attiny261a-xu ATMEL Corporation, attiny261a-xu Datasheet - Page 141

• Manufacturer Part Number: attiny261a-xu
• Description: 8-bit Avr Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

15.3
8197B–AVR–01/10
Operation
Figure 15-1. Analog to Digital Converter Block Schematic
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
V
The voltage reference for the ADC may be selected by writing to the REFS2:0 bits in ADCSRB
and ADMUX registers. The VCC supply, the AREF pin or an internal 1.1V / 2.56V voltage refer-
ence may be selected as the ADC voltage reference. Optionally the internal 1.1V / 2.56V voltage
ADC10
CC
ADC9
ADC8
ADC7
ADC6
ADC5
ADC4
ADC3
ADC2
ADC1
ADC0
AGND
AREF
VCC
, the voltage on the AREF pin or an internal 1.1V / 2.56V voltage reference.
8-BIT DATA BUS
INTERNAL 2.56/1.1V
INTERNAL 1.18V
TEMPERATURE
REFERENCE
REFERENCE
SENSOR
REGISTER B (ADCSRB)
ADC CTRL. & STATUS
INPUT
POS.
MUX
INPUT
NEG.
MUX
MUX DECODER
ADC MULTIPLEXER
SELECT (ADMUX)
DIFFERENTIAL SELECTION
SINGLE ENDED /
+
-
GAIN
AMPLIFIER
10-BIT DAC
REGISTER A (ADCSRA)
ADC CTRL. & STATUS
MUX
ADC CONVERSION
COMPLETE IRQ
CONVERSION LOGIC
PRESCALER
SAMPLE & HOLD
COMPARATOR
+
-
15
MULTIPLEXER OUTPUT
ADC DATA REGISTER
(ADCH/ADCL)
ADC
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