How to Calibrate SAADC for temperature compensation Example code

RE: How to Calibrate SAADC for temperature compensation Example code

adnan arshad — Mon, 17 Feb 2020 09:59:21 GMT

I have tried this link and found the issue of my problem.

https://devzone.nordicsemi.com/f/nordic-q-a/48462/questions-on-saadc-calibration-gain-best-use

RE: How to Calibrate SAADC for temperature compensation Example code

adnan arshad — Fri, 14 Feb 2020 13:28:55 GMT

I have also followed the following example

https://devzone.nordicsemi.com/f/nordic-q-a/32982/can-t-stop-saadc/127645#127645

it causes all the 5 samples to be corrupted after calibration.

RE: How to Calibrate SAADC for temperature compensation Example code

adnan arshad — Thu, 13 Feb 2020 09:10:02 GMT

Dear Kenneth,

I have followed this

https://devzone.nordicsemi.com/f/nordic-q-a/34785/saadc---calibration

and my code snipped is

if(saadc_calibrate == true)
{
while(nrf_drv_saadc_calibrate_offset() != NRF_SUCCESS); //Trigger calibration task
nrf_saadc_disable();
while(NRF_SAADC->STATUS == (SAADC_STATUS_STATUS_Busy << SAADC_STATUS_STATUS_Pos));
nrf_saadc_enable();
while(NRF_SAADC->STATUS == (SAADC_STATUS_STATUS_Busy << SAADC_STATUS_STATUS_Pos));

SEGGER_RTT_printf(0, "Calibration Done\n\r");
saadc_calibrate = false;
}

But still the first wrong sample issue persists.

RE: How to Calibrate SAADC for temperature compensation Example code

Kenneth — Wed, 12 Feb 2020 15:41:28 GMT

The first link I shared contain an example that does this. Check out directly link (answer to question 5):
https://devzone.nordicsemi.com/f/nordic-q-a/39454/calibrating-saadc-on-nrf52832/152901#152901

Kenneth

RE: How to Calibrate SAADC for temperature compensation Example code

adnan arshad — Wed, 12 Feb 2020 13:32:19 GMT

Thanks Kenneth,

Please refer to some example code of doing this remedy.

RE: How to Calibrate SAADC for temperature compensation Example code

Kenneth — Wed, 12 Feb 2020 13:05:00 GMT

I think the example I linked already handle this as described.

RE: How to Calibrate SAADC for temperature compensation Example code

adnan arshad — Wed, 12 Feb 2020 10:36:24 GMT

I have used the following example and the issue is that after calibration done the first sample of saadc read is in -ive value or some thing 1,2,3,5,6 etc which is for more away from the actual value 1622-1630.

https://github.com/NordicPlayground/nRF52-ADC-examples/blob/master/saadc_low_power/main.c

RE: How to Calibrate SAADC for temperature compensation Example code

Kenneth — Tue, 11 Feb 2020 12:17:23 GMT

You can execute SAADC offset calibration at given intervals (or when temperature changes). Also check out:
https://devzone.nordicsemi.com/f/nordic-q-a/39454/calibrating-saadc-on-nrf52832