ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 162

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

18.11.3
18.11.4
18.11.5
162
Atmel ATmega48PA/88PA/168PA [Preliminary]
TCNT2 – Timer/Counter Register
OCR2A – Output Compare Register A
OCR2B – Output Compare Register B
Table 18-9.
If external pin modes are used for the Timer/Counter0, transitions on the T0 pin will clock the
counter even if the pin is configured as an output. This feature allows software control of the
counting.
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 Com-
pare 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 OCR2x
Registers.
The Output Compare Register A 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 OC2A pin.
The Output Compare Register B 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 OC2B pin.
Bit
(0xB2)
Read/Write
Initial Value
Bit
(0xB3)
Read/Write
Initial Value
Bit
(0xB4)
Read/Write
Initial Value
CS22
0
0
0
0
1
1
1
1
Clock Select Bit Description
R/W
R/W
R/W
7
0
7
0
7
0
CS21
0
0
1
1
0
0
1
1
R/W
R/W
R/W
6
0
6
0
6
0
CS20
R/W
R/W
R/W
0
1
0
1
0
1
0
1
5
0
5
0
5
0
R/W
R/W
R/W
Description
No clock source (Timer/Counter stopped).
clk
clk
clk
clk
clk
clk
clk
4
0
4
0
4
0
OCR2A[7:0]
OCR2B[7:0]
TCNT2[7:0]
T2S
T2S
T2S
T2S
T2S
T
T
2
2
S
S
/256 (From prescaler)
/1024 (From prescaler)
/(No prescaling)
/8 (From prescaler)
/32 (From prescaler)
/64 (From prescaler)
/128 (From prescaler)
R/W
R/W
R/W
3
0
3
0
3
0
R/W
R/W
R/W
2
0
2
0
2
0
R/W
R/W
R/W
1
0
1
0
1
0
R/W
R/W
R/W
0
0
0
0
0
0
9223B–AVR–09/11
OCR2A
OCR2B
TCNT2