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OVMS3-idf/components/freemodbus/modbus/ascii/mbascii.c
Alex Lisitsyn f0eb9985b9 examples: freemodbus port slave basic implementation 
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
2018-10-17 12:47:12 +02:00

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/*
* FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
* Copyright (c) 2006 Christian Walter <wolti@sil.at>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* File: $Id: mbascii.c,v 1.17 2010/06/06 13:47:07 wolti Exp $
*/
/* ----------------------- System includes ----------------------------------*/
#include "stdlib.h"
#include "string.h"
/* ----------------------- Platform includes --------------------------------*/
#include "port.h"
/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbconfig.h"
#include "mbascii.h"
#include "mbframe.h"
#include "mbcrc.h"
#include "mbport.h"
#if MB_ASCII_ENABLED > 0
/* ----------------------- Defines ------------------------------------------*/
#define MB_ASCII_DEFAULT_CR '\r' /*!< Default CR character for Modbus ASCII. */
#define MB_ASCII_DEFAULT_LF '\n' /*!< Default LF character for Modbus ASCII. */
#define MB_SER_PDU_SIZE_MIN 3 /*!< Minimum size of a Modbus ASCII frame. */
#define MB_SER_PDU_SIZE_MAX 256 /*!< Maximum size of a Modbus ASCII frame. */
#define MB_SER_PDU_SIZE_LRC 1 /*!< Size of LRC field in PDU. */
#define MB_SER_PDU_ADDR_OFF 0 /*!< Offset of slave address in Ser-PDU. */
#define MB_SER_PDU_PDU_OFF 1 /*!< Offset of Modbus-PDU in Ser-PDU. */
/* ----------------------- Type definitions ---------------------------------*/
typedef enum
{
STATE_RX_IDLE, /*!< Receiver is in idle state. */
STATE_RX_RCV, /*!< Frame is beeing received. */
STATE_RX_WAIT_EOF /*!< Wait for End of Frame. */
} eMBRcvState;
typedef enum
{
STATE_TX_IDLE, /*!< Transmitter is in idle state. */
STATE_TX_START, /*!< Starting transmission (':' sent). */
STATE_TX_DATA, /*!< Sending of data (Address, Data, LRC). */
STATE_TX_END, /*!< End of transmission. */
STATE_TX_NOTIFY /*!< Notify sender that the frame has been sent. */
} eMBSndState;
typedef enum
{
BYTE_HIGH_NIBBLE, /*!< Character for high nibble of byte. */
BYTE_LOW_NIBBLE /*!< Character for low nibble of byte. */
} eMBBytePos;
/* ----------------------- Static functions ---------------------------------*/
static UCHAR prvucMBCHAR2BIN( UCHAR ucCharacter );
static UCHAR prvucMBBIN2CHAR( UCHAR ucByte );
static UCHAR prvucMBLRC( UCHAR * pucFrame, USHORT usLen );
/* ----------------------- Static variables ---------------------------------*/
static volatile eMBSndState eSndState;
static volatile eMBRcvState eRcvState;
/* We reuse the Modbus RTU buffer because only one buffer is needed and the
* RTU buffer is bigger. */
extern volatile UCHAR ucRTUBuf[];
static volatile UCHAR *ucASCIIBuf = ucRTUBuf;
static volatile USHORT usRcvBufferPos;
static volatile eMBBytePos eBytePos;
static volatile UCHAR *pucSndBufferCur;
static volatile USHORT usSndBufferCount;
static volatile UCHAR ucLRC;
static volatile UCHAR ucMBLFCharacter;
/* ----------------------- Start implementation -----------------------------*/
eMBErrorCode
eMBASCIIInit( UCHAR ucSlaveAddress, UCHAR ucPort, ULONG ulBaudRate, eMBParity eParity )
{
eMBErrorCode eStatus = MB_ENOERR;
( void )ucSlaveAddress;
ENTER_CRITICAL_SECTION( );
ucMBLFCharacter = MB_ASCII_DEFAULT_LF;
if( xMBPortSerialInit( ucPort, ulBaudRate, 7, eParity ) != TRUE )
{
eStatus = MB_EPORTERR;
}
else if( xMBPortTimersInit( MB_ASCII_TIMEOUT_SEC * 20000UL ) != TRUE )
{
eStatus = MB_EPORTERR;
}
EXIT_CRITICAL_SECTION( );
return eStatus;
}
void
eMBASCIIStart( void )
{
ENTER_CRITICAL_SECTION( );
vMBPortSerialEnable( TRUE, FALSE );
eRcvState = STATE_RX_IDLE;
EXIT_CRITICAL_SECTION( );
/* No special startup required for ASCII. */
( void )xMBPortEventPost( EV_READY );
}
void
eMBASCIIStop( void )
{
ENTER_CRITICAL_SECTION( );
vMBPortSerialEnable( FALSE, FALSE );
vMBPortTimersDisable( );
EXIT_CRITICAL_SECTION( );
}
eMBErrorCode
eMBASCIIReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLength )
{
eMBErrorCode eStatus = MB_ENOERR;
ENTER_CRITICAL_SECTION( );
assert( usRcvBufferPos < MB_SER_PDU_SIZE_MAX );
/* Length and CRC check */
if( ( usRcvBufferPos >= MB_SER_PDU_SIZE_MIN )
&& ( prvucMBLRC( ( UCHAR * ) ucASCIIBuf, usRcvBufferPos ) == 0 ) )
{
/* Save the address field. All frames are passed to the upper layed
* and the decision if a frame is used is done there.
*/
*pucRcvAddress = ucASCIIBuf[MB_SER_PDU_ADDR_OFF];
/* Total length of Modbus-PDU is Modbus-Serial-Line-PDU minus
* size of address field and CRC checksum.
*/
*pusLength = ( USHORT )( usRcvBufferPos - MB_SER_PDU_PDU_OFF - MB_SER_PDU_SIZE_LRC );
/* Return the start of the Modbus PDU to the caller. */
*pucFrame = ( UCHAR * ) & ucASCIIBuf[MB_SER_PDU_PDU_OFF];
}
else
{
eStatus = MB_EIO;
}
EXIT_CRITICAL_SECTION( );
return eStatus;
}
eMBErrorCode
eMBASCIISend( UCHAR ucSlaveAddress, const UCHAR * pucFrame, USHORT usLength )
{
eMBErrorCode eStatus = MB_ENOERR;
UCHAR usLRC;
ENTER_CRITICAL_SECTION( );
/* Check if the receiver is still in idle state. If not we where too
* slow with processing the received frame and the master sent another
* frame on the network. We have to abort sending the frame.
*/
if( eRcvState == STATE_RX_IDLE )
{
/* First byte before the Modbus-PDU is the slave address. */
pucSndBufferCur = ( UCHAR * ) pucFrame - 1;
usSndBufferCount = 1;
/* Now copy the Modbus-PDU into the Modbus-Serial-Line-PDU. */
pucSndBufferCur[MB_SER_PDU_ADDR_OFF] = ucSlaveAddress;
usSndBufferCount += usLength;
/* Calculate LRC checksum for Modbus-Serial-Line-PDU. */
usLRC = prvucMBLRC( ( UCHAR * ) pucSndBufferCur, usSndBufferCount );
ucASCIIBuf[usSndBufferCount++] = usLRC;
/* Activate the transmitter. */
eSndState = STATE_TX_START;
vMBPortSerialEnable( FALSE, TRUE );
}
else
{
eStatus = MB_EIO;
}
EXIT_CRITICAL_SECTION( );
return eStatus;
}
BOOL
xMBASCIIReceiveFSM( void )
{
BOOL xNeedPoll = FALSE;
UCHAR ucByte;
UCHAR ucResult;
assert( eSndState == STATE_TX_IDLE );
( void )xMBPortSerialGetByte( ( CHAR * ) & ucByte );
switch ( eRcvState )
{
/* A new character is received. If the character is a ':' the input
* buffer is cleared. A CR-character signals the end of the data
* block. Other characters are part of the data block and their
* ASCII value is converted back to a binary representation.
*/
case STATE_RX_RCV:
/* Enable timer for character timeout. */
vMBPortTimersEnable( );
if( ucByte == ':' )
{
/* Empty receive buffer. */
eBytePos = BYTE_HIGH_NIBBLE;
usRcvBufferPos = 0;
}
else if( ucByte == MB_ASCII_DEFAULT_CR )
{
eRcvState = STATE_RX_WAIT_EOF;
}
else
{
ucResult = prvucMBCHAR2BIN( ucByte );
switch ( eBytePos )
{
/* High nibble of the byte comes first. We check for
* a buffer overflow here. */
case BYTE_HIGH_NIBBLE:
if( usRcvBufferPos < MB_SER_PDU_SIZE_MAX )
{
ucASCIIBuf[usRcvBufferPos] = ( UCHAR )( ucResult << 4 );
eBytePos = BYTE_LOW_NIBBLE;
break;
}
else
{
/* not handled in Modbus specification but seems
* a resonable implementation. */
eRcvState = STATE_RX_IDLE;
/* Disable previously activated timer because of error state. */
vMBPortTimersDisable( );
}
break;
case BYTE_LOW_NIBBLE:
ucASCIIBuf[usRcvBufferPos] |= ucResult;
usRcvBufferPos++;
eBytePos = BYTE_HIGH_NIBBLE;
break;
}
}
break;
case STATE_RX_WAIT_EOF:
if( ucByte == ucMBLFCharacter )
{
/* Disable character timeout timer because all characters are
* received. */
vMBPortTimersDisable( );
/* Receiver is again in idle state. */
eRcvState = STATE_RX_IDLE;
/* Notify the caller of eMBASCIIReceive that a new frame
* was received. */
xNeedPoll = xMBPortEventPost( EV_FRAME_RECEIVED );
}
else if( ucByte == ':' )
{
/* Empty receive buffer and back to receive state. */
eBytePos = BYTE_HIGH_NIBBLE;
usRcvBufferPos = 0;
eRcvState = STATE_RX_RCV;
/* Enable timer for character timeout. */
vMBPortTimersEnable( );
}
else
{
/* Frame is not okay. Delete entire frame. */
eRcvState = STATE_RX_IDLE;
}
break;
case STATE_RX_IDLE:
if( ucByte == ':' )
{
/* Enable timer for character timeout. */
vMBPortTimersEnable( );
/* Reset the input buffers to store the frame. */
usRcvBufferPos = 0;;
eBytePos = BYTE_HIGH_NIBBLE;
eRcvState = STATE_RX_RCV;
}
break;
}
return xNeedPoll;
}
BOOL
xMBASCIITransmitFSM( void )
{
BOOL xNeedPoll = FALSE;
UCHAR ucByte;
assert( eRcvState == STATE_RX_IDLE );
switch ( eSndState )
{
/* Start of transmission. The start of a frame is defined by sending
* the character ':'. */
case STATE_TX_START:
ucByte = ':';
xMBPortSerialPutByte( ( CHAR )ucByte );
eSndState = STATE_TX_DATA;
eBytePos = BYTE_HIGH_NIBBLE;
break;
/* Send the data block. Each data byte is encoded as a character hex
* stream with the high nibble sent first and the low nibble sent
* last. If all data bytes are exhausted we send a '\r' character
* to end the transmission. */
case STATE_TX_DATA:
if( usSndBufferCount > 0 )
{
switch ( eBytePos )
{
case BYTE_HIGH_NIBBLE:
ucByte = prvucMBBIN2CHAR( ( UCHAR )( *pucSndBufferCur >> 4 ) );
xMBPortSerialPutByte( ( CHAR ) ucByte );
eBytePos = BYTE_LOW_NIBBLE;
break;
case BYTE_LOW_NIBBLE:
ucByte = prvucMBBIN2CHAR( ( UCHAR )( *pucSndBufferCur & 0x0F ) );
xMBPortSerialPutByte( ( CHAR )ucByte );
pucSndBufferCur++;
eBytePos = BYTE_HIGH_NIBBLE;
usSndBufferCount--;
break;
}
}
else
{
xMBPortSerialPutByte( MB_ASCII_DEFAULT_CR );
eSndState = STATE_TX_END;
}
break;
/* Finish the frame by sending a LF character. */
case STATE_TX_END:
xMBPortSerialPutByte( ( CHAR )ucMBLFCharacter );
/* We need another state to make sure that the CR character has
* been sent. */
eSndState = STATE_TX_NOTIFY;
break;
/* Notify the task which called eMBASCIISend that the frame has
* been sent. */
case STATE_TX_NOTIFY:
eSndState = STATE_TX_IDLE;
xNeedPoll = xMBPortEventPost( EV_FRAME_SENT );
/* Disable transmitter. This prevents another transmit buffer
* empty interrupt. */
vMBPortSerialEnable( TRUE, FALSE );
eSndState = STATE_TX_IDLE;
break;
/* We should not get a transmitter event if the transmitter is in
* idle state. */
case STATE_TX_IDLE:
/* enable receiver/disable transmitter. */
vMBPortSerialEnable( TRUE, FALSE );
break;
}
return xNeedPoll;
}
BOOL
xMBASCIITimerT1SExpired( void )
{
switch ( eRcvState )
{
/* If we have a timeout we go back to the idle state and wait for
* the next frame.
*/
case STATE_RX_RCV:
case STATE_RX_WAIT_EOF:
eRcvState = STATE_RX_IDLE;
break;
default:
assert( ( eRcvState == STATE_RX_RCV ) || ( eRcvState == STATE_RX_WAIT_EOF ) );
break;
}
vMBPortTimersDisable( );
/* no context switch required. */
return FALSE;
}
static UCHAR
prvucMBCHAR2BIN( UCHAR ucCharacter )
{
if( ( ucCharacter >= '0' ) && ( ucCharacter <= '9' ) )
{
return ( UCHAR )( ucCharacter - '0' );
}
else if( ( ucCharacter >= 'A' ) && ( ucCharacter <= 'F' ) )
{
return ( UCHAR )( ucCharacter - 'A' + 0x0A );
}
else
{
return 0xFF;
}
}
static UCHAR
prvucMBBIN2CHAR( UCHAR ucByte )
{
if( ucByte <= 0x09 )
{
return ( UCHAR )( '0' + ucByte );
}
else if( ( ucByte >= 0x0A ) && ( ucByte <= 0x0F ) )
{
return ( UCHAR )( ucByte - 0x0A + 'A' );
}
else
{
/* Programming error. */
assert( 0 );
}
return '0';
}
static UCHAR
prvucMBLRC( UCHAR * pucFrame, USHORT usLen )
{
UCHAR ucLRC = 0; /* LRC char initialized */
while( usLen-- )
{
ucLRC += *pucFrame++; /* Add buffer byte without carry */
}
/* Return twos complement */
ucLRC = ( UCHAR ) ( -( ( CHAR ) ucLRC ) );
return ucLRC;
}
#endif
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