18.9.8 TC0 Interrupt Flag Register
When addressing I/O registers as data space using LD and ST instructions, the provided offset must be used. When using the I/O specific commands IN and OUT, the offset is reduced by 0x20, resulting in an I/O address offset within 0x00 - 0x3F.
The device is a complex microcontroller with more peripheral units than can be supported within the 64 locations reserved in Opcode for the IN and OUT instructions. For the extended I/O space from 0x60 in SRAM, only the ST/STS/STD and LD/LDS/LDD instructions can be used.
| Name: | TIFR0 |
| Offset: | 0x35 |
| Reset: | 0x00 |
| Property: | When addressing as I/O Register: address offset is 0x15 |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| OCF0B | OCF0A | TOV0 | |||||||
| Access | R/W | R/W | R/W | ||||||
| Reset | 0 | 0 | 0 |
Bit 2 – OCF0B Timer/Counter 0, Output Compare B Match Flag
The OCF0B bit is set when a compare match occurs between the Timer/Counter and the data in OCR0B – Output Compare Register0 B. OCF0B is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, OCF0B is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE0B (Timer/Counter Compare B Match Interrupt Enable), and OCF0B are set, the Timer/Counter Compare Match Interrupt is executed.
Bit 1 – OCF0A Timer/Counter 0, Output Compare A Match Flag
The OCF0A bit is set when a compare match occurs between the Timer/Counter0 and the data in OCR0A – Output Compare Register0. OCF0A is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, OCF0A is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE0A (Timer/Counter0 Compare Match Interrupt Enable), and OCF0A are set, the Timer/Counter0 Compare Match Interrupt is executed.
Bit 0 – TOV0 Timer/Counter 0, Overflow Flag
The bit TOV0 is set when an overflow occurs in Timer/Counter0. TOV0 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, TOV0 is cleared by writing a logic one to the flag. When the SREG I-bit, TOIE0 (Timer/Counter0 Overflow Interrupt Enable), and TOV0 are set, the Timer/Counter 0 Overflow interrupt is executed.
The setting of this flag is dependent on the WGM0[2:0] bit setting. Refer to bit description of WGM0 in TCCR0A.