52832 ADC just do samle one time

RE: 52832 ADC just do samle one time

Alice — Tue, 18 Jul 2017 12:44:06 GMT

Well done! It's OK now.

RE: 52832 ADC just do samle one time

Jørgen Holmefjord — Tue, 18 Jul 2017 11:57:22 GMT

Hi Alice,

I see you use low power mode in the SAADC driver. There is some issues with this mode in SDK 12.x.0 driver. You should use the driver (nrf_drv_saadc.c) from SDK 13 instead. I tested this whit your code, and it seems to solve the issue. I would also suggest that you enable burst mode in saadc_init() if using oversample, to avoid having to wait for multiple calls to nrf_drv_saadc_sample() to get one result:

channel_config.burst = NRF_SAADC_BURST_ENABLED;

Best regards,

Jørgen

RE: 52832 ADC just do samle one time

Alice — Tue, 18 Jul 2017 09:13:51 GMT

Hi Wojtek, yes, I have started SAADC after each sampling.

RE: 52832 ADC just do samle one time

Alice — Tue, 18 Jul 2017 09:12:16 GMT

Hi Jørgen , I check the err_code for the nrf_drv_saadc_sample as you said, no error. Do you have a similar example that adc works at low power mode? I have no idear to solve the problem. It's too stranged.

RE: 52832 ADC just do samle one time

Wojtek — Mon, 17 Jul 2017 15:11:21 GMT

Just a blind shot, because I cannot check your code right now. Do you start SAADC after each sampling? You have to.

RE: 52832 ADC just do samle one time

Jørgen Holmefjord — Mon, 17 Jul 2017 14:57:01 GMT

I can't see anything in particular that should stop the sampling after one sample, but you should try checking all error codes, to make sure no functions return errors:

In battery_voltage_timeout_handler(), check the error code from nrf_drv_saadc_sample():

uint32_t err_code = nrf_drv_saadc_sample(); //Trigger the SAADC SAMPLE task
APP_ERROR_CHECK(err_code);

You should also check error codes on calls to app_timer_create and app_timer_start.

RE: 52832 ADC just do samle one time

Alice — Mon, 17 Jul 2017 12:06:02 GMT

The whole project is too large, so I upload the main.c document, pls see the attachment. Thanks.

RE: 52832 ADC just do samle one time

Jørgen Holmefjord — Mon, 17 Jul 2017 11:05:42 GMT

Could you upload the code for review/debugging?

RE: 52832 ADC just do samle one time

Alice — Mon, 17 Jul 2017 02:25:41 GMT

I use APP_TIMER_DEF(m_battery_voltage_id);to creat a timer and then I use nrf_drv_saadc_sample() to trigger the ADC to sample when the timer timeout. The SAADC_SAMPLES_IN_BUFFER is 1, I also try other number such as 5, but the result is the same. I know the code is runing well ,because the timer is running all the time and I will prinf a debug information when timer timeout.

RE: 52832 ADC just do samle one time

Jørgen Holmefjord — Fri, 14 Jul 2017 09:35:26 GMT

Your code does not show how you trigger sampling. It is very hard to say why it only trigger one sample without seeing the rest of your code. Do you know if your code continues to run or if it halts at an error? What is the size of SAADC_SAMPLES_IN_BUFFER?