Add Serial.swap

This will be very useful when working on other hardware where the serial pins may or may not be swapped. Default state and swap state defined in pins_arduino.h
Call Serial.swap() or Serial.swap(true) to swap pins, and call Serial.swap(false) to return to the default state

avr/cores/arduino/UART.cpp

@@ -131,7 +131,7 @@ void UartClass::begin(unsigned long baud, uint16_t config)
         this->end();
     }
 
-    // Setup port mux
+    // Setup default port mux
     PORTMUX.USARTROUTEA |= _uart_mux;
 
     int32_t baud_setting = 0;
@@ -173,6 +173,43 @@ void UartClass::begin(unsigned long baud, uint16_t config)
     SREG = oldSREG;
 }
 
+void UartClass::swap(uint8_t shouldSwap)
+{
+  if(shouldSwap == true)
+  {
+    // Let PORTMUX pont to alternative UART pins
+    if(_uart_mux_swap > 0)
+      PORTMUX.USARTROUTEA |= _uart_mux;
+    else
+      PORTMUX.USARTROUTEA &= ~_uart_mux;
+
+    // Set pin state for alternative UART pins
+    pinMode(_hwserial_rx_pin_swap, INPUT_PULLUP);
+    digitalWrite(_hwserial_tx_pin_swap, HIGH);
+    pinMode(_hwserial_tx_pin_swap, OUTPUT);
+
+    // Set previous pins to high Z
+    pinMode(_hwserial_rx_pin, INPUT);
+    pinMode(_hwserial_tx_pin, INPUT);
+  }
+  else //if(shouldSwap == false)
+  {
+    if(_uart_mux > 0)
+      PORTMUX.USARTROUTEA |= _uart_mux;
+    else
+      PORTMUX.USARTROUTEA &= ~_uart_mux;
+
+    // Set pin state for default UART pins
+    pinMode(_hwserial_rx_pin, INPUT_PULLUP);
+    digitalWrite(_hwserial_tx_pin, HIGH);
+    pinMode(_hwserial_tx_pin, OUTPUT);
+
+    // Set previous pins to high Z
+    pinMode(_hwserial_rx_pin_swap, INPUT);
+    pinMode(_hwserial_tx_pin_swap, INPUT);
+  }
+}
+
 void UartClass::end()
 {
     // wait for transmission of outgoing data

avr/cores/arduino/UART.h

@@ -127,8 +127,11 @@ class UartClass : public HardwareSerial
 
     volatile uint8_t const _hwserial_rx_pin;
     volatile uint8_t const _hwserial_tx_pin;
+    volatile uint8_t const _hwserial_rx_pin_swap;
+    volatile uint8_t const _hwserial_tx_pin_swap;
 
     volatile uint8_t const _uart_mux;
+    volatile uint8_t const _uart_mux_swap;
 
     // Has any byte been written to the UART since begin()
     bool _written;
@@ -149,9 +152,10 @@ class UartClass : public HardwareSerial
     unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE];
 
   public:
-    inline UartClass(volatile USART_t *hwserial_module, uint8_t hwserial_rx_pin, uint8_t hwserial_tx_pin, uint8_t dre_vect_num, uint8_t uart_mux);
+    inline UartClass(volatile USART_t *hwserial_module, uint8_t hwserial_rx_pin, uint8_t hwserial_tx_pin, uint8_t hwserial_rx_pin_swap, uint8_t hwserial_tx_pin_swap, uint8_t dre_vect_num, uint8_t uart_mux, uint8_t uart_mux_swap);
     void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }
     void begin(unsigned long, uint16_t);
+    void swap(uint8_t shouldSwap = true);
     void end();
     virtual int available(void);
     virtual int peek(void);

avr/cores/arduino/UART0.cpp

@@ -55,7 +55,7 @@ ISR(HWSERIAL0_DRE_VECTOR)
 #endif
 
 #if defined(HWSERIAL0)
-  UartClass Serial(HWSERIAL0, PIN_WIRE_HWSERIAL0_RX, PIN_WIRE_HWSERIAL0_TX, HWSERIAL0_DRE_VECTOR_NUM, HWSERIAL0_MUX);
+  UartClass Serial(HWSERIAL0, PIN_WIRE_HWSERIAL0_RX, PIN_WIRE_HWSERIAL0_TX, PIN_WIRE_HWSERIAL0_RX_PINSWAP, PIN_WIRE_HWSERIAL0_TX_PINSWAP, HWSERIAL0_DRE_VECTOR_NUM, HWSERIAL0_MUX_DEFAULT, HWSERIAL0_MUX_PINSWAP);
 #endif
 
 // Function that can be weakly referenced by serialEventRun to prevent

avr/cores/arduino/UART1.cpp

@@ -55,7 +55,7 @@ ISR(HWSERIAL1_DRE_VECTOR)
 #endif
 
 #if defined(HWSERIAL1)
-  UartClass Serial1(HWSERIAL1, PIN_WIRE_HWSERIAL1_RX, PIN_WIRE_HWSERIAL1_TX, HWSERIAL1_DRE_VECTOR_NUM, HWSERIAL1_MUX);
+  UartClass Serial1(HWSERIAL1, PIN_WIRE_HWSERIAL1_RX, PIN_WIRE_HWSERIAL1_TX, PIN_WIRE_HWSERIAL1_RX_PINSWAP, PIN_WIRE_HWSERIAL1_TX_PINSWAP, HWSERIAL1_DRE_VECTOR_NUM, HWSERIAL1_MUX_DEFAULT, HWSERIAL1_MUX_PINSWAP);
 #endif
 
 // Function that can be weakly referenced by serialEventRun to prevent

avr/cores/arduino/UART2.cpp

@@ -55,7 +55,7 @@ ISR(HWSERIAL2_DRE_VECTOR)
 #endif
 
 #if defined(HWSERIAL2)
-  UartClass Serial2(HWSERIAL2, PIN_WIRE_HWSERIAL2_RX, PIN_WIRE_HWSERIAL2_TX, HWSERIAL2_DRE_VECTOR_NUM, HWSERIAL2_MUX);
+  UartClass Serial2(HWSERIAL2, PIN_WIRE_HWSERIAL2_RX, PIN_WIRE_HWSERIAL2_TX, PIN_WIRE_HWSERIAL2_RX_PINSWAP, PIN_WIRE_HWSERIAL2_TX_PINSWAP, HWSERIAL2_DRE_VECTOR_NUM, HWSERIAL2_MUX_DEFAULT, HWSERIAL2_MUX_PINSWAP);
 #endif
 
 // Function that can be weakly referenced by serialEventRun to prevent

avr/cores/arduino/UART3.cpp

@@ -55,7 +55,7 @@ ISR(HWSERIAL3_DRE_VECTOR)
 #endif
 
 #if defined(HWSERIAL3)
-  UartClass Serial3(HWSERIAL3, PIN_WIRE_HWSERIAL3_RX, PIN_WIRE_HWSERIAL3_TX, HWSERIAL3_DRE_VECTOR_NUM, HWSERIAL3_MUX);
+  UartClass Serial3(HWSERIAL3, PIN_WIRE_HWSERIAL3_RX, PIN_WIRE_HWSERIAL3_TX, PIN_WIRE_HWSERIAL3_RX_PINSWAP, PIN_WIRE_HWSERIAL3_TX_PINSWAP, HWSERIAL3_DRE_VECTOR_NUM, HWSERIAL3_MUX_DEFAULT, HWSERIAL3_MUX_PINSWAP);
 #endif
 
 // Function that can be weakly referenced by serialEventRun to prevent

avr/cores/arduino/UART_private.h

@@ -33,12 +33,18 @@ UartClass::UartClass(
   volatile USART_t *hwserial_module,
   volatile uint8_t hwserial_rx_pin,
   volatile uint8_t hwserial_tx_pin,
+  volatile uint8_t hwserial_rx_pin_swap,
+  volatile uint8_t hwserial_tx_pin_swap,
   volatile uint8_t hwserial_dre_interrupt_vect_num,
-  volatile uint8_t uart_mux) :
+  volatile uint8_t uart_mux,
+  volatile uint8_t uart_mux_swap) :
     _hwserial_module(hwserial_module),
     _hwserial_rx_pin(hwserial_rx_pin),
     _hwserial_tx_pin(hwserial_tx_pin),
+    _hwserial_rx_pin_swap(hwserial_rx_pin_swap),
+    _hwserial_tx_pin_swap(hwserial_tx_pin_swap),
     _uart_mux(uart_mux),
+    _uart_mux_swap(uart_mux_swap),
     _rx_buffer_head(0), _rx_buffer_tail(0),
     _tx_buffer_head(0), _tx_buffer_tail(0),
     _hwserial_dre_interrupt_vect_num(hwserial_dre_interrupt_vect_num),

avr/variants/uno_wifi/pins_arduino.h

@@ -26,6 +26,9 @@
 #include <avr/pgmspace.h>
 #include "timers.h"
 
+#define UNO_WIFI_REV2_PINOUT
+#define UNO2018_PINOUT
+
 #define NUM_DIGITAL_PINS            20 // (14 on digital headers + 6 on analog headers)
 #define NUM_ANALOG_INPUTS           6
 #define NUM_RESERVED_PINS           6  // (TOSC1/2, VREF, RESET, DEBUG USART Rx/Tx)
@@ -65,9 +68,12 @@ static const uint8_t SCL = PIN_WIRE_SCL;
 #define HWSERIAL1_DRE_VECTOR (USART1_DRE_vect)
 #define HWSERIAL1_DRE_VECTOR_NUM (USART1_DRE_vect_num)
 #define HWSERIAL1_RXC_VECTOR (USART1_RXC_vect)
-#define HWSERIAL1_MUX (PORTMUX_USART1_ALT1_gc)
+#define HWSERIAL1_MUX_DEFAULT (PORTMUX_USART1_ALT1_gc)
+#define HWSERIAL1_MUX_PINSWAP (PORTMUX_USART1_DEFAULT_gc)
 #define PIN_WIRE_HWSERIAL1_RX (0)
 #define PIN_WIRE_HWSERIAL1_TX (1)
+#define PIN_WIRE_HWSERIAL1_RX_PINSWAP (33)
+#define PIN_WIRE_HWSERIAL1_TX_PINSWAP (32)
 
 // Uno2 Debug USART (not available on headers, only via the EDGB virtual COM port)
 // USART3 on mega4809 (alternative pins)
@@ -76,9 +82,12 @@ static const uint8_t SCL = PIN_WIRE_SCL;
 #define HWSERIAL0_DRE_VECTOR (USART3_DRE_vect)
 #define HWSERIAL0_DRE_VECTOR_NUM (USART3_DRE_vect_num)
 #define HWSERIAL0_RXC_VECTOR (USART3_RXC_vect)
-#define HWSERIAL0_MUX (PORTMUX_USART3_ALT1_gc)
+#define HWSERIAL0_MUX_DEFAULT (PORTMUX_USART3_ALT1_gc)
+#define HWSERIAL0_MUX_PINSWAP (PORTMUX_USART3_DEFAULT_gc)
 #define PIN_WIRE_HWSERIAL0_RX (26)
 #define PIN_WIRE_HWSERIAL0_TX (27)
+#define PIN_WIRE_HWSERIAL0_RX_PINSWAP (10)
+#define PIN_WIRE_HWSERIAL0_TX_PINSWAP (9)
 
 // Uno2 Spare USART available on testpoints
 // USART0 on mega4809 (alternative pins)
@@ -87,11 +96,14 @@ static const uint8_t SCL = PIN_WIRE_SCL;
 #define HWSERIAL2_DRE_VECTOR (USART0_DRE_vect)
 #define HWSERIAL2_DRE_VECTOR_NUM (USART0_DRE_vect_num)
 #define HWSERIAL2_RXC_VECTOR (USART0_RXC_vect)
-#define HWSERIAL2_MUX (PORTMUX_USART0_ALT1_gc)
+#define HWSERIAL2_MUX_DEFAULT (PORTMUX_USART0_ALT1_gc)
+#define HWSERIAL2_MUX_PINSWAP (PORTMUX_USART0_DEFAULT_gc)
 #define PIN_WIRE_HWSERIAL2_RX (23)
 #define PIN_WIRE_HWSERIAL2_TX (24)
+#define PIN_WIRE_HWSERIAL2_RX_PINSWAP (7)
+#define PIN_WIRE_HWSERIAL2_TX_PINSWAP (2)
 
-#define HWSERIAL3_MUX (PORTMUX_USART2_NONE_gc)
+#define HWSERIAL3_MUX_DEFAULT (PORTMUX_USART2_NONE_gc)
 #define TWI_MUX (PORTMUX_TWI0_DEFAULT_gc) //PORTMUX_TWI0_ALT1_gc
 
 #define MUX_SPI (SPI_MUX)