ATmega1281 Atmel Corporation, ATmega1281 Datasheet - Page 191

• Manufacturer Part Number: ATmega1281
• Manufacturer: Atmel Corporation

Specifications of ATmega1281

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 16
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

20.10.3
20.10.4
20.10.5
2549N–AVR–05/11
TCNT2 – Timer/Counter Register
OCR2A – Output Compare Register A
OCR2B – Output Compare Register B
Table 20-9.
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 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.
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
ATmega640/1280/1281/2560/2561
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
4
0
4
0
4
0
OCR2A[7:0]
OCR2B[7:0]
TCNT2[7:0]
No clock source (Timer/Counter stopped)
R/W
R/W
R/W
3
0
3
0
3
0
clk
clk
clk
clk
clk
clk
T
T2S
clk
T
2
T2S
T2S
2
T2S
S
S
/1024 (From prescaler)
R/W
R/W
R/W
T2S
/256 (From prescaler)
/128 (From prescaler)
2
0
2
0
2
0
/32 (From prescaler)
/64 (From prescaler)
/8 (From prescaler)
Description
/(No prescaling)
R/W
R/W
R/W
1
0
1
0
1
0
R/W
R/W
R/W
0
0
0
0
0
0
OCR2A
OCR2B
TCNT2
191