SAADC voltage calculation formula.

[ParanBada]

Hello,

I'm using the SAADC voltage conversion formula from the Nordic example as follows: 10 bits are used in the example.

By the way I want to change ADC resolution to 12bit or 14bit.
So, as shown in the figure, I calculated using 4096 for 12 bit and 16384 for 14 bit.
However, the voltage is not correct.

I can change the setting to 12bit or 14bit as above in sdk_config.h.

What are the respective calculation formulas when the resolution is 12bit and 14bit?

Best Regards,

SunBae Yim.

[Jørgen Holmefjord]

Hi,

The formula for the voltage input is derived from the Digital output formula. The formula is the same for all resolutions, with different input for the RESOLUTION parameter.

As far as I can see, you formula should be correct, and should work for all the 3 resolutions (given that you use internal reference and gain=1/6). What values are you inputting to ADC_VALUE, and what voltage do you get out of the formula?

Best regards,
Jørgen