ATMEGA8A-AUR Atmel, ATMEGA8A-AUR Datasheet - Page 120

• Manufacturer Part Number: ATMEGA8A-AUR
• Description: MCU AVR 8KB FLASH 16MHZ 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8A-AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

17.10 Timer/Counter Prescaler
8159D–AVR–02/11
Figure 17-12. Prescaler for Timer/Counter2
The clock source for Timer/Counter2 is named clk
system I/O clock clk
clocked from the TOSC1 pin. This enables use of Timer/Counter2 as a Real Time Counter
(RTC). When AS2 is set, pins TOSC1 and TOSC2 are disconnected from Port B. A crystal can
then be connected between the TOSC1 and TOSC2 pins to serve as an independent clock
source for Timer/Counter2. The Oscillator is optimized for use with a 32.768kHz crystal. Apply-
ing an external clock source to TOSC1 is not recommended.
For Timer/Counter2, the possible prescaled selections are: clk
clk
Setting the PSR2 bit in SFIOR resets the prescaler. This allows the user to operate with a pre-
dictable prescaler.
T2S
/128, clk
TOSC1
clk
PSR2
CS20
CS21
CS22
T2S
AS2
I/O
/256, and clk
I/O
. By setting the AS2 bit in ASSR, Timer/Counter2 is asynchronously
T2S
clk
/1024. Additionally, clk
T2S
TIMER/COUNTER2 CLOCK SOURCE
Clear
0
T2S
10-BIT T/C PRESCALER
. clk
clk
T2S
T2S
T2
as well as 0 (stop) may be selected.
is by default connected to the main
T2S
/8, clk
ATmega8A
T2S
/32, clk
T2S
/64,
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