Datasheet

139
7728G–AVR–06/10
ATtiny87/ATtiny167
12.11.10 Timer/Counter1 Interrupt Flag Register – TIFR1
• Bit 7..6 – Reserved Bits
These bits are reserved for future use.
• Bit 5 – ICF1: 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. Alterna-
tively, ICF1 can be cleared by writing a logic one to its bit location.
• Bit 4..3 – Reserved Bits
These bits are reserved for future use.
• Bit 2 – OCF1B: 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: 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/Counter Overflow Flag
The setting of this flag is dependent of the WGM13:0 bits setting. In Normal and CTC modes,
the TOV1 flag is set when the timer overflows. Refer to Table 12-4 on page 134 for the TOV1
flag behavior when using another WGM13:0 bit setting.
TOV1 is automatically cleared when the Timer/Counter1 Overflow Interrupt Vector is exe-
cuted. Alternatively, TOV1 can be cleared by writing a logic one to its bit location.
Bit 76543210
– – ICF1 – – OCF1B OCF1A TOV1 TIFR1
Read/Write R R R/W R R R/W R/W R/W
Initial Value00000000