Atmel XMEGA B, User Manual

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325 XMEGA B [DATASHEET]
8291B–AVR–01/2013
26. ADC – Analog-to-Digital Converter
26.1 Features

12-bit resolution

Up to 300 thousand samples per second

Down to 2.3 μ s conversion time with 8-bit resolution

Down to 3.35 μ s conversion time with 12-bit resolution

Differential and single-ended input

Up to 16 single-ended inputs

Up to 16x4 differential inputs without gain

8x4 differential input with gain

Built-in differential gain stage

1/2
x, 1x, 2x, 4x, 8x, 16x, 32x, and 64x gain options

Single, continuous and scan conversion options

Three internal inputs

Internal temperature sensor

V
CC
voltage divided by 10

1.1V bandgap voltage

Internal and external reference options

Compare function for accurate monitoring of user defined thresholds

Optional DMA transfer of conversion results

Optional event triggered conversion for accurate timing

Optional interrupt/event on compare result
26.2 Overview
The ADC converts analog signals to digital values. The ADC has 12-bit resolution and is capable of converting up to 300
thousand samples per second (ksps). The input selection is flexible, and both single-ended and differential
measurements can be done. For differential measurements, an optional gain stage is available to increase the dynamic
range. In addition, several internal signal inputs are available. The ADC can provide both signed and unsigned results.
The ADC measurements can either be started by application software or an incoming event from another peripheral in
the device. The ADC measurements can be started with predictable timing, and without software intervention. It is
possible to use DMA to move ADC results directly to memory or peripherals when conversions are done.
Both internal and external reference voltages can be used. An integrated temperature sensor is available for use with the
ADC. The V
CC
/10 and the bandgap voltage can also be measured by the ADC.
The ADC has a compare function for accurate monitoring of user defined thresholds with minimum software intervention
required.