Make changes in asf4_conf even though I think in these cases the "peripherals" submodule is running the show. Arduino clocks the DAC at 12MHz but uses the CCTRL setting for clocking < 1.2MHz (100kSPS). A fresh clock (6) is allocated for the new 12MHz clock. This matches the Arduino value, though not the GCLK index. Modify other settings to more closely resemble Arduino. In AudioOut, actually clock the waveform data from the timer we set up for this purpose. This gives good waveforms when setting AnalogOut full-scale in a loop, but the rise/fall of waveforms that come from AudioOut are still erratic. Weirdly, if AudioOut limits its range even slightly (e.g., to 1000..64000) then the erratic Note that this will require https://github.com/adafruit/samd-peripherals/pull/26 to be accepted for the submodule update here to work.