experiment with a bandgap analog read (not working)

Author: ladyada

cores/arduino/WVariant.h

@@ -57,6 +57,8 @@ typedef enum _EAnalogChannel
   ADC_Channel19=19,
   DAC_Channel0,
   DAC_Channel1,
+  ADC_Channel_Bandgap=0x1B,
+  ADC_Channel_PTAT=0x1C,
 } EAnalogChannel ;
 
 #if defined(__SAMD51__)

variants/pybadge_m4/variant.cpp

@@ -117,6 +117,8 @@ const PinDescription g_APinDescription[]=
   // D51 Speaker enable
   { PORTA, 27, PIO_DIGITAL, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
 
+  // D52 Bandgap input
+  { NOT_A_PORT, PIN_NOT_A_PIN, PIO_NOT_A_PIN, PIN_ATTR_ANALOG, ADC_Channel_PTAT, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
 } ;
 
 const void* g_apTCInstances[TCC_INST_NUM+TC_INST_NUM]={ TCC0, TCC1, TCC2, TCC3, TCC4, TC0, TC1, TC2, TC3, TC4, TC5 } ;

variants/pybadge_m4/variant.h

@@ -98,6 +98,7 @@ extern "C"
 #define PIN_A7               (PIN_A0 + 7)
 #define PIN_A8               (PIN_A0 + 8)
 #define PIN_A9               (PIN_A0 + 9)
+#define PIN_BANDGAP_ADC      52
 
 #define PIN_DAC0             PIN_A0
 #define PIN_DAC1             PIN_A1