RE: SAADC only fills sample buffer with one sample per channel on each trigger

tommy.lane — Tue, 27 Nov 2018 16:31:35 GMT

[quote userid="14926" url="~/f/nordic-q-a/40958/saadc-only-fills-sample-buffer-with-one-sample-per-channel-on-each-trigger/159297"]When the requested buffer is filled with samples, an event of type NRF_DRV_SAADC_EVT_DONE is generated.[/quote]

Looking at it now it's obviously what it means. When I initially read this section the "[when filled with samples]" section seemed out of place, and unnecessary. If the goal of this sentence is to convey that each sample event only fills one sample location per channel then clearly stating "Each sampling event only fills a single array index per channel during the acquire event, when the requested buffer is filled with samples, an event of type NRF_DRV_SAADC_EVT_DONE is generated."

Wording could use some work, but this is roughly how I feel it should read.

Thanks for getting back to me so quickly!

RE: SAADC only fills sample buffer with one sample per channel on each trigger

Jørgen Holmefjord — Tue, 27 Nov 2018 16:19:36 GMT

Hi,

Can you point to the part of documentation that confuse you? The SAADC peripheral documentation is quite clear on this:

In scan mode, one SAMPLE task will trigger one conversion per enabled channel.

To me, this is also understandable from the SDK driver doucmentation:

To trigger sampling, call the function nrf_drv_saadc_sample or, through PPI, use the task SAMPLE from SAADC. nrf_drv_saadc_sample_task_get can be used to get the task address. Single sampling triggers conversion on all initialized channels. When the requested buffer is filled with samples, an event of type NRF_DRV_SAADC_EVT_DONE is generated.

Best regards,
Jørgen