100
2486AA–AVR–02/2013
ATmega8(L)
The Output Compare Registers contain a 16-bit value that is continuously compared with the
counter value (TCNT1). A match can be used to generate an Output Compare Interrupt, or to
generate a waveform output on the OC1x pin.
The Output Compare Registers are 16-bit in size. To ensure that both the high and Low bytes
are written simultaneously when the CPU writes to these registers, the access is performed
using an 8-bit temporary High byte Register (TEMP). This temporary register is shared by all the
Input Capture Register
1 – ICR1H and ICR1L
The Input Capture is updated with the counter (TCNT1) value each time an event occurs on the
ICP1 pin (or optionally on the Analog Comparator Output for Timer/Counter1). The Input Cap-
ture can be used for defining the counter TOP value.
The Input Capture Register is 16-bit in size. To ensure that both the high and Low bytes are read
simultaneously when the CPU accesses these registers, the access is performed using an 8-bit
temporary High byte Register (TEMP). This temporary register is shared by all the other 16-bit
Timer/Counter
Interrupt Mask
Note:
1. This register contains interrupt control bits for several Timer/Counters, but only Timer1 bits are
described in this section. The remaining bits are described in their respective timer sections
Bit 5 – TICIE1: Timer/Counter1, Input Capture Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Input Capture Interrupt is enabled. The corresponding Interrupt
Bit 4 – OCIE1A: Timer/Counter1, Output Compare A Match Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Output Compare A match interrupt is enabled. The corresponding
TIFR, is set.
Bit 3 – OCIE1B: Timer/Counter1, Output Compare B Match Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Output Compare B match interrupt is enabled. The corresponding
TIFR, is set.
Bit 2 – TOIE1: Timer/Counter1, Overflow Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally
enabled), the Timer/Counter1 Overflow Interrupt is enabled. The corresponding Interrupt Vector
Bit
765
4321
0
ICR1[15:8]
ICR1H
ICR1[7:0]
ICR1L
Read/Write
R/W
Initial Value
000
0000
0
Bit
765
4321
0
OCIE2
TOIE2
TICIE1
OCIE1A
OCIE1B
TOIE1
–
TOIE0
TIMSK
Read/Write
R/W
R
R/W
Initial Value
000
0000
0