Timer/Counter
Interrupt Mask
Register – TIMSK
Bit
7
OCIE2
R/W
0
6
TOIE2
R/W
0
5
TICIE1
R/W
0
4
OCIE1A
R/W
0
3
OCIE1B
R/W
0
2
TOIE1
R/W
0
1
–
0
TOIE0
R/W
0
TIMSK
Read/Write
Initial Value
R
0
• Bit 7 – OCIE2: Timer/Counter2 Output Compare Match Interrupt Enable
When the OCIE2 bit is written to one and the I-bit in the Status Register is set (one), the
Timer/Counter2 Compare Match interrupt is enabled. The corresponding interrupt is executed if
a Compare Match in Timer/Counter2 occurs (i.e., when the OCF2 bit is set in the Timer/Counter
Interrupt Flag Register – TIFR).
• Bit 6 – TOIE2: Timer/Counter2 Overflow Interrupt Enable
When the TOIE2 bit is written to one and the I-bit in the Status Register is set (one), the
Timer/Counter2 Overflow interrupt is enabled. The corresponding interrupt is executed if an
overflow in Timer/Counter2 occurs (i.e., when the TOV2 bit is set in the Timer/Counter Interrupt
Flag Register – TIFR).
Timer/Counter
Interrupt Flag Register
– TIFR
Bit
7
OCF2
R/W
0
6
TOV2
R/W
0
5
4
OCF1A
R/W
0
3
OCF1B
R/W
0
2
TOV1
R/W
0
1
–
0
TOV0
R/W
0
ICF1
R/W
0
TIFR
Read/Write
Initial Value
R
0
• Bit 7 – OCF2: Output Compare Flag 2
The OCF2 bit is set (one) when a Compare Match occurs between the Timer/Counter2 and the
data in OCR2 – Output Compare Register2. OCF2 is cleared by hardware when executing the
corresponding interrupt Handling Vector. Alternatively, OCF2 is cleared by writing a logic one to
the flag. When the I-bit in SREG, OCIE2 (Timer/Counter2 Compare Match Interrupt Enable), and
OCF2 are set (one), the Timer/Counter2 Compare Match Interrupt is executed.
• Bit 6 – TOV2: Timer/Counter2 Overflow Flag
The TOV2 bit is set (one) when an overflow occurs in Timer/Counter2. TOV2 is cleared by hard-
ware when executing the corresponding interrupt Handling Vector. Alternatively, TOV2 is
cleared by writing a logic one to the flag. When the SREG I-bit, TOIE2 (Timer/Counter2 Overflow
Interrupt Enable), and TOV2 are set (one), the Timer/Counter2 Overflow interrupt is executed. In
PWM mode, this bit is set when Timer/Counter2 changes counting direction at 0x00.
122
ATmega8(L)
2486T–AVR–05/08
ATMEL [ ATMEL ]
