Datasheet

112
8183F–AVR–06/12
ATtiny24A/44A/84A
12.11.9 TIFR1 – Timer/Counter Interrupt Flag Register 1
• Bits 7:6 – Res: Reserved Bits
These bits are reserved bits in the ATtiny24A/44A/84A 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 WGM1[3:0] 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.
• Bits 4:3 – Res: Reserved Bits
These bits are reserved bits in the ATtiny24A/44A/84A 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 (1B) 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 (1A) 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 WGM1[3:0] bits setting. In Normal and CTC modes,
the TOV1 flag is set when the timer overflows. See Table 12-5 on page 108 for the TOV1 flag
behavior when using another WGM1[3:0] 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.
Bit 765432 10
0x0B (0x2B) – – ICF1 – – OCF1B OCF1A TOV1 TIFR1
Read/Write R R R/W R R R/W R/W R/W
Initial Value000000 00