fixes setPins and begin to keep rx/tx unmodified

Author: SuGlider

cores/esp32/HardwareSerial.cpp

@@ -114,37 +114,46 @@ void serialEventRun(void)
 }
 #endif
 
-
 HardwareSerial::HardwareSerial(int uart_nr) : _uart_nr(uart_nr), _uart(NULL), _rxBufferSize(256) {}
 
+enum { UART_NUM_0, UART_NUM_1, UART_NUM_2 };
+
 void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, int8_t txPin, bool invert, unsigned long timeout_ms, uint8_t rxfifo_full_thrhd)
 {
     if(0 > _uart_nr || _uart_nr >= SOC_UART_NUM) {
         log_e("Serial number is invalid, please use numers from 0 to %u", SOC_UART_NUM - 1);
         return;
     }
+
+    // First Time or after end() --> set default Pins
+    if (!uartIsDriverInstalled(_uart)) {
+        switch (_uart_nr) {
+            case UART_NUM_0:
+                rxPin = rxPin < 0 ? SOC_RX0 : rxPin;
+                txPin = txPin < 0 ? SOC_TX0 : txPin;
+            break;
+#if SOC_UART_NUM > 1                   // may save some flash bytes...
+            case UART_NUM_1:
+                rxPin = rxPin < 0 ? RX1 : rxPin;
+                txPin = txPin < 0 ? TX1 : txPin;
+            break;
+#endif
+#if SOC_UART_NUM > 2                   // may save some flash bytes...
+            case UART_NUM_2:
+                rxPin = rxPin < 0 ? RX2 : rxPin;
+                txPin = txPin < 0 ? TX2 : txPin;
+            break;
+#endif
+        }
+    }
+
     if(_uart) {
         // in this case it is a begin() over a previous begin() - maybe to change baud rate
         // thus do not disable debug output
         end(false);
     }
-    if(_uart_nr == 0 && rxPin < 0 && txPin < 0) {
-        rxPin = SOC_RX0;
-        txPin = SOC_TX0;
-    }
-#if SOC_UART_NUM > 1
-    if(_uart_nr == 1 && rxPin < 0 && txPin < 0) {
-        rxPin = RX1;
-        txPin = TX1;
-    }
-#endif
-#if SOC_UART_NUM > 2
-    if(_uart_nr == 2 && rxPin < 0 && txPin < 0) {
-        rxPin = RX2;
-        txPin = TX2;
-    }
-#endif
 
+    // IDF UART driver keeps Pin setting on restarting. Negative Pin number will keep it unmodified.
     _uart = uartBegin(_uart_nr, baud ? baud : 9600, config, rxPin, txPin, _rxBufferSize, invert, rxfifo_full_thrhd);
     if (!baud) {
         // using baud rate as zero, forces it to try to detect the current baud rate in place
@@ -159,7 +168,7 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
 
         if(detectedBaudRate) {
             delay(100); // Give some time...
-            _uart = uartBegin(_uart_nr, detectedBaudRate, config, rxPin, txPin, _rxBufferSize, invert, rxfifo_full_thrhd);
+            _uart = uartBegin(_uart_nr, detectedBaudRate, config,  rxPin, txPin, _rxBufferSize, invert, rxfifo_full_thrhd);
         } else {
             log_e("Could not detect baudrate. Serial data at the port must be present within the timeout for detection to be possible");
             _uart = NULL;
@@ -280,9 +289,16 @@ void HardwareSerial::setRxInvert(bool invert)
     uartSetRxInvert(_uart, invert);
 }
 
-void HardwareSerial::setPins(uint8_t rxPin, uint8_t txPin)
+// negative Pin value will keep it unmodified
+void HardwareSerial::setPins(int8_t rxPin, int8_t txPin)
+{
+    uartSetPins(_uart, rxPin, txPin, -1, -1);
+}
+
+// negative Pin value will keep it unmodified
+void HardwareSerial::setAllPins(int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin)
 {
-    uartSetPins(_uart, rxPin, txPin);
+    uartSetPins(_uart, rxPin, txPin, ctsPin, rtsPin);
 }
 
 size_t HardwareSerial::setRxBufferSize(size_t new_size) {

cores/esp32/HardwareSerial.h

@@ -107,7 +107,12 @@ class HardwareSerial: public Stream
     void setDebugOutput(bool);
 
     void setRxInvert(bool);
-    void setPins(uint8_t rxPin, uint8_t txPin);
+
+    // Negative Pin Number will keep it unmodified, thus this function can set individual pins
+    // SetPins shall be called after Serial begin()
+    void setPins(int8_t rxPin, int8_t txPin);
+    void setAllPins(int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin);
+    
     size_t setRxBufferSize(size_t new_size);
 
 protected:

cores/esp32/esp32-hal-uart.c

@@ -155,15 +155,17 @@ bool uartIsDriverInstalled(uart_t* uart)
     return false;
 }
 
-void uartSetPins(uart_t* uart, uint8_t rxPin, uint8_t txPin)
+// Valid pin UART_PIN_NO_CHANGE is defined to (-1)
+// Negative Pin Number will keep it unmodified, thus this function can set individual pins
+void uartSetPins(uart_t* uart, int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin)
 {
-    if(uart == NULL || rxPin >= SOC_GPIO_PIN_COUNT || txPin >= SOC_GPIO_PIN_COUNT) {
+    if(uart == NULL) {
         return;
     }
     UART_MUTEX_LOCK();
-    ESP_ERROR_CHECK(uart_set_pin(uart->num, txPin, rxPin, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE)); 
-    UART_MUTEX_UNLOCK();
-    
+    // IDF uart_set_pin() will issue necessary Error Message and take care of all GPIO Number validation.
+    uart_set_pin(uart->num, txPin, rxPin, ctsPin, rtsPin); 
+    UART_MUTEX_UNLOCK();  
 }
 
 
@@ -173,10 +175,6 @@ uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rx
         return NULL;
     }
 
-    if(rxPin == -1 && txPin == -1) {
-        return NULL;
-    }
-
     uart_t* uart = &_uart_bus_array[uart_nr];
 
     if (uart_is_driver_installed(uart_nr)) {

cores/esp32/esp32-hal-uart.h

@@ -76,7 +76,9 @@ void uartSetDebug(uart_t* uart);
 int uartGetDebug();
 
 bool uartIsDriverInstalled(uart_t* uart);
-void uartSetPins(uart_t* uart, uint8_t rxPin, uint8_t txPin);
+
+// Negative Pin Number will keep it unmodified, thus this function can set individual pins
+void uartSetPins(uart_t* uart, int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin);
 
 void uartStartDetectBaudrate(uart_t *uart);
 unsigned long uartDetectBaudrate(uart_t *uart);