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This example adds functionality to support basic communication in RS485 networks using Modbus protocol. This example uses FreeModbus stack and regular UART driver API to communicate in RS485 half duplex mode. Added initial support of modbus controller pure C api to access device parameters over Modbus transport. Move freemodbus stack and port files into components folder Move the modbus_controller interface into components idf folder Source files updated after review. Add modbus interface documentation docs/en/api-reference/protocols/modbus.rst porttimer.c: fix bug with timer1 selected in the Kconfig Add support of cmake system (added cmake files) Closes https://github.com/espressif/esp-idf/issues/858
361 lines
11 KiB
C
361 lines
11 KiB
C
/*
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* FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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* Copyright (c) 2006 Christian Walter <wolti@sil.at>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* File: $Id: mbrtu.c,v 1.18 2007/09/12 10:15:56 wolti Exp $
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*/
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/* ----------------------- System includes ----------------------------------*/
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#include "stdlib.h"
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#include "string.h"
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/* ----------------------- Platform includes --------------------------------*/
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#include "port.h"
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/* ----------------------- Modbus includes ----------------------------------*/
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#include "mb.h"
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#include "mbrtu.h"
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#include "mbframe.h"
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#include "mbcrc.h"
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#include "mbport.h"
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/* ----------------------- Defines ------------------------------------------*/
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#define MB_SER_PDU_SIZE_MIN 4 /*!< Minimum size of a Modbus RTU frame. */
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#define MB_SER_PDU_SIZE_MAX 256 /*!< Maximum size of a Modbus RTU frame. */
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#define MB_SER_PDU_SIZE_CRC 2 /*!< Size of CRC field in PDU. */
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#define MB_SER_PDU_ADDR_OFF 0 /*!< Offset of slave address in Ser-PDU. */
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#define MB_SER_PDU_PDU_OFF 1 /*!< Offset of Modbus-PDU in Ser-PDU. */
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/* ----------------------- Type definitions ---------------------------------*/
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typedef enum
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{
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STATE_RX_INIT, /*!< Receiver is in initial state. */
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STATE_RX_IDLE, /*!< Receiver is in idle state. */
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STATE_RX_RCV, /*!< Frame is beeing received. */
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STATE_RX_ERROR /*!< If the frame is invalid. */
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} eMBRcvState;
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typedef enum
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{
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STATE_TX_IDLE, /*!< Transmitter is in idle state. */
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STATE_TX_XMIT /*!< Transmitter is in transfer state. */
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} eMBSndState;
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/* ----------------------- Static variables ---------------------------------*/
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static volatile eMBSndState eSndState;
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static volatile eMBRcvState eRcvState;
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volatile UCHAR ucRTUBuf[MB_SER_PDU_SIZE_MAX];
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static volatile UCHAR *pucSndBufferCur;
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static volatile USHORT usSndBufferCount;
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static volatile USHORT usRcvBufferPos;
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/* ----------------------- Start implementation -----------------------------*/
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eMBErrorCode
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eMBRTUInit( UCHAR ucSlaveAddress, UCHAR ucPort, ULONG ulBaudRate, eMBParity eParity )
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{
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eMBErrorCode eStatus = MB_ENOERR;
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ULONG usTimerT35_50us;
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( void )ucSlaveAddress;
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ENTER_CRITICAL_SECTION( );
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/* Modbus RTU uses 8 Databits. */
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if( xMBPortSerialInit( ucPort, ulBaudRate, 8, eParity ) != TRUE )
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{
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eStatus = MB_EPORTERR;
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}
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else
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{
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/* If baudrate > 19200 then we should use the fixed timer values
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* t35 = 1750us. Otherwise t35 must be 3.5 times the character time.
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*/
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if( ulBaudRate > 19200 )
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{
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usTimerT35_50us = 35; /* 1800us. */
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}
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else
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{
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/* The timer reload value for a character is given by:
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*
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* ChTimeValue = Ticks_per_1s / ( Baudrate / 11 )
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* = 11 * Ticks_per_1s / Baudrate
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* = 220000 / Baudrate
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* The reload for t3.5 is 1.5 times this value and similary
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* for t3.5.
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*/
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usTimerT35_50us = ( 7UL * 220000UL ) / ( 2UL * ulBaudRate );
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}
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if( xMBPortTimersInit( ( USHORT ) usTimerT35_50us ) != TRUE )
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{
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eStatus = MB_EPORTERR;
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}
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}
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EXIT_CRITICAL_SECTION( );
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return eStatus;
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}
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void
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eMBRTUStart( void )
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{
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ENTER_CRITICAL_SECTION( );
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/* Initially the receiver is in the state STATE_RX_INIT. we start
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* the timer and if no character is received within t3.5 we change
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* to STATE_RX_IDLE. This makes sure that we delay startup of the
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* modbus protocol stack until the bus is free.
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*/
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eRcvState = STATE_RX_INIT;
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vMBPortSerialEnable( TRUE, FALSE );
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vMBPortTimersEnable( );
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EXIT_CRITICAL_SECTION( );
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}
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void
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eMBRTUStop( void )
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{
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ENTER_CRITICAL_SECTION( );
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vMBPortSerialEnable( FALSE, FALSE );
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vMBPortTimersDisable( );
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EXIT_CRITICAL_SECTION( );
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}
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// The lines below are required to suppress GCC warnings about unused but set variable 'xFrameReceived'
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// This warning is treated as error during compilation.
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#pragma GCC diagnostic push // required for GCC
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#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
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eMBErrorCode
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eMBRTUReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLength )
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{
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BOOL xFrameReceived = FALSE;
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eMBErrorCode eStatus = MB_ENOERR;
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ENTER_CRITICAL_SECTION( );
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assert( usRcvBufferPos < MB_SER_PDU_SIZE_MAX );
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/* Length and CRC check */
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if( ( usRcvBufferPos >= MB_SER_PDU_SIZE_MIN )
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&& ( usMBCRC16( ( UCHAR * ) ucRTUBuf, usRcvBufferPos ) == 0 ) )
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{
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/* Save the address field. All frames are passed to the upper layed
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* and the decision if a frame is used is done there.
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*/
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*pucRcvAddress = ucRTUBuf[MB_SER_PDU_ADDR_OFF];
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/* Total length of Modbus-PDU is Modbus-Serial-Line-PDU minus
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* size of address field and CRC checksum.
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*/
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*pusLength = ( USHORT )( usRcvBufferPos - MB_SER_PDU_PDU_OFF - MB_SER_PDU_SIZE_CRC );
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/* Return the start of the Modbus PDU to the caller. */
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*pucFrame = ( UCHAR * ) & ucRTUBuf[MB_SER_PDU_PDU_OFF];
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xFrameReceived = TRUE;
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}
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else
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{
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eStatus = MB_EIO;
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}
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EXIT_CRITICAL_SECTION( );
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return eStatus;
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}
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#pragma GCC diagnostic pop // require GCC
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eMBErrorCode
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eMBRTUSend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLength )
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{
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eMBErrorCode eStatus = MB_ENOERR;
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USHORT usCRC16;
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ENTER_CRITICAL_SECTION( );
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/* Check if the receiver is still in idle state. If not we where to
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* slow with processing the received frame and the master sent another
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* frame on the network. We have to abort sending the frame.
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*/
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if( eRcvState == STATE_RX_IDLE )
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{
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/* First byte before the Modbus-PDU is the slave address. */
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pucSndBufferCur = ( UCHAR * ) pucFrame - 1;
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usSndBufferCount = 1;
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/* Now copy the Modbus-PDU into the Modbus-Serial-Line-PDU. */
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pucSndBufferCur[MB_SER_PDU_ADDR_OFF] = ucSlaveAddress;
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usSndBufferCount += usLength;
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/* Calculate CRC16 checksum for Modbus-Serial-Line-PDU. */
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usCRC16 = usMBCRC16( ( UCHAR * ) pucSndBufferCur, usSndBufferCount );
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ucRTUBuf[usSndBufferCount++] = ( UCHAR )( usCRC16 & 0xFF );
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ucRTUBuf[usSndBufferCount++] = ( UCHAR )( usCRC16 >> 8 );
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/* Activate the transmitter. */
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eSndState = STATE_TX_XMIT;
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vMBPortSerialEnable( FALSE, TRUE );
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}
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else
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{
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eStatus = MB_EIO;
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}
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EXIT_CRITICAL_SECTION( );
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return eStatus;
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}
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BOOL
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xMBRTUReceiveFSM( void )
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{
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BOOL xTaskNeedSwitch = FALSE;
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UCHAR ucByte;
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assert( eSndState == STATE_TX_IDLE );
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/* Always read the character. */
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( void )xMBPortSerialGetByte( ( CHAR * ) & ucByte );
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switch ( eRcvState )
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{
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/* If we have received a character in the init state we have to
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* wait until the frame is finished.
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*/
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case STATE_RX_INIT:
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vMBPortTimersEnable( );
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break;
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/* In the error state we wait until all characters in the
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* damaged frame are transmitted.
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*/
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case STATE_RX_ERROR:
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vMBPortTimersEnable( );
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break;
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/* In the idle state we wait for a new character. If a character
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* is received the t1.5 and t3.5 timers are started and the
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* receiver is in the state STATE_RX_RECEIVCE.
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*/
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case STATE_RX_IDLE:
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usRcvBufferPos = 0;
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ucRTUBuf[usRcvBufferPos++] = ucByte;
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eRcvState = STATE_RX_RCV;
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/* Enable t3.5 timers. */
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vMBPortTimersEnable( );
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break;
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/* We are currently receiving a frame. Reset the timer after
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* every character received. If more than the maximum possible
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* number of bytes in a modbus frame is received the frame is
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* ignored.
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*/
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case STATE_RX_RCV:
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if( usRcvBufferPos < MB_SER_PDU_SIZE_MAX )
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{
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ucRTUBuf[usRcvBufferPos++] = ucByte;
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}
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else
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{
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eRcvState = STATE_RX_ERROR;
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}
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vMBPortTimersEnable( );
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break;
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}
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return xTaskNeedSwitch;
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}
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BOOL
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xMBRTUTransmitFSM( void )
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{
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BOOL xNeedPoll = FALSE;
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assert( eRcvState == STATE_RX_IDLE );
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switch ( eSndState )
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{
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/* We should not get a transmitter event if the transmitter is in
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* idle state. */
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case STATE_TX_IDLE:
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/* enable receiver/disable transmitter. */
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vMBPortSerialEnable( TRUE, FALSE );
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break;
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case STATE_TX_XMIT:
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/* check if we are finished. */
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if( usSndBufferCount != 0 )
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{
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xMBPortSerialPutByte( ( CHAR )*pucSndBufferCur );
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pucSndBufferCur++; /* next byte in sendbuffer. */
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usSndBufferCount--;
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}
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else
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{
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xNeedPoll = xMBPortEventPost( EV_FRAME_SENT );
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/* Disable transmitter. This prevents another transmit buffer
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* empty interrupt. */
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vMBPortSerialEnable( TRUE, FALSE );
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eSndState = STATE_TX_IDLE;
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}
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break;
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}
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return xNeedPoll;
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}
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BOOL
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xMBRTUTimerT35Expired( void )
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{
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BOOL xNeedPoll = FALSE;
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switch ( eRcvState )
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{
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/* Timer t35 expired. Startup phase is finished. */
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case STATE_RX_INIT:
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xNeedPoll = xMBPortEventPost( EV_READY );
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break;
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/* A frame was received and t35 expired. Notify the listener that
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* a new frame was received. */
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case STATE_RX_RCV:
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xNeedPoll = xMBPortEventPost( EV_FRAME_RECEIVED );
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break;
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/* An error occured while receiving the frame. */
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case STATE_RX_ERROR:
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break;
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/* Function called in an illegal state. */
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default:
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assert( ( eRcvState == STATE_RX_INIT ) ||
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( eRcvState == STATE_RX_RCV ) || ( eRcvState == STATE_RX_ERROR ) );
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}
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vMBPortTimersDisable( );
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eRcvState = STATE_RX_IDLE;
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return xNeedPoll;
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}
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