how to use defined values like DACC_MR

Official Hardware Mega Due
4

I now got the DAC to work via the PDC, still without any need for interrupts.
pity I cannot post > 9500 char, see attachment

lessons learned :

  • when using half-word mode, for some reason the value in TCR and TNCR must be double the actual value.
    in full word mode, stuff works as expected.
  • on the scope, the signal returns to zero (0.7 volts in fact) after each value being output.
    this is strange, and was not the case when writing to the DAC without PDC.
    tweaking the REFRESH parameter shows no difference
  • using Serial.println() messes up the DAC output, apparently the DAC must wait until Serial.println() is done.

Time to go study other datasheets, maybe the other SAM3 datasheets contain more info.

ownDMADACC.ino (5.27 KB)