Good find. I have a project at the moment where this would be useful. The data sheet is a little unclear as to how this can be used, it appears that the only place that the Fixed Vref goes is to the ADC input - is this correct? I'll probably get time tomorrow to try this but just thought I'd ask (it's midnight here). The reason I ask is because I'm using the comparators with the ladder Vref and the diagrams in the data sheet suggest that this would still work to measure Vdd.
Thanks for the AN, that will come in useful tomorrow. It doesn't however answer my question, can you have both the ladder Vref and the Fixed Vref at the same time. I.E ladder to comparator inputs and fixed to ADC input.
The fixed Vref can be used as the reference to for the comparators too. CVref and the fixed Vref are multiplexed (see bits C1Rsel and C2Rsel).
Also, CVref can be selected as the input of the A/D converter according to the datasheet (ADCON0, CHS0/3).
I haven't used both at the same time but I agree with you, the diagrams in the datasheet suggest that it's possible.
Pommie said:
The reason I ask is because I'm using the comparators with the ladder Vref and the diagrams in the data sheet suggest that this would still work to measure Vdd.