Either I'm not seeing it, or Microchip doesn't specify it, but I have a
question that perhaps somebody in-the-know can answer (maybe by experience).


I need to get an accurate measurement of voltage which may range from 30V
down to about 3V.  What I was thinking of doing was using a resistor ladder
with multiple taps going to the various ADC inputs on the PIC.  I would
start my measurements on the greatest division (ANx in the picture below)
and if the input voltage was sufficiently low that I could use the next
higher division (ANn-1), I would do that, repeating until I had the
smallest V/div on the ADC (best resolution).

Question is, do the ADC inputs have diode protection like the digital
inputs?  Will my scheme work properly?

Concept:

       3-30V+
         |
         |
         R1
         |
         +-----> AN0 input
         |
         |
         R2
         |
         |
         +-----> AN1 input
         |
         |
         R3
         |
         |
         +-----> AN2 input
         |
         |
         etc.
         |
         |
         +-----> ANx input
         |
         |
        -----
         GND

Thanks.

Andy

==================================================================
Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
==================================================================