4 Replies Latest reply on Jul 3, 2019 12:09 AM by RoyL_01

    SAR ADC Averaging Mode: Possible to create higher resolution results?

    jozhc_4299466

      Hi,

       

      I'm using PSOC4 SAR ADC sequencer block and I don't understand how the two averaging modes (accumulate vs fixed resolution) work.

       

      What I'm trying to do is to oversample a channel 16x and increase the effective number of bits by 2 (from 12-bit to 14-bit). I understand there are assumptions about the white noise distribution but let's assume all those things for this discussion. What I have discovered is that if I use the fixed resolution averaging mode, the result after oversampling 16x is still a 12-bit number. What I would like is to get a 14-bit number to work with after all the accumulate and decimate actions in the ADC block.

       

      I know I can write an ISR to do the accumulate and bit shifting in software but that will oversample all channels.

       

      Is there an elegant solution to what I'm trying to achieve here using the built-in ADC block? I noticed that the averaging mode has an accumulate option. What should I expect from this option? Is the end result already averaged or simply accumulated? What software processing is required to convert the result under accumulate option to the 14-bit number I want?

       

      Thanks in advance,

      John