RE: How the ASYNC read API work in ADC with sample code

Karl Ylvisaker — Tue, 25 Jan 2022 15:10:12 GMT

Hello,

Thank you for your patience with this.

[quote user=""]What is the difference between the Async Read ApI and the Normal Read API of the ADC ?[/quote]

The difference between the two is whether or not the sampling will happen asynchronously or not.
In essence, this means that completion of the sampling will be signaled with a polling event, you can read more about this in the polling API documentation.
If you look into the adc_nrfx_saadc.c driver, you could see how the CONFIG_ADC_ASYNC kconfig option changes the sampling procedure.

[quote user=""]

Specially thirds argument of API

struct k_poll_signal *async) what exactly we need to set in this?

[/quote]

You will need to provide a k_poll_signal which is tied to a poll event.
You could see how this could be done in the test_task_asynchronous_call function of the zephyr driver test.

[quote user=""]Can we configure the multiple channel for the ADC Async read [/quote]

Yes, if multiple channels are enabled then the SAADC will enter scan mode and sample each enabled channel sequentially when a sampling is triggered.

Best regards,
Karl