Analog-to-Digital Converter (ADC) sequence sample

Overview

This sample demonstrates how to use the ADC driver API using sequences.

Depending on the target board, it reads ADC samples from two channels and prints the readings on the console, based on the sequence specifications. Notice how for the whole sequence reading, only one call to the adc_read() API is made. If voltage of the used reference can be obtained, the raw readings are converted to millivolts.

This example constructs an adc device and setups its channels, according to the given devicetree configuration.

Building and Running

Make sure that the ADC is enabled (status = "okay";) and has each channel as a child node, with your desired settings like gain, reference, or acquisition time and oversampling setting (if used). It is also needed to provide an alias adc0 for the desired adc. See boards/nrf52840dk_nrf52840.overlay for an example of such setup.

Building and Running for Nordic nRF52840

The sample can be built and executed for the nRF52840 DK as follows:

west build -b nrf52840dk/nrf52840 samples/drivers/adc/adc_sequence
west flash

To build for another board, change “nrf52840dk/nrf52840” above to that board’s name and provide a corresponding devicetree overlay.

Sample output

You should get a similar output as below, repeated every second:

ADC sequence reading [1]:
- ADC_0, channel 0, 5 sequence samples:
- - 36 = 65mV
- - 35 = 63mV
- - 36 = 65mV
- - 35 = 63mV
- - 36 = 65mV
- ADC_0, channel 1, 5 sequence samples:
- - 0 = 0mV
- - 0 = 0mV
- - 1 = 1mV
- - 0 = 0mV
- - 1 = 1mV

Note

If the ADC is not supported, the output will be an error message.