RE: nRF Connect SDK - SAADC example (non blocking internal timer) - note on the sample app

Håkon Alseth — Tue, 17 Sep 2024 12:15:31 GMT

Hi,

[quote user="STE"]

- configure the SAADC to sample two external analog input and also sample the internal VBAT;

[/quote]

Then you need to assign one of the channels to "NRF_SAADC_INPUT_VDD".

The default configuration when using macro "SAADC_CHANNEL_SE_ACQ_3US" is to use the internal 0.6V reference, so your VDD input voltage will scale towards this set reference.

[quote user="STE"]- setup the SAADC able to work with the Timer2 and 200Hz of sample frequency because I need to get samples at exactly 5ms of time.[/quote]

You can have a look at one of the nrfx_timer samples on how to setup a 200 Hz (5ms) timer, and combine that with one of the saadc-samples that matches your use-case the best.

Kind regards,

Håkon

RE: nRF Connect SDK - SAADC example (non blocking internal timer) - note on the sample app

STE — Thu, 12 Sep 2024 14:41:33 GMT

Dear Alseth,

thanks for your reply!

Using the settings below, as I did into my first post, I was able to get the sample design properly working.

I've also tested the building without sysbuild as your request (with the project changes listed in my post not with the original CMakeLists.txt files) and seems also working properly.

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using Zephyr OS v3.6.99-100befc70c74 ***
[00:00:00.365,325] <inf> NRFX_EXAMPLE: Starting nrfx_saadc advanced non-blocking sampling with internal timer example.
[00:00:00.385,375] <inf> NRFX_EXAMPLE: GPIOTE status: initialized
[00:00:00.385,467] <inf> NRFX_EXAMPLE: SAADC event: CALIBRATEDONE
[00:00:00.385,498] <inf> NRFX_EXAMPLE: SAADC event: READY
[00:00:00.385,528] <inf> NRFX_EXAMPLE: SAADC event: BUF_REQ
[00:00:00.385,772] <inf> NRFX_EXAMPLE: SAADC event: DONE
[00:00:00.385,803] <inf> NRFX_EXAMPLE: Sample buffer address == 0x20001126
[00:00:00.385,803] <inf> NRFX_EXAMPLE: [Sample 0] value == 41
[00:00:00.385,803] <inf> NRFX_EXAMPLE: [Sample 1] value == 54
[00:00:00.385,833] <inf> NRFX_EXAMPLE: [Sample 2] value == 41
[00:00:00.385,833] <inf> NRFX_EXAMPLE: SAADC event: BUF_REQ
[00:00:00.386,138] <inf> NRFX_EXAMPLE: SAADC event: DONE
[00:00:00.386,169] <inf> NRFX_EXAMPLE: Sample buffer address == 0x2000112c
[00:00:00.386,169] <inf> NRFX_EXAMPLE: [Sample 0] value == 57
[00:00:00.386,199] <inf> NRFX_EXAMPLE: [Sample 1] value == 47
[00:00:00.386,199] <inf> NRFX_EXAMPLE: [Sample 2] value == 61
[00:00:00.386,230] <inf> NRFX_EXAMPLE: SAADC event: BUF_REQ
[00:00:00.386,505] <inf> NRFX_EXAMPLE: SAADC event: DONE
[00:00:00.386,535] <inf> NRFX_EXAMPLE: Sample buffer address == 0x20001126
[00:00:00.386,535] <inf> NRFX_EXAMPLE: [Sample 0] value == 51
[00:00:00.386,566] <inf> NRFX_EXAMPLE: [Sample 1] value == 66
[00:00:00.386,566] <inf> NRFX_EXAMPLE: [Sample 2] value == 54
[00:00:00.386,596] <inf> NRFX_EXAMPLE: SAADC event: BUF_REQ
[00:00:00.386,901] <inf> NRFX_EXAMPLE: SAADC event: DONE
[00:00:00.386,901] <inf> NRFX_EXAMPLE: Sample buffer address == 0x2000112c
[00:00:00.386,901] <inf> NRFX_EXAMPLE: [Sample 0] value == 67
[00:00:00.386,932] <inf> NRFX_EXAMPLE: [Sample 1] value == 58
[00:00:00.386,932] <inf> NRFX_EXAMPLE: [Sample 2] value == 71
[00:00:00.386,962] <inf> NRFX_EXAMPLE: SAADC event: FINISHED

I kindly ask you if you can help me to modify this sample design in order to achieve these two goal:

- configure the SAADC to sample two external analog input and also sample the internal VBAT;

- setup the SAADC able to work with the Timer2 and 200Hz of sample frequency because I need to get samples at exactly 5ms of time.

Coud you please point me how to do that?

Thanks and best regards!

RE: nRF Connect SDK - SAADC example (non blocking internal timer) - note on the sample app

Håkon Alseth — Thu, 12 Sep 2024 13:01:36 GMT

Hi,

There are some incompatibilities with the cmake macros when building with sysbuild.

For now, I would recommend that you build without sysbuild, like shown here:

Could you try this and see if it works now?

Kind regards,

Håkon