SAADC issue with nRF52

RE: SAADC issue with nRF52

Avi A — Fri, 10 Aug 2018 01:55:57 GMT

Hi Edwin,

I verified once more and found what you said to be right. I had the wrong pin. When I connected P0.02 (AREF) to GND I did see the value going down to zero and go up when I connected the pin to VDD. Thank you for clarifying. I consider this issue resolved.

RE: SAADC issue with nRF52

Avi A — Fri, 10 Aug 2018 01:43:29 GMT

Hi Edwin,

Thank you for your response. I do receive a random value whenever I call it, it does not hang.

Maybe my pin is wrong, I was measuring pin marked as P0.03 (A0). On the board PCA10040 (1.2.4 2018.16) board that I have I find that A0 to A5 are on P8 header. I dont see P0.02 on the board. Can you please clarify if P0.03 (A0) is correct?

I have not yet tried the SDK15\examples\peripheral\saadc mainly because I was trying to get simple version of the SAADC blocking working with my softdevice code before I try out the non-blocking with SAADC-buffer.

RE: SAADC issue with nRF52

Edvin — Thu, 09 Aug 2018 13:01:41 GMT

Does your nrfx_saadc_sample_convert() ever return, or does it hang there forever?

If it returns, and you get a new (but random) value whenever you call it, are you sure that you are measuring on the correct pin? AIN0 is pin P0.02.

Have you tested the saadc example found in SDK15\examples\peripheral\saadc? Here the callback function should be called, but it is not called before it has received 5 measurements, since the size of the saadc-buffer is 5. What is the size of your saadc-buffer?

Best regards,

Edvin

RE: SAADC issue with nRF52

F Iannce — Wed, 08 Aug 2018 18:53:33 GMT

I think your problem is that you are using the blocking function nrfx_saadc_sample_convert(). I believe that this function specifically disables the interrupt until it finishes. If you want to use the interrupt you should look at nrfx_saadc_buffer_convert()...