Adds additional notes and corrects others on the SAMD21 Qwiic Micro

Author: edspark

sparkfun/samd/variants/SparkFun_Qwiic_Micro/variant.cpp

@@ -51,8 +51,8 @@ const PinDescription g_APinDescription[] =
 
   // 16/17 - RX/TX 
   // --------------------
-  { PORTA, 23, PIO_SERCOM, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM4_CH1, TC4_CH1, EXTERNAL_INT_7 },       // RX/D17
-  { PORTA, 22, PIO_SERCOM, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM4_CH0, TC4_CH0, EXTERNAL_INT_6 },       // TX/D16
+  { PORTA, 23, PIO_SERCOM, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM4_CH1, TC4_CH1, EXTERNAL_INT_7 },       // RX/D16 
+  { PORTA, 22, PIO_SERCOM, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM4_CH0, TC4_CH0, EXTERNAL_INT_6 },       // TX/D17
 
   // 18-21 - Flash SPI
   // --------------------
@@ -73,7 +73,7 @@ const PinDescription g_APinDescription[] =
   { PORTA,  5, PIO_ANALOG, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), ADC_Channel5, PWM0_CH1, TCC0_CH1, EXTERNAL_INT_5 },        // A2/D3
   { PORTA,  7, PIO_ANALOG, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), ADC_Channel7, PWM1_CH1, TCC1_CH1, EXTERNAL_INT_7 },        // A3/D4
   { PORTA, 10, PIO_ANALOG, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), ADC_Channel18, PWM1_CH0, TCC1_CH0, EXTERNAL_INT_10 },      // A4/D13
-  { PORTA,  4, PIO_ANALOG, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), ADC_Channel4, PWM0_CH0, TCC0_CH0, EXTERNAL_INT_4 },        // A5/D6
+  { PORTA,  4, PIO_ANALOG, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), ADC_Channel4, PWM0_CH0, TCC0_CH0, EXTERNAL_INT_4 },        // A5/D7
 
   // 30..32 - USB
   // --------------------

sparkfun/samd/variants/SparkFun_Qwiic_Micro/variant.h

@@ -110,9 +110,9 @@ static const uint8_t DAC0 = PIN_DAC0;
  */
 
 // Serial
-#define PIN_SERIAL_TX       (16ul)
-#define PIN_SERIAL_RX       (17ul)
-#define PAD_SERIAL_TX       (UART_TX_PAD_0)
+#define PIN_SERIAL_TX       (17ul) // Transmit can only be on PAD0 or PAD2
+#define PIN_SERIAL_RX       (16ul) // Receive can be on any pins. 
+#define PAD_SERIAL_TX       (UART_TX_PAD_0) 
 #define PAD_SERIAL_RX       (SERCOM_RX_PAD_1)
 
 /*