Datasheet

105
7728G–AVR–06/10
ATtiny87/ATtiny167
10.11.5 Timer/Counter0 Interrupt Mask Register – TIMSK0
• Bit 7:2 – Res: Reserved Bits
These bits are reserved in the ATtiny87/167 and will always read as zero.
• Bit 1 – OCIE0A: Timer/Counter0 Output Compare Match A Interrupt Enable
When the OCIE0A bit is written to one and the I-bit in the Status Register is set (one), the
Timer/Counter0 Compare Match A interrupt is enabled. The corresponding interrupt is exe-
cuted if a compare match in Timer/Counter0 occurs, i.e., when the OCF0A bit is set in the
Timer/Counter0 Interrupt Flag Register – TIFR0.
• Bit 0 – TOIE0: Timer/Counter0 Overflow Interrupt Enable
When the TOIE0 bit is written to one and the I-bit in the Status Register is set (one), the
Timer/Counter0 Overflow interrupt is enabled. The corresponding interrupt is executed if an
overflow in Timer/Counter0 occurs, i.e., when the TOV0 bit is set in the Timer/Counter0 Inter-
rupt Flag Register – TIFR0.
10.11.6 Timer/Counter0 Interrupt Flag Register – TIFR0
• Bit 7:2 – Res: Reserved Bits
These bits are reserved in the ATtiny87/167 and will always read as zero.
• Bit 1 – OCF0A: Output Compare Flag 0 A
The OCF0A bit is set (one) when a compare match occurs between the Timer/Counter0 and
the data in OCR0A – Output Compare Register0. OCF0A is cleared by hardware when exe-
cuting the corresponding interrupt handling vector. Alternatively, OCF0A is cleared by writing a
logic one to the flag. When the I-bit in SREG, OCIE0 (Timer/Counter0 Compare match Inter-
rupt Enable), and OCF0A are set (one), the Timer/Counter0 Compare match Interrupt is
executed.
• Bit 0 – TOV0: Timer/Counter0 Overflow Flag
The TOV0 bit is set (one) 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, TOIE0A (Timer/Counter0
Overflow Interrupt Enable), and TOV0 are set (one), the Timer/Counter0 Overflow interrupt is
executed. In PWM mode, this bit is set when Timer/Counter0 changes counting direction at
0x00.
Bit 76543210
––––––OCIE0ATOIE0 TIMSK0
Read/Write R R R R R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Bit 76543210
––––––OCF0ATOV0 TIFR0
Read/Write R R R R R R R/W R/W
Initial Value 00000000