ATmega64A
17.9.2
TCNT2 – Timer/Counter Register
Bit
7
6
5
4
3
2
1
0
0x24 (0x44)
Read/Write
Initial Value
TCNT2[7:0]
TCNT2
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
The Timer/Counter Register gives direct access, both for read and write operations, to the
Timer/Counter unit 8-bit counter. Writing to the TCNT2 Register blocks (removes) the Compare
Match on the following timer clock. Modifying the counter (TCNT2) while the counter is running,
introduces a risk of missing a Compare Match between TCNT2 and the OCR2 Register.
17.9.3
OCR2 – Output Compare Register
Bit
7
6
5
4
3
2
1
0
0x23 (0x43)
Read/Write
Initial Value
OCR2[7:0]
OCR2
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
The Output Compare Register contains an 8-bit value that is continuously compared with the
counter value (TCNT2). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC2 pin.
17.9.4
TIMSK – Timer/Counter Interrupt Mask Register
Bit
0x37 (0x57)
7
6
5
4
OCIE1A
R/W
0
3
OCIE1B
R/W
0
2
TOIE1
R/W
0
1
OCIE0
R/W
0
0
TOIE0
R/W
0
OCIE2
TOIE2
TICIE1
R/W
0
TIMSK
Read/Write
Initial Value
R/W
0
R/W
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, for example, 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, for example, when the TOV2 bit is set in the Timer/Counter
Interrupt Flag Register – TIFR.
17.9.5
TIFR – Timer/Counter Interrupt Flag Register
Bit
0x36 (0x56)
7
6
5
4
OCF1A
R/W
0
3
OCF1B
R/W
0
2
TOV1
R/W
0
1
OCF0
R/W
0
0
TOV0
R/W
0
OCF2
TOV2
ICF1
R/W
0
TIFR
Read/Write
Initial Value
R/W
0
R/W
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.
160
8160C–AVR–07/09
ATMEL [ ATMEL ]
