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Diffstat (limited to 'apps/modbus/ascii/mbascii.c')
| -rw-r--r-- | apps/modbus/ascii/mbascii.c | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/apps/modbus/ascii/mbascii.c b/apps/modbus/ascii/mbascii.c new file mode 100644 index 000000000..c513457ea --- /dev/null +++ b/apps/modbus/ascii/mbascii.c @@ -0,0 +1,486 @@ +/* + * 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 |