fix modbus serial event misalingnment

docs/conf_common.py

@@ -1,3 +1,14 @@
+# -*- coding: utf-8 -*-
+#
+# Common (non-language-specific) configuration for Sphinx
+#
+
+# type: ignore
+# pylint: disable=wildcard-import
+# pylint: disable=undefined-variable
+
+from __future__ import print_function, unicode_literals
+
 from esp_docs.conf_docs import *  # noqa: F403,F401
 
 extensions += ['sphinx_copybutton',
@@ -12,8 +23,7 @@ github_repo = 'espressif/esp-modbus'
 # context used by sphinx_idf_theme
 html_context['github_user'] = 'espressif'
 html_context['github_repo'] = 'esp-modbus'
-
+html_static_path = ['../_static']
-html_static_path = ["../_static"]
 
 # Extra options required by sphinx_idf_theme
 project_slug = 'esp-modbus'

freemodbus/modbus/ascii/mbascii.c

@@ -154,7 +154,7 @@ eMBASCIIReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLength )
     UCHAR          *pucMBASCIIFrame = ( UCHAR* ) ucASCIIBuf;
     USHORT          usFrameLength = usRcvBufferPos;
 
-    if( xMBSerialPortGetRequest( &pucMBASCIIFrame, &usFrameLength ) == FALSE )
+    if( xMBPortSerialGetRequest( &pucMBASCIIFrame, &usFrameLength ) == FALSE )
     {
         return MB_EIO;
     }
@@ -217,7 +217,7 @@ eMBASCIISend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLength )
         eSndState = STATE_TX_START;
         EXIT_CRITICAL_SECTION(  );
 
-        if ( xMBSerialPortSendResponse( ( UCHAR * ) pucSndBufferCur, usSndBufferCount ) == FALSE )
+        if ( xMBPortSerialSendResponse( ( UCHAR * ) pucSndBufferCur, usSndBufferCount ) == FALSE )
         {
             eStatus = MB_EIO;
         }

freemodbus/modbus/ascii/mbascii_m.c

@@ -157,7 +157,7 @@ eMBMasterASCIIReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLen
     UCHAR          *pucMBASCIIFrame = ( UCHAR* ) ucMasterASCIIRcvBuf;
     USHORT          usFrameLength = usMasterRcvBufferPos;
 
-    if( xMBMasterSerialPortGetResponse( &pucMBASCIIFrame, &usFrameLength ) == FALSE )
+    if( xMBMasterPortSerialGetResponse( &pucMBASCIIFrame, &usFrameLength ) == FALSE )
     {
         return MB_EIO;
     }
@@ -181,8 +181,8 @@ eMBMasterASCIIReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLen
 
        /* Return the start of the Modbus PDU to the caller. */
        *pucFrame = ( UCHAR * ) & pucMBASCIIFrame[MB_SER_PDU_PDU_OFF];
-   } else {
+    } else {
-        eStatus = MB_EIO;
+      eStatus = MB_EIO;
     }
     EXIT_CRITICAL_SECTION(  );
     return eStatus;
@@ -219,7 +219,7 @@ eMBMasterASCIISend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLengt
         eSndState = STATE_M_TX_START;
         EXIT_CRITICAL_SECTION(  );
 
-        if ( xMBMasterSerialPortSendRequest( ( UCHAR * ) pucMasterSndBufferCur, usMasterSndBufferCount ) == FALSE )
+        if ( xMBMasterPortSerialSendRequest( ( UCHAR * ) pucMasterSndBufferCur, usMasterSndBufferCount ) == FALSE )
         {
             eStatus = MB_EIO;
         }

freemodbus/modbus/include/mb_m.h

@@ -408,6 +408,7 @@ BOOL xMBMasterRequestIsBroadcast( void );
 eMBMasterErrorEventType eMBMasterGetErrorType( void );
 void vMBMasterSetErrorType( eMBMasterErrorEventType errorType );
 eMBMasterReqErrCode eMBMasterWaitRequestFinish( void );
+eMBMode ucMBMasterGetCommMode( void );
 
 /* ----------------------- Callback -----------------------------------------*/
 

freemodbus/modbus/include/mbport.h

@@ -145,9 +145,9 @@ BOOL            xMBPortSerialGetByte( CHAR * pucByte );
 
 BOOL            xMBPortSerialPutByte( CHAR ucByte );
 
-BOOL            xMBSerialPortGetRequest( UCHAR **ppucMBSerialFrame, USHORT * pusSerialLength ) __attribute__ ((weak));
+BOOL            xMBPortSerialGetRequest( UCHAR **ppucMBSerialFrame, USHORT * pusSerialLength ) __attribute__ ((weak));
 
-BOOL            xMBSerialPortSendResponse( UCHAR *pucMBSerialFrame, USHORT usSerialLength ) __attribute__ ((weak));
+BOOL            xMBPortSerialSendResponse( UCHAR *pucMBSerialFrame, USHORT usSerialLength ) __attribute__ ((weak));
 
 #if MB_MASTER_RTU_ENABLED || MB_MASTER_ASCII_ENABLED
 BOOL            xMBMasterPortSerialInit( UCHAR ucPort, ULONG ulBaudRate,
@@ -163,9 +163,11 @@ BOOL            xMBMasterPortSerialGetByte( CHAR * pucByte );
 
 BOOL            xMBMasterPortSerialPutByte( CHAR ucByte );
 
-BOOL            xMBMasterSerialPortGetResponse( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength );
+BOOL            xMBMasterPortSerialGetResponse( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength ); 
 
-BOOL            xMBMasterSerialPortSendRequest( UCHAR *pucMBSerialFrame, USHORT usSerialLength );
+BOOL            xMBMasterPortSerialSendRequest( UCHAR *pucMBSerialFrame, USHORT usSerialLength );
+
+void            vMBMasterRxFlush( void );
 
 #endif
 

freemodbus/modbus/mb_m.c

@@ -310,11 +310,13 @@ eMBMasterDisable( void )
 eMBErrorCode
 eMBMasterPoll( void )
 {
-    static UCHAR    *ucMBFrame = NULL;
+    static UCHAR    *ucMBSendFrame = NULL;
+    static UCHAR    *ucMBRcvFrame = NULL;
     static UCHAR    ucRcvAddress;
     static UCHAR    ucFunctionCode;
     static USHORT   usLength;
     static eMBException eException;
+    static BOOL     xTransactionIsActive = FALSE;
     int             i;
     int             j;
     eMBErrorCode    eStatus = MB_ENOERR;
@@ -340,49 +342,63 @@ eMBMasterPoll( void )
             } else if ( MB_PORT_CHECK_EVENT( eEvent, EV_MASTER_FRAME_TRANSMIT ) ) {
                 ESP_LOGD(MB_PORT_TAG, "%s:EV_MASTER_FRAME_TRANSMIT", __func__);
                 /* Master is busy now. */
-                vMBMasterGetPDUSndBuf( &ucMBFrame );
+                vMBMasterGetPDUSndBuf( &ucMBSendFrame );
-                ESP_LOG_BUFFER_HEX_LEVEL("POLL transmit buffer", (void*)ucMBFrame, usMBMasterGetPDUSndLength(), ESP_LOG_DEBUG);
+                ESP_LOG_BUFFER_HEX_LEVEL("POLL transmit buffer", (void*)ucMBSendFrame, usMBMasterGetPDUSndLength(), ESP_LOG_DEBUG);
-                eStatus = peMBMasterFrameSendCur( ucMBMasterGetDestAddress(), ucMBFrame, usMBMasterGetPDUSndLength() );
+                eStatus = peMBMasterFrameSendCur( ucMBMasterGetDestAddress(), ucMBSendFrame, usMBMasterGetPDUSndLength() );
                 if (eStatus != MB_ENOERR)
                 {
+                    vMBMasterSetErrorType(EV_ERROR_RECEIVE_DATA);
+                    ( void ) xMBMasterPortEventPost( EV_MASTER_ERROR_PROCESS );
                     ESP_LOGE( MB_PORT_TAG, "%s:Frame send error. %d", __func__, eStatus );
                 }
                 MB_PORT_CLEAR_EVENT( eEvent, EV_MASTER_FRAME_TRANSMIT );
             } else if ( MB_PORT_CHECK_EVENT( eEvent, EV_MASTER_FRAME_SENT ) ) {
                 ESP_LOGD( MB_PORT_TAG, "%s:EV_MASTER_FRAME_SENT", __func__ );
-                ESP_LOG_BUFFER_HEX_LEVEL("POLL sent buffer", (void*)ucMBFrame, usMBMasterGetPDUSndLength(), ESP_LOG_DEBUG);
+                ESP_LOG_BUFFER_HEX_LEVEL("POLL sent buffer", (void*)ucMBSendFrame, usMBMasterGetPDUSndLength(), ESP_LOG_DEBUG);
+                xTransactionIsActive = TRUE;
                 MB_PORT_CLEAR_EVENT( eEvent, EV_MASTER_FRAME_SENT );
             } else if ( MB_PORT_CHECK_EVENT( eEvent, EV_MASTER_FRAME_RECEIVED ) ) {
-                eStatus = peMBMasterFrameReceiveCur( &ucRcvAddress, &ucMBFrame, &usLength);
+                if (xTransactionIsActive) {
+                    eStatus = peMBMasterFrameReceiveCur( &ucRcvAddress, &ucMBRcvFrame, &usLength);
+                    MB_PORT_CHECK(ucMBRcvFrame, MB_EILLSTATE, "Receive buffer initialization fail.");
+                    MB_PORT_CHECK(ucMBSendFrame, MB_EILLSTATE, "Send buffer initialization fail.");
+                    // Check if the frame is for us. If not ,send an error process event.
+                    if ( ( eStatus == MB_ENOERR ) && ( ucRcvAddress == ucMBMasterGetDestAddress() ) )
+                    {
+                        if ( ( ucMBRcvFrame[MB_PDU_FUNC_OFF]  & ~MB_FUNC_ERROR ) == ( ucMBSendFrame[MB_PDU_FUNC_OFF] ) ) {
+                            ESP_LOGD(MB_PORT_TAG, "%s: Packet data received successfully (%u).", __func__, eStatus);
+                            ESP_LOG_BUFFER_HEX_LEVEL("POLL receive buffer", (void*)ucMBRcvFrame, (uint16_t)usLength, ESP_LOG_DEBUG);
 
-                // Check if the frame is for us. If not ,send an error process event.
+                            ( void ) xMBMasterPortEventPost( EV_MASTER_EXECUTE );
-                if ( ( eStatus == MB_ENOERR ) && ( ( ucRcvAddress == ucMBMasterGetDestAddress() )
+                        } else {
-                                              || ( ucRcvAddress == MB_TCP_PSEUDO_ADDRESS ) ) )
+                            ESP_LOGE( MB_PORT_TAG, "Drop incorrect frame, receive_func(%u) != send_func(%u)",
-                {
+                                            ucMBRcvFrame[MB_PDU_FUNC_OFF], ucMBSendFrame[MB_PDU_FUNC_OFF]);
-                    ( void ) xMBMasterPortEventPost( EV_MASTER_EXECUTE );
+                            vMBMasterSetErrorType(EV_ERROR_RECEIVE_DATA);
-                    ESP_LOGD(MB_PORT_TAG, "%s: Packet data received successfully (%u).", __func__, eStatus);
+                            ( void ) xMBMasterPortEventPost( EV_MASTER_ERROR_PROCESS );
-                    ESP_LOG_BUFFER_HEX_LEVEL("POLL receive buffer", (void*)ucMBFrame, (uint16_t)usLength, ESP_LOG_DEBUG);
+                        }
-                }
+                    }
-                else
+                    else
-                {
+                    {
-                    vMBMasterSetErrorType(EV_ERROR_RECEIVE_DATA);
+                        vMBMasterSetErrorType(EV_ERROR_RECEIVE_DATA);
-                    ( void ) xMBMasterPortEventPost( EV_MASTER_ERROR_PROCESS );
+                        ( void ) xMBMasterPortEventPost( EV_MASTER_ERROR_PROCESS );
-                    ESP_LOGD( MB_PORT_TAG, "%s: Packet data receive failed (addr=%u)(%u).",
+                        ESP_LOGD( MB_PORT_TAG, "%s: Packet data receive failed (addr=%u)(%u).",
-                                           __func__, ucRcvAddress, eStatus);
+                                               __func__, ucRcvAddress, eStatus);
+                    }
+                } else {
+                    // Ignore the `EV_MASTER_FRAME_RECEIVED` event because the respond timeout occurred
+                    // and this is likely respond to previous transaction
+                    ESP_LOGE( MB_PORT_TAG, "Drop data received outside of transaction.");
                 }
                 MB_PORT_CLEAR_EVENT( eEvent, EV_MASTER_FRAME_RECEIVED );
             } else if ( MB_PORT_CHECK_EVENT( eEvent, EV_MASTER_EXECUTE ) ) {
-                if ( !ucMBFrame )
+                MB_PORT_CHECK(ucMBRcvFrame, MB_EILLSTATE, "receive buffer initialization fail.");
-                {
-                    return MB_EILLSTATE;
-                }
                 ESP_LOGD(MB_PORT_TAG, "%s:EV_MASTER_EXECUTE", __func__);
-                ucFunctionCode = ucMBFrame[MB_PDU_FUNC_OFF];
+                ucFunctionCode = ucMBRcvFrame[MB_PDU_FUNC_OFF];
                 eException = MB_EX_ILLEGAL_FUNCTION;
                 /* If receive frame has exception. The receive function code highest bit is 1.*/
                 if (ucFunctionCode & MB_FUNC_ERROR)
                 {
-                    eException = (eMBException)ucMBFrame[MB_PDU_DATA_OFF];
+                    eException = (eMBException)ucMBRcvFrame[MB_PDU_DATA_OFF];
                 } else {
                     for ( i = 0; i < MB_FUNC_HANDLERS_MAX; i++ )
                     {
@@ -403,12 +419,12 @@ eMBMasterPoll( void )
                                 for(j = 1; j <= MB_MASTER_TOTAL_SLAVE_NUM; j++)
                                 {
                                     vMBMasterSetDestAddress(j);
-                                    eException = xMasterFuncHandlers[i].pxHandler(ucMBFrame, &usLength);
+                                    eException = xMasterFuncHandlers[i].pxHandler(ucMBRcvFrame, &usLength);
                                 }
                             }
                             else
                             {
-                                eException = xMasterFuncHandlers[i].pxHandler( ucMBFrame, &usLength );
+                                eException = xMasterFuncHandlers[i].pxHandler( ucMBRcvFrame, &usLength );
                             }
                             vMBMasterSetCBRunInMasterMode( FALSE );
                             break;
@@ -434,20 +450,20 @@ eMBMasterPoll( void )
                 ESP_LOGD( MB_PORT_TAG, "%s:EV_MASTER_ERROR_PROCESS", __func__ );
                 /* Execute specified error process callback function. */
                 errorType = eMBMasterGetErrorType( );
-                vMBMasterGetPDUSndBuf( &ucMBFrame );
+                vMBMasterGetPDUSndBuf( &ucMBSendFrame );
                 switch ( errorType )
                 {
                     case EV_ERROR_RESPOND_TIMEOUT:
                         vMBMasterErrorCBRespondTimeout( ucMBMasterGetDestAddress( ),
-                                ucMBFrame, usMBMasterGetPDUSndLength( ) );
+                                ucMBSendFrame, usMBMasterGetPDUSndLength( ) );
                         break;
                     case EV_ERROR_RECEIVE_DATA:
                         vMBMasterErrorCBReceiveData( ucMBMasterGetDestAddress( ),
-                                ucMBFrame, usMBMasterGetPDUSndLength( ) );
+                                ucMBSendFrame, usMBMasterGetPDUSndLength( ) );
                         break;
                     case EV_ERROR_EXECUTE_FUNCTION:
                         vMBMasterErrorCBExecuteFunction( ucMBMasterGetDestAddress( ),
-                                ucMBFrame, usMBMasterGetPDUSndLength( ) );
+                                ucMBSendFrame, usMBMasterGetPDUSndLength( ) );
                         break;
                     case EV_ERROR_OK:
                         vMBMasterCBRequestSuccess( );
@@ -456,6 +472,7 @@ eMBMasterPoll( void )
                         ESP_LOGE( MB_PORT_TAG, "%s: incorrect error type = %d.", __func__, errorType);
                         break;
                 }
+                vMBMasterPortTimersDisable( );
                 vMBMasterSetErrorType( EV_ERROR_INIT );
                 MB_PORT_CLEAR_EVENT( eEvent, EV_MASTER_ERROR_PROCESS );
                 vMBMasterRunResRelease( );
@@ -542,8 +559,15 @@ BOOL MB_PORT_ISR_ATTR xMBMasterRequestIsBroadcast( void )
 }
 
 /* The master request is broadcast? */
-void vMBMasterRequestSetType( BOOL xIsBroadcast ){
+void vMBMasterRequestSetType( BOOL xIsBroadcast )
+{
     xFrameIsBroadcast = xIsBroadcast;
 }
 
+// Get Modbus Master communication mode.
+eMBMode ucMBMasterGetCommMode(void)
+{
+    return eMBMasterCurrentMode;
+}
+
 #endif // MB_MASTER_RTU_ENABLED || MB_MASTER_ASCII_ENABLED || MB_MASTER_TCP_ENABLED

freemodbus/modbus/rtu/mbrtu.c

@@ -158,7 +158,7 @@ eMBRTUReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLength )
     UCHAR          *pucMBRTUFrame = ( UCHAR* ) ucRTUBuf;
     USHORT          usFrameLength = usRcvBufferPos;
 
-    if( xMBSerialPortGetRequest( &pucMBRTUFrame, &usFrameLength ) == FALSE )
+    if( xMBPortSerialGetRequest( &pucMBRTUFrame, &usFrameLength ) == FALSE )
     {
         return MB_EIO;
     }
@@ -222,7 +222,7 @@ eMBRTUSend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLength )
         eSndState = STATE_TX_XMIT;
         EXIT_CRITICAL_SECTION(  );
 
-        if( xMBSerialPortSendResponse( ( UCHAR * ) pucSndBufferCur, usSndBufferCount ) == FALSE )
+        if( xMBPortSerialSendResponse( ( UCHAR * ) pucSndBufferCur, usSndBufferCount ) == FALSE )
         {
             eStatus = MB_EIO;
         }

freemodbus/modbus/rtu/mbrtu_m.c

@@ -164,7 +164,7 @@ eMBMasterRTUReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLengt
     UCHAR          *pucMBRTUFrame = ( UCHAR* ) ucMasterRTURcvBuf;
     USHORT          usFrameLength = usMasterRcvBufferPos;
 
-    if( xMBMasterSerialPortGetResponse( &pucMBRTUFrame, &usFrameLength ) == FALSE )
+    if( xMBMasterPortSerialGetResponse( &pucMBRTUFrame, &usFrameLength ) == FALSE )
     {
         return MB_EIO;
     }
@@ -231,7 +231,7 @@ eMBMasterRTUSend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLength
         /* Activate the transmitter. */
         eSndState = STATE_M_TX_XMIT;
         
-        if ( xMBMasterSerialPortSendRequest( ( UCHAR * ) pucMasterSndBufferCur, usMasterSndBufferCount ) == FALSE )
+        if ( xMBMasterPortSerialSendRequest( ( UCHAR * ) pucMasterSndBufferCur, usMasterSndBufferCount ) == FALSE )
         {
             eStatus = MB_EIO;
         }

freemodbus/port/port.c

@@ -73,13 +73,61 @@ vMBPortSetMode( UCHAR ucMode )
     EXIT_CRITICAL_SECTION();
 }
 
+#if MB_MASTER_RTU_ENABLED || MB_MASTER_ASCII_ENABLED || MB_SLAVE_RTU_ENABLED || MB_SLAVE_ASCII_ENABLED
+
 BOOL xMBPortSerialWaitEvent(QueueHandle_t xMbUartQueue, uart_event_t* pxEvent, ULONG xTimeout)
 {
     BOOL xResult = (BaseType_t)xQueueReceive(xMbUartQueue, (void*)pxEvent, (TickType_t) xTimeout);
-    ESP_LOGD(__func__, "UART event: %d ", pxEvent->type);
+    ESP_LOGD(MB_PORT_TAG, "%s, UART event: %d ", __func__, pxEvent->type);
     return xResult;
 }
 
+#endif
+
+#if MB_MASTER_RTU_ENABLED || MB_MASTER_ASCII_ENABLED
+
+/*
+ * The function is called from ASCII/RTU module to get processed data buffer. Sets the
+ * received buffer and its length using parameters.
+ */
+__attribute__ ((weak))
+BOOL xMBMasterPortSerialGetResponse( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength ) 
+{
+    ESP_LOGD(MB_PORT_TAG, " %s default", __func__);
+    return TRUE;
+}
+
+/*
+ * The function is called from ASCII/RTU module to set processed data buffer
+ * to be sent in transmitter state machine.
+ */
+__attribute__ ((weak))
+BOOL xMBMasterPortSerialSendRequest( UCHAR *pucMBSerialFrame, USHORT usSerialLength )
+{
+    ESP_LOGD(MB_PORT_TAG, "%s default", __func__);
+    return TRUE;
+}
+
+#endif
+
+#if MB_SLAVE_RTU_ENABLED || MB_SLAVE_ASCII_ENABLED
+
+__attribute__ ((weak))
+BOOL xMBPortSerialGetRequest( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength )
+{
+    ESP_LOGD(MB_PORT_TAG, "%s default", __func__);
+    return TRUE;
+}
+
+__attribute__ ((weak))
+BOOL xMBPortSerialSendResponse( UCHAR *pucMBSerialFrame, USHORT usSerialLength )
+{
+    ESP_LOGD(MB_PORT_TAG, "%s default", __func__);
+    return TRUE;
+}
+
+#endif
+
 #if MB_TCP_DEBUG
 
 // This function is kept to realize legacy freemodbus frame logging functionality

freemodbus/port/portserial.c

@@ -260,17 +260,6 @@ BOOL xMBPortSerialInit(UCHAR ucPORT, ULONG ulBaudRate,
     return TRUE;
 }
 
-BOOL xMBSerialPortGetRequest( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength )
-{
-    BOOL eStatus = TRUE;
-    return eStatus;
-}
-
-BOOL xMBSerialPortSendResponse( UCHAR *pucMBSerialFrame, USHORT usSerialLength )
-{
-    return TRUE;
-}
-
 void vMBPortSerialClose(void)
 {
     (void)vTaskSuspend(xMbTaskHandle);

freemodbus/port/portserial_m.c

@@ -52,6 +52,9 @@
 #include "port_serial_master.h"
 
 /* ----------------------- Defines ------------------------------------------*/
+#define MB_SERIAL_RX_SEMA_TOUT_MS   (1000)
+#define MB_SERIAL_RX_SEMA_TOUT      (pdMS_TO_TICKS(MB_SERIAL_RX_SEMA_TOUT_MS))
+#define MB_SERIAL_RX_FLUSH_RETRY    (2)
 
 /* ----------------------- Static variables ---------------------------------*/
 static const CHAR *TAG = "MB_MASTER_SERIAL";
@@ -66,16 +69,67 @@ static UCHAR ucUartNumber = UART_NUM_MAX - 1;
 static BOOL bRxStateEnabled = FALSE; // Receiver enabled flag
 static BOOL bTxStateEnabled = FALSE; // Transmitter enabled flag
 
+static SemaphoreHandle_t xMasterSemaRxHandle; // Rx blocking semaphore handle
+
+static BOOL xMBMasterPortRxSemaInit( void )
+{
+    xMasterSemaRxHandle = xSemaphoreCreateBinary();
+    MB_PORT_CHECK((xMasterSemaRxHandle != NULL), FALSE , "%s: RX semaphore create failure.", __func__);
+    return TRUE;
+}
+
+static BOOL xMBMasterPortRxSemaTake( LONG lTimeOut )
+{
+    BaseType_t xStatus = pdTRUE;
+    xStatus = xSemaphoreTake(xMasterSemaRxHandle, lTimeOut );
+    MB_PORT_CHECK((xStatus == pdTRUE), FALSE , "%s: RX semaphore take failure.", __func__);
+    ESP_LOGV(MB_PORT_TAG,"%s:Take RX semaphore (%lu ticks).", __func__, lTimeOut);
+    return TRUE;
+}
+
+static void vMBMasterRxSemaRelease( void )
+{
+    BaseType_t xStatus = pdFALSE;
+    xStatus = xSemaphoreGive(xMasterSemaRxHandle);
+    if (xStatus != pdTRUE) {
+        ESP_LOGD(MB_PORT_TAG,"%s:RX semaphore is free.", __func__);
+    }
+}
+
+static BOOL vMBMasterRxSemaIsBusy( void )
+{
+    BaseType_t xStatus = pdFALSE;
+    xStatus = (uxSemaphoreGetCount(xMasterSemaRxHandle) == 0) ? TRUE : FALSE;
+    return xStatus;
+}
+
+void vMBMasterRxFlush( void )
+{
+    size_t xSize = 1;
+    esp_err_t xErr = ESP_OK;
+    for (int xCount = 0; (xCount < MB_SERIAL_RX_FLUSH_RETRY) && xSize; xCount++) {
+        xErr = uart_get_buffered_data_len(ucUartNumber, &xSize);
+        MB_PORT_CHECK((xErr == ESP_OK), ; , "mb flush serial fail, error = 0x%x.", xErr);
+        BaseType_t xStatus = xQueueReset(xMbUartQueue);
+        if (xStatus) {
+            xErr = uart_flush_input(ucUartNumber);
+            MB_PORT_CHECK((xErr == ESP_OK), ; , "mb flush serial fail, error = 0x%x.", xErr);
+        }
+    }
+}
+
 void vMBMasterPortSerialEnable(BOOL bRxEnable, BOOL bTxEnable)
 {
     // This function can be called from xMBRTUTransmitFSM() of different task
     if (bTxEnable) {
+        vMBMasterRxFlush();
         bTxStateEnabled = TRUE;
     } else {
         bTxStateEnabled = FALSE;
     }
     if (bRxEnable) {
         bRxStateEnabled = TRUE;
+        vMBMasterRxSemaRelease();
         vTaskResume(xMbTaskHandle); // Resume receiver task
     } else {
         vTaskSuspend(xMbTaskHandle); // Block receiver task
@@ -88,12 +142,12 @@ static USHORT usMBMasterPortSerialRxPoll(size_t xEventSize)
     BOOL xStatus = TRUE;
     USHORT usCnt = 0;
 
-    if (bRxStateEnabled) {
+    xStatus = xMBMasterPortRxSemaTake(MB_SERIAL_RX_SEMA_TOUT);
+    if (xStatus) {
         while(xStatus && (usCnt++ <= xEventSize)) {
             // Call the Modbus stack callback function and let it fill the stack buffers.
             xStatus = pxMBMasterFrameCBByteReceived(); // callback to receive FSM
         }
-
         // The buffer is transferred into Modbus stack and is not needed here any more
         uart_flush_input(ucUartNumber);
         ESP_LOGD(TAG, "Received data: %d(bytes in buffer)\n", (uint32_t)usCnt);
@@ -147,13 +201,17 @@ static void vUartTask(void* pvParameters)
                     // This flag set in the event means that no more
                     // data received during configured timeout and UART TOUT feature is triggered
                     if (xEvent.timeout_flag) {
+                        // Response is received but previous packet processing is pending
+                        // Do not wait completion of processing and just discard received data as incorrect
+                        if (vMBMasterRxSemaIsBusy()) {
+                            vMBMasterRxFlush();
+                            break;
+                        }
                         // Get buffered data length
                         ESP_ERROR_CHECK(uart_get_buffered_data_len(ucUartNumber, &xEvent.size));
                         // Read received data and send it to modbus stack
                         usResult = usMBMasterPortSerialRxPoll(xEvent.size);
                         ESP_LOGD(TAG,"Timeout occured, processed: %d bytes", usResult);
-                        // Block receiver task until data is not processed
-                        vTaskSuspend(NULL);
                     }
                     break;
                 //Event of HW FIFO overflow detected
@@ -253,7 +311,8 @@ BOOL xMBMasterPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits,
 
     // Set always timeout flag to trigger timeout interrupt even after rx fifo full
     uart_set_always_rx_timeout(ucUartNumber, true);
-
+    MB_PORT_CHECK((xMBMasterPortRxSemaInit()), FALSE,
+                        "mb serial RX semaphore create fail.");
     // Create a task to handle UART events
     BaseType_t xStatus = xTaskCreatePinnedToCore(vUartTask, "uart_queue_task",
                                                     MB_SERIAL_TASK_STACK_SIZE,
@@ -272,24 +331,6 @@ BOOL xMBMasterPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits,
     return TRUE;
 }
 
-/*
- * The function is called from ASCII/RTU module to get processed data buffer. Sets the
- * received buffer and its length using parameters.
- */
-BOOL xMBMasterSerialPortGetResponse( UCHAR **ppucMBSerialFrame, USHORT * usSerialLength )
-{
-    return TRUE;
-}
-
-/*
- * The function is called from ASCII/RTU module to set processed data buffer
- * to be sent in transmitter state machine.
- */
-BOOL xMBMasterSerialPortSendRequest( UCHAR *pucMBSerialFrame, USHORT usSerialLength )
-{
-    return TRUE;
-}
-
 void vMBMasterPortSerialClose(void)
 {
     (void)vTaskDelete(xMbTaskHandle);

idf_component.yml

@@ -1,4 +1,4 @@
-version: "1.0.5"
+version: "1.0.6"
 description: ESP-MODBUS is the official Modbus library for Espressif SoCs.
 url: https://github.com/espressif/esp-modbus
 dependencies: