ATmega1281R231 Atmel Corporation, ATmega1281R231 Datasheet - Page 40

• Manufacturer Part Number: ATmega1281R231
• Manufacturer: Atmel Corporation

Specifications of ATmega1281R231

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 16 MHz
• Max I/o Pins: 54
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Crypto Engine: AES
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Operating Voltage (vcc): 1.8 to 3.6
• Timers: 6
• Frequency Band: 2.4 GHz
• Max Data Rate (mb/s): 2
• Antenna Diversity: Yes
• External Pa Control: Yes
• Power Output (dbm): 3
• Receiver Sensitivity (dbm): -101
• Receive Current Consumption (ma): 13.2
• Transmit Current Consumption (ma): 14.4
• Link Budget (dbm): 104

10. System Clock and Clock Options
10.1
10.2
10.2.1
2549N–AVR–05/11
Overview
Clock Systems and their Distribution
CPU Clock – clk
This section describes the clock options for the AVR microcontroller.
Figure 10-1
clocks need not be active at a given time. In order to reduce power consumption, the clocks to
modules not being used can be halted by using different sleep modes, as described in
Management and Sleep Modes” on page
Figure 10-1. Clock Distribution
The CPU clock is routed to parts of the system concerned with operation of the AVR core.
Examples of such modules are the General Purpose Register File, the Status Register and the
data memory holding the Stack Pointer. Halting the CPU clock inhibits the core from performing
general operations and calculations.
CPU
Asynchronous
Timer/Counter
Timer/Counter
Oscillator
presents the principal clock systems in the AVR and their distribution. All of the
General I/O
Modules
External Clock
clk
clk
ASY
I/O
ATmega640/1280/1281/2560/2561
System Clock
Control Unit
AVR Clock
Multiplexer
Prescaler
Clock
ADC
52. The clock systems are detailed below.
Source clock
clk
Oscillator
ADC
Crystal
CPU Core
clk
clk
Reset Logic
CPU
FLASH
Crystal Oscillator
Watchdog clock
Low-frequency
Watchdog Timer
RAM
Watchdog
Oscillator
Calibrated RC
Flash and
EEPROM
Oscillator
“Power
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