ATmega8 Atmel Corporation, ATmega8 Datasheet - Page 74

• Manufacturer Part Number: ATmega8
• Manufacturer: Atmel Corporation

Specifications of ATmega8

• 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
• Output Compare Channels: 3
• Input Capture Channels: 1
• Pwm Channels: 3
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Special Function IO
Register – SFIOR
74
ATmega8(L)
sampling, the maximum frequency of an external clock it can detect is half the sampling fre-
quency (Nyquist sampling theorem). However, due to variation of the system clock frequency
and duty cycle caused by Oscillator source (crystal, resonator, and capacitors) tolerances, it is
recommended that maximum frequency of an external clock source is less than f
An external clock source can not be prescaled.
Figure 31. Prescaler for Timer/Counter0 and Timer/Counter1
Note:
• Bit 0 – PSR10: Prescaler Reset Timer/Counter1 and Timer/Counter0
When this bit is written to one, the Timer/Counter1 and Timer/Counter0 prescaler will be reset.
The bit will be cleared by hardware after the operation is performed. Writing a zero to this bit will
have no effect. Note that Timer/Counter1 and Timer/Counter0 share the same prescaler and a
reset of this prescaler will affect both timers. This bit will always be read as zero.
Bit
Read/Write
Initial Value
PSR10
clk
T0
T1
I/O
1. The synchronization logic on the input pins (
Synchronization
Synchronization
R
7
–
0
R
6
–
0
R
5
–
0
clk
Clear
T1
R
4
–
0
ACME
R/W
3
0
T1/T0)
PUD
R/W
is shown in
2
0
(1)
PSR2
R/W
1
0
Figure 30 on page 73
PSR10
R/W
0
0
clk
T0
clk_I/O
SFIOR
2486Z–AVR–02/11
/2.5.