Adds HardwareSerial::setRxTimeout()

cores/esp32/HardwareSerial.cpp

@@ -128,7 +128,8 @@ HardwareSerial::HardwareSerial(int uart_nr) :
 _uart_nr(uart_nr), 
 _uart(NULL), 
 _rxBufferSize(256), 
-_onReceiveCB(NULL), 
+_onReceiveCB(NULL),
+_onReceiveTimeout(10),
 _onReceiveErrorCB(NULL),
 _eventTask(NULL)
 #if !CONFIG_DISABLE_HAL_LOCKS
@@ -191,10 +192,27 @@ void HardwareSerial::onReceive(OnReceiveCb function)
     HSERIAL_MUTEX_LOCK();
     // function may be NULL to cancel onReceive() from its respective task 
     _onReceiveCB = function;
+
     // this can be called after Serial.begin(), therefore it shall create the event task
     if (function != NULL && _uart != NULL && _eventTask == NULL) {
-        _createEventTask(this);
+        _createEventTask(this); // Create event task
+    }
+    HSERIAL_MUTEX_UNLOCK();
+}
+
+void HardwareSerial::onReceiveTimeout(uint8_t symbols_timeout)
+{
+    HSERIAL_MUTEX_LOCK();
+
+    if(symbols_timeout == 0) {
+        _onReceiveTimeout = 1; // Never disable timeout
+    }
+    else {
+        _onReceiveTimeout = symbols_timeout;
     }
+
+    if(_uart != NULL) uart_set_rx_timeout(_uart_nr, _onReceiveTimeout); // Set new timeout
+
     HSERIAL_MUTEX_UNLOCK();
 }
 
@@ -210,15 +228,17 @@ void HardwareSerial::_uartEventTask(void *args)
             if(xQueueReceive(uartEventQueue, (void * )&event, (portTickType)portMAX_DELAY)) {
                 switch(event.type) {
                     case UART_DATA:
-                        if(uart->_onReceiveCB && uart->available() > 0) uart->_onReceiveCB();
+                        if(uart->_onReceiveCB && uart->available() > 0  && event.timeout_flag) uart->_onReceiveCB();
                         break;
                     case UART_FIFO_OVF:
                         log_w("UART%d FIFO Overflow. Consider adding Hardware Flow Control to your Application.", uart->_uart_nr);
                         if(uart->_onReceiveErrorCB) uart->_onReceiveErrorCB(UART_FIFO_OVF_ERROR);
+                        xQueueReset(uartEventQueue);
                         break;
                     case UART_BUFFER_FULL:
                         log_w("UART%d Buffer Full. Consider encreasing your buffer size of your Application.", uart->_uart_nr);
                         if(uart->_onReceiveErrorCB) uart->_onReceiveErrorCB(UART_BUFFER_FULL_ERROR);
+                        xQueueReset(uartEventQueue);
                         break;
                     case UART_BREAK:
                         log_w("UART%d RX break.", uart->_uart_nr);
@@ -320,6 +340,12 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
     if (_uart != NULL && (_onReceiveCB != NULL || _onReceiveErrorCB != NULL) && _eventTask == NULL) {
         _createEventTask(this);
     }
+
+    // Set UART RX timeout
+    if (_uart != NULL && _onReceiveCB != NULL) {
+        uart_set_rx_timeout(_uart_nr, _onReceiveTimeout);
+    }
+
     HSERIAL_MUTEX_UNLOCK();
 }
 

cores/esp32/HardwareSerial.h

@@ -73,9 +73,21 @@ class HardwareSerial: public Stream
     HardwareSerial(int uart_nr);
     ~HardwareSerial();
 
-    // onReceive will setup a callback for whenever UART data is received
+    // onReceive will setup a callback for whenever UART data is received and a later timeout occurs (no receiving data after specified time):
+    // param function        is the callback to be called after reception timeout
+
     // it will work as UART Rx interrupt -- Using C++ 11 std::fuction 
     void onReceive(OnReceiveCb function);
+
+    // onReceiveTimeout sets the timeout after which onReceive callback will be called (after receiving data, it waits for this time of UART rx inactivity to call the callback fnc)
+    // param symbols_timeout defines a timeout threshold in uart symbol periods. 
+    //                       Minimum is 1 symbol timeout. Maximum is calculacted automatically by IDF. If set above the maximum, it is ignored and an error is printed on Serial0 (check console).
+    //                       Examples: Maximum for 11 bits symbol is 92 (SERIAL_8N2, SERIAL_8E1, SERIAL_8O1, etc), Maximum for 10 bits symbol is 101 (SERIAL_8N1).
+    //                       For example symbols_timeout=1 defines a timeout equal to transmission time of one symbol (~11 bit) on current baudrate. 
+    //                       For a baudrate of 9600, SERIAL_8N1 (10 bit symbol) and symbols_timeout = 3, the timeout would be 3 / (9600 / 10) = 3.125 ms
+    void onReceiveTimeout(uint8_t symbols_timeout);
+
+    // onReceive will be called on error events (see hardwareSerial_error_t)
     void onReceiveError(OnReceiveErrorCb function);
 
     void begin(unsigned long baud, uint32_t config=SERIAL_8N1, int8_t rxPin=-1, int8_t txPin=-1, bool invert=false, unsigned long timeout_ms = 20000UL, uint8_t rxfifo_full_thrhd = 112);
@@ -138,6 +150,7 @@ class HardwareSerial: public Stream
     uart_t* _uart;
     size_t _rxBufferSize;
     OnReceiveCb _onReceiveCB;
+    uint8_t _onReceiveTimeout;
     OnReceiveErrorCb _onReceiveErrorCB;
     TaskHandle_t _eventTask;