I'm using a PIC16F883 and need to do analog conversion on a 48V battery pack.
I thought that I could use the +Vref pin of the mcu connected to +12v, and then a 36V Zener on the 48V pack to give me a range of 48V-36V=12V, so that it could read the battery pack from 36-48V.
However, I'm having problems. I assumed that the +12V to the +Vref pin would work, however because of some weird things happening, I'm beginning to fear that the +Vref cannot be more than Vcc, which is 3V in my case... Is that true?
If that is true, How do I measure a 12V swing from a 48V pack?
I'm stuck and on a deadline! Help please!
I thought that I could use the +Vref pin of the mcu connected to +12v, and then a 36V Zener on the 48V pack to give me a range of 48V-36V=12V, so that it could read the battery pack from 36-48V.
However, I'm having problems. I assumed that the +12V to the +Vref pin would work, however because of some weird things happening, I'm beginning to fear that the +Vref cannot be more than Vcc, which is 3V in my case... Is that true?
If that is true, How do I measure a 12V swing from a 48V pack?
I'm stuck and on a deadline! Help please!