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ATtiny25/45/85 [DATASHEET]
2586Q–AVR–08/2013
to the OCR1B value. A software write that sets TCNT1 and OCR1B to the same value does not generate a com-
pare match.
A compare match will set the compare interrupt flag OCF1B after a synchronization delay following the compare
event.
12.3.6
OCR1C – Timer/Counter1 Output Compare RegisterC
The output compare register C is an 8-bit read/write register.
The Timer/Counter Output Compare Register C contains data to be continuously compared with Timer/Counter1.
A compare match does only occur if Timer/Counter1 counts to the OCR1C value. A software write that sets TCNT1
and OCR1C to the same value does not generate a compare match. If the CTC1 bit in TCCR1 is set, a compare
match will clear TCNT1.
This register has the same function in normal mode and PWM mode.
12.3.7
TIMSK – Timer/Counter Interrupt Mask Register
Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
Bit 6 – OCIE1A: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Compare
MatchA, interrupt is enabled. The corresponding interrupt at vector $003 is executed if a compare matchA occurs.
The Compare Flag in Timer/Counter1 is set (one) in the Timer/Counter Interrupt Flag Register.
Bit 5 – OCIE1B: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Compare
MatchB, interrupt is enabled. The corresponding interrupt at vector $009 is executed if a compare matchB occurs.
The Compare Flag in Timer/Counter1 is set (one) in the Timer/Counter Interrupt Flag Register.
Bit 2 – TOIE1: Timer/Counter1 Overflow Interrupt Enable
When the TOIE1 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Overflow inter-
rupt is enabled. The corresponding interrupt (at vector $004) is executed if an overflow in Timer/Counter1 occurs.
The Overflow Flag (Timer1) is set (one) in the Timer/Counter Interrupt Flag Register - TIFR.
Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
Bit
7
6
543
210
MSB
LSB
OCR1C
Read/Write
R/W
Initial value
1
Bit
7
6
5
4
3
2
1
0
–
OCIE1A
OCIE1B
OCIE0A
OCIE0B
TOIE1
TOIE0
–
TIMSK
Read/Write
R
R/W
R
Initial value
0