ADC

[wallarug]

There is an issue with syncADC() as it is not used in the Arduino. So maybe we can exclude it from SeeSaw too?

The function adc_trigger() is also an issue as you can have multiple ADCs on SAMD51. This will not work. It is only used in source/AOADC.cpp so maybe we need to seek guidance on this.

From Arduino wiring_analog.c

#if defined(__SAMD51__)
  Adc *adc;
  if(g_APinDescription[pin].ulPinAttribute & PIN_ATTR_ANALOG) adc = ADC0;
  else if(g_APinDescription[pin].ulPinAttribute & PIN_ATTR_ANALOG_ALT) adc = ADC1;
  else return 0;

  while( adc->SYNCBUSY.reg & ADC_SYNCBUSY_INPUTCTRL ); //wait for sync
  adc->INPUTCTRL.bit.MUXPOS = g_APinDescription[pin].ulADCChannelNumber; // Selection for the positive ADC input

  // Control A
  /*
   * Bit 1 ENABLE: Enable
   *   0: The ADC is disabled.
   *   1: The ADC is enabled.
   * Due to synchronization, there is a delay from writing CTRLA.ENABLE until the peripheral is enabled/disabled. The
   * value written to CTRL.ENABLE will read back immediately and the Synchronization Busy bit in the Status register
   * (STATUS.SYNCBUSY) will be set. STATUS.SYNCBUSY will be cleared when the operation is complete.
   *
   * Before enabling the ADC, the asynchronous clock source must be selected and enabled, and the ADC reference must be
   * configured. The first conversion after the reference is changed must not be used.
   */
  while( adc->SYNCBUSY.reg & ADC_SYNCBUSY_ENABLE ); //wait for sync
  adc->CTRLA.bit.ENABLE = 0x01;             // Enable ADC

  // Start conversion
  while( adc->SYNCBUSY.reg & ADC_SYNCBUSY_ENABLE ); //wait for sync

  adc->SWTRIG.bit.START = 1;

  // Clear the Data Ready flag
  adc->INTFLAG.reg = ADC_INTFLAG_RESRDY;

  // Start conversion again, since The first conversion after the reference is changed must not be used.
  adc->SWTRIG.bit.START = 1;

  // Store the value
  while (adc->INTFLAG.bit.RESRDY == 0);   // Waiting for conversion to complete
  valueRead = adc->RESULT.reg;

  while( adc->SYNCBUSY.reg & ADC_SYNCBUSY_ENABLE ); //wait for sync
  adc->CTRLA.bit.ENABLE = 0x00;             // Disable ADC
  while( adc->SYNCBUSY.reg & ADC_SYNCBUSY_ENABLE ); //wait for sync

[wallarug]

Files impacted:

bsp/bsp_adc.h defines syncADC() and adc_trigger()

bsp/bsp_adc.cpp calls syncADC() -- only file

source/AOADC.cpp calls adc_trigger() -- only file

[wallarug]

The solution for now is to disable ADC1 completely as on the SAMD51J there is only a small number of ADC1s available. With most of the ADC1 pins able to use an ADC0 equiv.