Datasheet

22. ADC - Analog to Digital Converter
22.1. Features
• 10-bit Resolution
• 0.5 LSB Integral Non-Linearity
• ±2 LSB Absolute Accuracy
• 8 - 250μs Conversion Time
• Up to 120kSPS at Maximum Resolution
• 11 Multiplexed Single Ended Input Channels
• Three differential input channels with accurate (5%) programmable gain 5, 10, 20 and 40
• Optional Left Adjustment for ADC Result Readout
• 0 - V
CC
ADC Input Voltage Range
• Selectable 2.56V ADC Reference Voltage
• Free Running or Single Conversion Mode
• ADC start conversion by auto triggering on interrupt sources
• Interrupt on ADC Conversion Complete
• Sleep Mode Noise Canceler
• Temperature Sensor
• LiN address sense (ISRC voltage measurement)
• VCC voltage measurement
22.2. Overview
The device features a 10-bit successive approximation ADC. The ADC is connected to a 15-channel
Analog Multiplexer which allows 11 single-ended voltage inputs. The single-ended voltage inputs refer to
0V (GND).
The device also supports three differential voltage input amplifiers which are equipped with a
programmable gain stage, providing amplification steps of 14dB (5×), 20dB (10×), 26dB (20×), or 32dB
(40×) on the differential input voltage before the A/D conversion. On the amplified channels, 8-bit
resolution can be expected.
The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is held at a
constant level during conversion. A block diagram of the ADC is shown below.
The ADC has a separate analog supply voltage pin, AV
CC
. AV
CC
must not differ more than ±0.3V from
V
CC
. See section ADC Noise Canceler on how to connect this pin.
The Power Reduction ADC bit in the Power Reduction Register (PRR.PRADC) must be written to '0' in
order to be enable the ADC.
The ADC converts an analog input voltage to a 10-bit digital value through successive approximation. The
minimum value represents GND and the maximum value represents the voltage on the AREF pin minus 1
LSB. Optionally, AV
CC
or an internal 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 must be decoupled by
an external capacitor at the AREF pin to improve noise immunity.
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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