Adds HardwareSerial::setRxTimeout()

cores/esp32/HardwareSerial.cpp

@@ -122,11 +122,13 @@ void serialEventRun(void)
 
 HardwareSerial::HardwareSerial(int uart_nr) : 
 _uart_nr(uart_nr), 
-_uart(NULL), 
+_uart(NULL),
 _rxBufferSize(256),
 _txBufferSize(0), 
 _onReceiveCB(NULL), 
 _onReceiveErrorCB(NULL),
+_onReceiveTimeout(true),
+_rxTimeout(10),
 _eventTask(NULL)
 #if !CONFIG_DISABLE_HAL_LOCKS
     ,_lock(NULL)
@@ -183,18 +185,49 @@ void HardwareSerial::onReceiveError(OnReceiveErrorCb function)
     HSERIAL_MUTEX_UNLOCK();
 }
 
-void HardwareSerial::onReceive(OnReceiveCb function)
+void HardwareSerial::onReceive(OnReceiveCb function, bool onlyOnTimeout)
 {
     HSERIAL_MUTEX_LOCK();
     // function may be NULL to cancel onReceive() from its respective task 
     _onReceiveCB = function;
+    // When Rx timeout is Zero (disabled), there is only one possible option that is callback when FIFO reaches 120 bytes
+    _onReceiveTimeout = _rxTimeout > 0 ? onlyOnTimeout : false;
+
     // 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();
 }
 
+// timout is calculates in time to receive UART symbols at the UART baudrate.
+// the estimation is about 11 bits per symbol (SERIAL_8N1)
+void HardwareSerial::setRxTimeout(uint8_t symbols_timeout)
+{
+    HSERIAL_MUTEX_LOCK();
+
+    // Zero disables timeout, thus, onReceive callback will only be called when RX FIFO reaches 120 bytes
+    // Any non-zero value will activate onReceive callback based on UART baudrate with about 11 bits per symbol 
+    _rxTimeout = symbols_timeout;   
+    if (!symbols_timeout) _onReceiveTimeout = false;  // only when RX timeout is disabled, we also must disable this flag 
+
+    if(_uart != NULL) uart_set_rx_timeout(_uart_nr, _rxTimeout); // Set new timeout
+
+    HSERIAL_MUTEX_UNLOCK();
+}
+
+void HardwareSerial::eventQueueReset()
+{
+    QueueHandle_t uartEventQueue = NULL;
+    if (_uart == NULL) {
+	    return;
+    }
+    uartGetEventQueue(_uart, &uartEventQueue);
+    if (uartEventQueue != NULL) {
+        xQueueReset(uartEventQueue);
+    }
+}
+
 void HardwareSerial::_uartEventTask(void *args)
 {
     HardwareSerial *uart = (HardwareSerial *)args;
@@ -207,14 +240,16 @@ 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 && 
+                            ((uart->_onReceiveTimeout && event.timeout_flag) || !uart->_onReceiveTimeout) ) 
+                                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);
                         break;
                     case UART_BUFFER_FULL:
-                        log_w("UART%d Buffer Full. Consider encreasing your buffer size of your Application.", uart->_uart_nr);
+                        log_w("UART%d Buffer Full. Consider increasing your buffer size of your Application.", uart->_uart_nr);
                         if(uart->_onReceiveErrorCB) uart->_onReceiveErrorCB(UART_BUFFER_FULL_ERROR);
                         break;
                     case UART_BREAK:
@@ -317,6 +352,12 @@ 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) {
+        uart_set_rx_timeout(_uart_nr, _rxTimeout);
+    }
+
     HSERIAL_MUTEX_UNLOCK();
 }
 

cores/esp32/HardwareSerial.h

@@ -73,10 +73,31 @@ class HardwareSerial: public Stream
     HardwareSerial(int uart_nr);
     ~HardwareSerial();
 
-    // onReceive will setup a callback for whenever UART data is received
-    // it will work as UART Rx interrupt -- Using C++ 11 std::fuction 
-    void onReceive(OnReceiveCb function);
+    // setRxTimeout 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. Setting 0 symbol timeout disables the callback call by timeout.
+    //                       Maximum timeout setting 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 setRxTimeout(uint8_t symbols_timeout);
+
+    // onReceive will setup a callback that will be called whenever an UART interruption occurs (UART_INTR_RXFIFO_FULL or UART_INTR_RXFIFO_TOUT)
+    // UART_INTR_RXFIFO_FULL interrupt triggers at UART_FULL_THRESH_DEFAULT bytes received (defined as 120 bytes by default in IDF)
+    // UART_INTR_RXFIFO_TOUT interrupt triggers at UART_TOUT_THRESH_DEFAULT symbols passed without any reception (defined as 10 symbos by default in IDF)
+    // onlyOnTimeout parameter will define how onReceive will behave:
+    // Default: true -- The callback will only be called when RX Timeout happens. 
+    //                  Whole stream of bytes will be ready for being read on the callback function at once.
+    //                  This option may lead to Rx Overflow depending on the Rx Buffer Size and number of bytes received in the streaming
+    //         false -- The callback will be called when FIFO reaches 120 bytes and also on RX Timeout.
+    //                  The stream of incommig bytes will be "split" into blocks of 120 bytes on each callback.
+    //                  This option avoid any sort of Rx Overflow, but leaves the UART packet reassembling work to the Application.
+    void onReceive(OnReceiveCb function, bool onlyOnTimeout = true);
+
+    // onReceive will be called on error events (see hardwareSerial_error_t)
     void onReceiveError(OnReceiveErrorCb function);
+
+    // eventQueueReset clears all events in the queue (the events that trigger onReceive and onReceiveError) - maybe usefull in some use cases
+    void eventQueueReset();
 
     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);
     void end(bool fullyTerminate = true);
@@ -140,6 +161,9 @@ class HardwareSerial: public Stream
     size_t _rxBufferSize;
     size_t _txBufferSize;
     OnReceiveCb _onReceiveCB;
+    // _onReceive and _rxTimeout have be consistent when timeout is disabled
+    bool _onReceiveTimeout;
+    uint8_t _rxTimeout;
     OnReceiveErrorCb _onReceiveErrorCB;
     TaskHandle_t _eventTask;