2 Replies Latest reply on Dec 10, 2019 11:57 PM by OlPe_282281

    DeltaSigma, DMA write into Array and wrong results

    OlPe_282281

      Hi,

       

      the attached project tries to sample a differentiell voltage into an array. Each time a button is pressed these shall be sampled and stored into an array. After aquiring the sample array shall be written out to the UART.

       

      I'm using the Cy8CKit-059 and see useless values even I short cut the inputs and ground them (expecting to see 0V).

       

      ---8<--

      Press Trigger button to sample

      Start sampling

      Dump samples:

      Sample   0: -24576 mV

      Sample   1: -28672 mV

      Sample   2: -28672 mV

      Sample   3: -28672 mV

      Sample   4: -28672 mV

      Sample   5: -28672 mV

      Sample   6: -32768 mV

      Sample   7: -28672 mV

      Sample   8: -24576 mV

      Sample   9: -28672 mV

      Sample  10: -28672 mV

      Sample  11: -28672 mV

      Sample  12: -28672 mV

      Sample  13: -28672 mV

      Sample  14: -28672 mV

      Sample  15: -28672 mV

      Sample  16: -24576 mV

      Sample  17: -24576 mV

      Sample  18: -24576 mV

      Sample  19: -28672 mV

      Sample  20: -28672 mV

      ....

      Sample 188: -24576 mV

      Sample 189: -24576 mV

      Sample 190: -32768 mV

      Sample 191: -32768 mV

      Sample 192: -28672 mV

      Sample 193: -28672 mV

      Sample 194: -28672 mV

      Sample 195: -24576 mV

      Sample 196: -28672 mV

      Sample 197: -28672 mV

      Sample 198: -32768 mV

      Sample 199: -28672 mV

      --- 8<----

       

      I expect to see values between +/- 2048 mV, even not approx. 20V

       

      What's gone wrong here and how can  fix it?

       

      Thanks