7 Replies Latest reply on Jul 9, 2015 3:23 PM by CMata_Intel

    Non-linear analog reading when switching to 3.3V operation on Edison with Arduino breakout

    aneedles

      Hi,

        I am getting non-linear analog readings when using 3.3V operation on the Edison with Arduino breakout board and Grove base shield.

       

      The analog readings work fine with the standard 5.0V setup, and the graph below (A3 vs 50Hz time sample) would show smooth transitions. Any ideas why I would get what you see below when switching to 3.3V?  I still get full range, but the data is noisy and has skipped regions - such as between ~125 and ~270.

       

      The only configuration changes made were:

      Arduino breakout: J9 changed to connect pins 2 and 3.

      Grove base shield v1.3: moved 5V/3.3V switch to the 3.3V position

       

       

      Graph showing 3.3V operation of A3:

      poorAnalog.jpg

       

      Thanks,

          Aaron