How to set ADC_PRE_SCALING_COMPENSATION) in the program.

[chandana k v]

Hi,

I am using NRF52840 DK board. I am using SAADC example program for reading the voltage and SDK 15.3.0 Version.

We have connected the sensor to the adc analog output pin 0 and we are able to read the voltage and now the doubt is how do i need to convert the adc value into voltage.

So when i searched i got this formula 

Result = ((ADC_VALUE) * ADC_REF_VOLTAGE_IN_VOLTS) / ADC_RES10_BIT) * ADC_PRE_SCALING_COMPENSATION)

Now my doubt is how do i set the ADC_PRE_SCALING_COMPENSATION in the program i have searched in the program to set this value but i didn't get in the program 

Could you please  tell me how to set this value in the program and what value do i need to use in order to get the voltage

Please help me.

[Karl Ylvisaker]

Hello,

Which example are you using exactly, the SAADC peripheral example? I do not see the ADC_PRE_SCALING_COMPENSATION used here.

ADC_PRE_SCALING_COMPENSATION was used in examples previously to compensate for the influence of the chosen gain level for the SAADC. To avoid confusion you should instead calculate the voltage level using the formula from the SAADC peripheral documentation.

Best regards,
Karl