488 lines
15 KiB
C
488 lines
15 KiB
C
/*
|
|
* 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 <nuttx/config.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <assert.h>
|
|
|
|
/* ----------------------- Platform includes --------------------------------*/
|
|
#include "port.h"
|
|
|
|
/* ----------------------- Modbus includes ----------------------------------*/
|
|
#include <apps/modbus/mb.h>
|
|
#include <apps/modbus/mbframe.h>
|
|
#include <apps/modbus/mbport.h>
|
|
|
|
#include "mbascii.h"
|
|
#include "mbcrc.h"
|
|
|
|
#ifdef CONFIG_MB_ASCII_ENABLED
|
|
|
|
/* ----------------------- 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 uint8_t prvucMBint8_t2BIN( uint8_t ucCharacter );
|
|
|
|
static uint8_t prvucMBBIN2int8_t( uint8_t ucByte );
|
|
|
|
static uint8_t prvucMBLRC( uint8_t * pucFrame, uint16_t 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 uint8_t ucRTUBuf[];
|
|
static volatile uint8_t *ucASCIIBuf = ucRTUBuf;
|
|
|
|
static volatile uint16_t usRcvBufferPos;
|
|
static volatile eMBBytePos eBytePos;
|
|
|
|
static volatile uint8_t *pucSndBufferCur;
|
|
static volatile uint16_t usSndBufferCount;
|
|
|
|
static volatile uint8_t ucLRC;
|
|
static volatile uint8_t ucMBLFCharacter;
|
|
|
|
/* ----------------------- Start implementation -----------------------------*/
|
|
eMBErrorCode
|
|
eMBASCIIInit( uint8_t ucSlaveAddress, uint8_t ucPort, speed_t 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( CONFIG_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( uint8_t * pucRcvAddress, uint8_t ** pucFrame, uint16_t * 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( ( uint8_t * ) 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 = ( uint16_t )( usRcvBufferPos - MB_SER_PDU_PDU_OFF - MB_SER_PDU_SIZE_LRC );
|
|
|
|
/* Return the start of the Modbus PDU to the caller. */
|
|
*pucFrame = ( uint8_t * ) & ucASCIIBuf[MB_SER_PDU_PDU_OFF];
|
|
}
|
|
else
|
|
{
|
|
eStatus = MB_EIO;
|
|
}
|
|
EXIT_CRITICAL_SECTION( );
|
|
return eStatus;
|
|
}
|
|
|
|
eMBErrorCode
|
|
eMBASCIISend( uint8_t ucSlaveAddress, const uint8_t * pucFrame, uint16_t usLength )
|
|
{
|
|
eMBErrorCode eStatus = MB_ENOERR;
|
|
uint8_t 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 = ( uint8_t * ) 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( ( uint8_t * ) 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;
|
|
uint8_t ucByte;
|
|
uint8_t ucResult;
|
|
|
|
ASSERT( eSndState == STATE_TX_IDLE );
|
|
|
|
( void )xMBPortSerialGetByte( ( int8_t * ) & 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 = prvucMBint8_t2BIN( 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] = ( uint8_t )( 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;
|
|
uint8_t 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( ( int8_t )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 = prvucMBBIN2int8_t( ( uint8_t )( *pucSndBufferCur >> 4 ) );
|
|
xMBPortSerialPutByte( ( int8_t ) ucByte );
|
|
eBytePos = BYTE_LOW_NIBBLE;
|
|
break;
|
|
|
|
case BYTE_LOW_NIBBLE:
|
|
ucByte = prvucMBBIN2int8_t( ( uint8_t )( *pucSndBufferCur & 0x0F ) );
|
|
xMBPortSerialPutByte( ( int8_t )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( ( int8_t )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 uint8_t
|
|
prvucMBint8_t2BIN( uint8_t ucCharacter )
|
|
{
|
|
if( ( ucCharacter >= '0' ) && ( ucCharacter <= '9' ) )
|
|
{
|
|
return ( uint8_t )( ucCharacter - '0' );
|
|
}
|
|
else if( ( ucCharacter >= 'A' ) && ( ucCharacter <= 'F' ) )
|
|
{
|
|
return ( uint8_t )( ucCharacter - 'A' + 0x0A );
|
|
}
|
|
else
|
|
{
|
|
return 0xFF;
|
|
}
|
|
}
|
|
|
|
static uint8_t
|
|
prvucMBBIN2int8_t( uint8_t ucByte )
|
|
{
|
|
if( ucByte <= 0x09 )
|
|
{
|
|
return ( uint8_t )( '0' + ucByte );
|
|
}
|
|
else if( ( ucByte >= 0x0A ) && ( ucByte <= 0x0F ) )
|
|
{
|
|
return ( uint8_t )( ucByte - 0x0A + 'A' );
|
|
}
|
|
else
|
|
{
|
|
/* Programming error. */
|
|
ASSERT( 0 );
|
|
}
|
|
return '0';
|
|
}
|
|
|
|
|
|
static uint8_t
|
|
prvucMBLRC( uint8_t * pucFrame, uint16_t usLen )
|
|
{
|
|
uint8_t ucLocalLRC = 0; /* LRC char initialized */
|
|
|
|
while( usLen-- )
|
|
{
|
|
ucLocalLRC += *pucFrame++; /* Add buffer byte without carry */
|
|
}
|
|
|
|
/* Return twos complement */
|
|
ucLocalLRC = ( uint8_t ) ( -( ( int8_t ) ucLocalLRC ) );
|
|
return ucLocalLRC;
|
|
}
|
|
|
|
#endif
|