ATMEGA161-8PI Atmel, ATMEGA161-8PI Datasheet - Page 38

• Manufacturer Part Number: ATMEGA161-8PI
• Description: IC AVR MCU 16K 8MHZ IND 40-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA161-8PI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -
• Other names: ATMEGA1618PI

Timer/Counters
Timer/Counter
Prescalers
38
ATmega161(L)
The ATmega161 provides three general purpose Timer/Counters – two 8-bit T/Cs and
one 16-bit T/C. Timer/Counter2 can optionally be asynchronously clocked from an exter-
nal Oscillator. This Oscillator is optimized for use with a 32.768 kHz watch crystal,
enabling use of Timer/Counter2 as a Real-time Clock (RTC). Timer/Counters 0 and 1
have individual prescaling selection from the same 10-bit prescaling timer.
Timer/Counter2 has its own prescaler. Both these prescalers can be Reset by setting
the corresponding control bits in the Special Functions IO Register (SFIOR). Refer to
page 39 for a detailed description. These Timer/Counters can either be used as a timer
with an internal clock time base or as a counter with an external pin connection, which
triggers the counting.
Figure 29. Prescaler for Timer/Counter0 and 1
For Timer/Counters 0 and 1, the four prescaled selections are: CK/8, CK/64, CK/256,
and CK/1024, where CK is the Oscillator clock. For the two Timer/Counters 0 and 1, CK,
external source and stop can also be selected as clock sources. Setting the PSR10 bit
in SFIOR Resets the prescaler. This allows the user to operate with a predictable pres-
caler. Note that Timer/Counter1 and Timer/Counter0 share the same prescaler and a
Prescaler Reset will affect both Timer/Counters.
PSR10
TCK1
Clear
TCK0
1228D–AVR–02/07