Add RTS/CTS to Arduino Nano Connect Serial2(NINA) (#525)

Fixes #524

Author: earlephilhower

README.md

@@ -18,7 +18,7 @@ See https://arduino-pico.readthedocs.io/en/latest/ along with the examples for m
 * Adafruit QTPy RP2040
 * Adafruit STEMMA Friend RP2040
 * Adafruit Trinkey RP2040 QT
-* Arduino Nano RP2040 Connect (preliminary)
+* Arduino Nano RP2040 Connect
 * Cytron Maker Pi RP2040
 * Cytron Maker Nano RP2040
 * DeRuiLab FlyBoard2040 Core

cores/rp2040/SerialUART.cpp

@@ -114,12 +114,12 @@ bool SerialUART::setFIFOSize(size_t size) {
     return true;
 }
 
-SerialUART::SerialUART(uart_inst_t *uart, pin_size_t tx, pin_size_t rx) {
+SerialUART::SerialUART(uart_inst_t *uart, pin_size_t tx, pin_size_t rx, pin_size_t rts, pin_size_t cts) {
     _uart = uart;
     _tx = tx;
     _rx = rx;
-    _rts = UART_PIN_NOT_DEFINED;
-    _cts = UART_PIN_NOT_DEFINED;
+    _rts = rts;
+    _cts = cts;
     mutex_init(&_mutex);
     mutex_init(&_fifoMutex);
 }
@@ -339,8 +339,17 @@ SerialUART::operator bool() {
     return _running;
 }
 
+#if defined(PIN_SERIAL1_RTS)
+SerialUART Serial1(uart0, PIN_SERIAL1_TX, PIN_SERIAL1_RX, PIN_SERIAL1_RTS, PIN_SERIAL1_CTS);
+#else
 SerialUART Serial1(uart0, PIN_SERIAL1_TX, PIN_SERIAL1_RX);
+#endif
+
+#if defined(PIN_SERIAL2_RTS)
+SerialUART Serial2(uart1, PIN_SERIAL2_TX, PIN_SERIAL2_RX, PIN_SERIAL2_RTS, PIN_SERIAL2_CTS);
+#else
 SerialUART Serial2(uart1, PIN_SERIAL2_TX, PIN_SERIAL2_RX);
+#endif
 
 void arduino::serialEvent1Run(void) {
     if (serialEvent1 && Serial1.available()) {

cores/rp2040/SerialUART.h

@@ -31,7 +31,7 @@ extern "C" typedef struct uart_inst uart_inst_t;
 #define UART_PIN_NOT_DEFINED      (255u)
 class SerialUART : public HardwareSerial {
 public:
-    SerialUART(uart_inst_t *uart, pin_size_t tx, pin_size_t rx);
+    SerialUART(uart_inst_t *uart, pin_size_t tx, pin_size_t rx, pin_size_t rts = UART_PIN_NOT_DEFINED, pin_size_t cts = UART_PIN_NOT_DEFINED);
 
     // Select the pinout.  Call before .begin()
     bool setRX(pin_size_t pin);

variants/arduino_nano_connect/pins_arduino.h

@@ -47,8 +47,10 @@ static const uint8_t A3 = (29u);
 #define PIN_SERIAL1_TX (D1)
 #define PIN_SERIAL1_RX (D0)
 
-#define PIN_SERIAL2_TX (D25)
-#define PIN_SERIAL2_RX (D26)
+#define PIN_SERIAL2_TX  (D25)
+#define PIN_SERIAL2_RX  (D26)
+#define PIN_SERIAL2_CTS (D27)
+#define PIN_SERIAL2_RTS (D28)
 
 // SPI
 #define PIN_SPI0_MISO  (D12)