ATmega8A Atmel Corporation, ATmega8A Datasheet - Page 73

• Manufacturer Part Number: ATmega8A
• Manufacturer: Atmel Corporation

Specifications of ATmega8A

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 2
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• 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): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Pwm Channels: 3
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

14.7
14.7.1
14.7.2
14.7.3
8159D–AVR–02/11
Register Description
TCCR0 – Timer/Counter Control Register
TCNT0 – Timer/Counter Register
TIMSK – Timer/Counter Interrupt Mask Register
• Bit 2:0 – CS02:0: Clock Select
The three clock select bits select the clock source to be used by the Timer/Counter.
Table 14-2.
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.
• Bit 0 – TOIE0: Timer/Counter0 Overflow Interrupt Enable
When the TOIE0 bit is written to one, and the I-bit in the Status Register is set (one), the
Timer/Counter0 Overflow interrupt is enabled. The corresponding interrupt is executed if an
overflow in Timer/Counter0 occurs, i.e., when the TOV0 bit is set in the Timer/Counter Interrupt
Flag Register – TIFR.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
CS02
0
0
0
0
1
1
1
1
CS01
0
0
1
1
0
0
1
1
Clock Select Bit Description
OCIE2
R/W
R/W
R
7
–
0
7
0
7
0
CS00
TOIE2
0
1
0
1
0
1
0
1
R/W
R/W
R
6
–
0
6
0
6
0
Description
No clock source (Timer/Counter stopped).
clk
clk
clk
clk
clk
External clock source on T0 pin. Clock on falling edge.
External clock source on T0 pin. Clock on rising edge.
TICIE1
R/W
R/W
I/O
I/O
I/O
I/O
I/O
R
5
–
0
5
0
5
0
/(No prescaling)
/8 (From prescaler)
/64 (From prescaler)
/256 (From prescaler)
/1024 (From prescaler)
OCIE1A
R/W
R/W
R
4
–
0
4
0
4
0
TCNT0[7:0]
OCIE1B
R/W
R/W
R
3
–
0
3
0
3
0
TOIE1
CS02
R/W
R/W
R/W
2
0
2
0
2
0
CS01
R/W
R/W
R/W
1
0
1
0
1
–
0
ATmega8A
TOIE0
CS00
R/W
R/W
R/W
0
0
0
0
0
0
TCCR0
TCNT0
TIMSK
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