer/Counter4
Interrupt Flag Register
TIFR5 – Timer/Counter5
Interrupt Flag Register
• Bit 5 – ICFn: Timer/Countern, Input Capture Flag
This flag is set when a capture event occurs on the ICPn pin. When the Input Capture
Register (ICRn) is set by the WGMn3:0 to be used as the TOP value, the ICFn Flag is
set when the counter reaches the TOP value.
ICFn is automatically cleared when the Input Capture Interrupt Vector is executed. Alter-
natively, ICFn can be cleared by writing a logic one to its bit location.
• Bit 3– OCFnC: Timer/Countern, Output Compare C Match Flag
This flag is set in the timer clock cycle after the counter (TCNTn) value matches the Out-
put Compare Register C (OCRnC).
Note that a Forced Output Compare (FOCnC) strobe will not set the OCFnC Flag.
OCFnC is automatically cleared when the Output Compare Match C Interrupt Vector is
executed. Alternatively, OCFnC can be cleared by writing a logic one to its bit location.
• Bit 2 – OCFnB: Timer/Counter1, Output Compare B Match Flag
This flag is set in the timer clock cycle after the counter (TCNTn) value matches the Out-
put Compare Register B (OCRnB).
Note that a Forced Output Compare (FOCnB) strobe will not set the OCFnB Flag.
OCFnB is automatically cleared when the Output Compare Match B Interrupt Vector is
executed. Alternatively, OCFnB 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 (TCNTn value matches the Out-
put Compare Register A (OCRnA).
Note that a Forced Output Compare (FOCnA) strobe will not set the OCFnA Flag.
Bit 76543210
0x16 (0x36)
– –ICF1– OCF1C OCF1B OCF1A TOV1 TIFR1
Read/Write R R R/W RR/W R/W R/W R/W
Initial Value00000000
Bit 76543210
0x18 (0x38)
– –ICF3– OCF3C OCF3B OCF3A TOV3 TIFR3
Read/Write R R R/W RR/W R/W R/W R/W
Initial Value00000000
Bit 76543210
0x19 (0x39)
– –ICF4– OCF4C OCF4B OCF4A TOV4 TIFR4
Read/Write R R R/W RR/W R/W R/W R/W
Initial Value00000000
Bit 76543210
0x1A (0x3A)
– –ICF5– OCF5C OCF5B OCF5A TOV5 TIFR5
Read/Write R R R/W RR/W R/W R/W R/W
Initial Value00000000