[UART] Adds SerialUART::getActualBaud() (#3225)

Author: ngist

cores/rp2040/SerialUART.cpp

@@ -239,7 +239,7 @@ void SerialUART::begin(unsigned long baud, uint16_t config) {
         gpio_set_inover(_cts, _invertControl ? 1 : 0);
     }
 
-    uart_init(_uart, baud);
+    _actualBaud = uart_init(_uart, baud);
     int bits, stop;
     uart_parity_t parity;
     switch (config & SERIAL_PARITY_MASK) {

cores/rp2040/SerialUART.h

@@ -93,13 +93,19 @@ class SerialUART : public arduino::HardwareSerial {
     // on read)
     bool getBreakReceived();
 
+    // Returns the baud rate the uart is actually operating at vs the desired baud rate specified to begin()
+    int getActualBaud() {
+        return _running ? _actualBaud : 0;
+    }
+
 private:
     bool _running = false;
     uart_inst_t *_uart;
     pin_size_t _tx, _rx;
     pin_size_t _rts, _cts;
     gpio_function_t _fcnTx, _fcnRx, _fcnRts, _fcnCts;
     int _baud;
+    int _actualBaud;
     mutex_t _mutex;
     bool _polling = false;
     bool _overflow;