nRF52832 SAADC 14-bit with 0 oversampling

[SeanK]

I'm using the nRF52832, and taking ADC measurements, with 14 bit resolution and with Oversampling disabled. The nRF52832 Product Specification mentions the saadc can be configured with "8/10/12-bit resolution, 14-bit resolution with oversampling";

My measurements are coming back in a 14-bit format. Is oversampling occurring even though my sdk_config.h has the line "#define SAADC_CONFIG_OVERSAMPLE 0"? Does the nRF52832 actually have a 14-bit adc?

If oversampling is occuring, what's the nature of it? I have acquisition time set to 10uS. How many additional samples are taken, and how much time are they taking?

When i'm calculating quantization noise, should i assume 14-bits or 12-bits?

Thank you!

[Podrucky]

I am wondering how to get 14 bit ADC measurement working.  Could you post your code?

[SeanK]

The saadc example provided in the SDK is a good place to start to get ADC measurements working on the dev board. Edit the file sdk_config.h; Changing SAADC_CONFIG_RESOLUTION to 3 will achieve 14 bit responses

// <o> SAADC_CONFIG_RESOLUTION  - Resolution
 
// <0=> 8 bit 
// <1=> 10 bit 
// <2=> 12 bit 
// <3=> 14 bit 

#ifndef SAADC_CONFIG_RESOLUTION
#define SAADC_CONFIG_RESOLUTION 3
#endif