Proximity Example SAADC reading

[Nicholas_Nuti]

Hello,

So I assume VDD is from USB or the battery depending on whether USB is there or not. So, when the SAADC outputs ~3.258 V (in low power mode) that's fairly correct.... but when I disconnect the usb and run on battery only I get the same voltage. I got the battery reading part of my program from proximity example. Is this SAADC output directly from the battery or am I mistaken? From what I've read, the SAADC terminal VDD will come from whatever the current input source is.

Oh, also when I turn low power mode off on the SAADC I get a reading of around 3.6V coming from the USB which... I'm sure is incorrect.

Please help if you can!

[ketiljo]

Is this measured on the DK? The ADC reads the voltage on the VDD pin. VBUS will be regulated and fed to VDD via REG0. You can find a description of the power supply here> infocenter.nordicsemi.com/.../hw_power_supply.html

[Nicholas_Nuti]

Yes, this is measured on the DK. I'm also sending voltage values measured by the SAADC over bluetooth. The voltages sent over bluetooth while running on the battery are wrong. Is there something I need to add to the proximity example to get accurate battery input voltages?

[ketiljo]

Try connecting the battery directly and make sure you setup the ADC to measure VDD 

[Nicholas_Nuti]

I currently have it measuring the INPUT_VDD. I have directly measured the battery @ 3.0V.

[ketiljo]

Is it still incorrect of you connect the battery directly as in the link?