38.1 Overview

The Analog-to-Digital Converter (ADC) converts analog signals to digital values. The ADC has up to 12-bit resolution, and is capable of a sampling rate of up to 1 MSPS. The input selection is flexible, and both differential and single-ended measurements can be performed. In addition, several internal signal inputs are available. The ADC can provide both signed and unsigned results.

ADC measurements can be started by either application software or an incoming event from another peripheral in the device. ADC measurements can be started with predictable timing and without software intervention.

Both internal and external reference voltages can be used.

An integrated temperature sensor is available to use with the ADC. The INTREF voltage reference (supplied by the bandgap), as well as the scaled I/O and core voltages, 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.

The ADC can be configured for 8-bit, 10-bit or 12-bit results. ADC conversion results are provided left-adjusted or right-adjusted, which eases calculation when the result is represented as a signed value. It is possible to use DMA to move ADC results directly to memory or peripherals when conversions are done.

The SAM C20/C21 has two ADC instances, ADC0 and ADC1. The two inputs can be sampled simultaneously, as each ADC includes a dedicated sample and hold (S&H)circuit.