SAADC always returns 0 value

[nick_haman]

Whichever input channel I select, I always get a value close to zero.  Here is my test code using VDD as the input source:

static void saadc_init()
{
  uint32_t err = nrfx_saadc_init(NULL, saadc_handler);
  APP_ERROR_CHECK(err);
  
  nrf_saadc_channel_config_t sns_in = NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_VDD);
    err = nrfx_saadc_channel_init(0, &sns_in);
  APP_ERROR_CHECK(err);
  NRF_LOG_INFO("SAADC Initialized");
  
  nrf_saadc_value_t result;
  nrfx_saadc_sample_convert(0, &result);
  
}

In this case, RTT reports that the value is '2'.  This is the case for any input channel I select.

[Jørgen Holmefjord]

Hi,

The nrfx_saadc driver does not support passing NULL as the argument to the config parameter to the init function. If you build in debug config (with symbol DEBUG_NRF defined), you will get an assert from this code.

Try this:

 

nrfx_saadc_config_t saadc_config = NRFX_SAADC_DEFAULT_CONFIG;
uint32_t err = nrfx_saadc_init(&saadc_config, saadc_handler);
APP_ERROR_CHECK(err);

Best regards,
Jørgen

[nick_haman]

That did the trick.  Thank you.  What is the difference between the nrf and nrfx libraries?  All the examples that I've seen reference the nrf drivers.