Hello,I'm confused what the NRF51422 uses for it's digital IO reference. So for example, If I use a 3.0V coin cell battery through its DC/DC converter:1. What voltage does the DC/DC output going to the analog reference pin? 2. What would the chip use for digital reference on VDD? 3V is obviously not a normal voltage, I would want 1.8V or 3.3V, etc. Is there a way to change this?Thanks,
The best and easiest way to use the ADC is to configure it to use its internal 1.2volt bandgap reference.
Then you configure the prescaler such that the sample voltage falls within 0 to 1.2volts.
No matter how you configure the prescaler the input sample voltage cannot exceed Vdd_nRF.
Gotcha - I did not realize there was a prescaler you can use. Can you forward the documentation on that prescaler? I was having trouble finding it.
Absolutely everything is in the product spec. nRF51 Series Reference Manual.