AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 165

• Manufacturer Part Number: AT90USB1286-16MU
• Description: Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
• Manufacturer: ATMEL [ATMEL Corporation]

15.8.3
15.8.4
15.8.5
7593A–AVR–02/06
Timer/Counter Register – TCNT2
Output Compare Register A – OCR2A
Output Compare Register B – OCR2B
• Bit 3 – WGM22: Waveform Generation Mode
See the description in the
• Bit 2:0 – CS22:0: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter, see
15-8.
Table 15-8.
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 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 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.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
CS22
0
0
0
0
1
1
1
1
7
TCNT2[7:0]
R/W
0
7
OCR2A[7:0]
R/W
0
7
OCR2B[7:0]
R/W
0
Clock Select Bit Description
CS21
0
0
1
1
0
0
1
1
6
R/W
0
6
R/W
0
6
R/W
0
“Timer/Counter Control Register A – TCCR2A” on page
CS20
5
R/W
0
5
R/W
0
5
R/W
0
0
1
0
1
0
1
0
1
4
R/W
0
4
R/W
0
4
R/W
0
Description
No clock source (Timer/Counter stopped).
clk
clk
clk
clk
clk
clk
clk
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)
3
R/W
0
3
R/W
0
3
R/W
0
2
R/W
0
2
R/W
0
2
R/W
0
1
R/W
0
1
R/W
0
1
R/W
0
AT90USB64/128
0
R/W
0
0
R/W
0
0
R/W
0
TCNT2
OCR2A
OCR2B
161.
Table
165