ATmega1281R231 Atmel Corporation, ATmega1281R231 Datasheet - Page 276

• 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

Figure 26-1. Analog to Digital Converter Block Schematic
26.2
2549N–AVR–05/11
ADC[15:0]
BANDGAP (1.1V)
REFERENCE
REFERENCE
(1.1V/2.56V)
INTERNAL
AVCC
AREF
GND
8-BIT DATABUS
Operation
ADC[2:0]
ADC[10:8]
ADC MULTIPLEXER
SELECT (ADMUX)
The ADC converts an analog input voltage to a 10-bit digital value through successive approxi-
mation. The minimum value represents GND and the maximum value represents the voltage on
the AREF pin minus 1 LSB. Optionally, AVCC or an internal 1.1V or 2.56V reference voltage
may be connected to the AREF pin by writing to the REFSn bits in the ADMUX Register. The
internal voltage reference may thus be decoupled by an external capacitor at the AREF pin to
improve noise immunity.
The analog input channel is selected by writing to the MUX bits in ADMUX and ADCSRB. Any of
the ADC input pins, as well as GND and a fixed bandgap voltage reference, can be selected as
single ended inputs to the ADC. A selection of ADC input pins can be selected as positive and
negative inputs to the differential amplifier.
MUX DECODER
+
-
REGISTER B (ADCSRB)
ADC CTRL & STATUS
AMPLIFIE R
GAIN
ATmega640/1280/1281/2560/2561
10-bit DAC
REGISTER A (ADCSRA)
ADC CTRL & STATUS
ADC CONVERSION
COMPLETE IRQ
PRESCALER
CONVERSION LOGIC
+
-
ADTS[2:0]
START
TRIGGER
SELECT
SAMPLE & HOLD
INTERRUPT
COMPARATOR
ADC
MULTIPLEXER
OUTPUT
FLAGS
15
ADC DATA REGISTER
(ADCH/ADCL)
0
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