31.2 Overview

The Analog-to-Digital Converter (ADC) is a 12-bit Successive Approximation Register (SAR) ADC, with a sampling rate up to 130 ksps at 12-bit resolution. The ADC is connected to an analog input multiplexer for selection between multiple single-ended or differential inputs. In single-ended conversions, the ADC measures the voltage between the selected input and 0V (GND). In differential conversions, the ADC measures the voltage between two selected input channels. The selected ADC input channels can either be internal (e.g., a voltage reference) or external analog input pins.

An ADC conversion can be started by software, or by using the Event System (EVSYS) to route an event from other peripherals. This makes it possible to do a periodic sampling of input signals, trigger an ADC conversion on a special condition or trigger an ADC conversion in Standby sleep mode.

A digital window compare feature is available for monitoring the input signal and can be configured only to trigger an interrupt if the sample is below or above a user-defined threshold, or inside or outside a user-defined window, with minimum software intervention required.

The ADC input signal is fed through a sample-and-hold circuit which ensures that the input voltage to the ADC is held at a constant level during sampling.

The ADC supports sampling in bursts where a configurable number of conversions are accumulated into a single ADC result (Sample Accumulation). Furthermore, a sample delay can be configured to tune the ADC burst sampling frequency away from any harmonic noise aliased from the sampled signal.

This device has one instance of the ADC peripheral: ADC0.