1 /* 2 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU. 3 * Copyright (c) 2006 Christian Walter <[email protected]> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * File: $Id: mbfuncinput.c,v 1.10 2007/09/12 10:15:56 wolti Exp $ 29 */ 30 31 /* ----------------------- System includes ----------------------------------*/ 32 #include "stdlib.h" 33 #include "string.h" 34 35 /* ----------------------- Platform includes --------------------------------*/ 36 #include "port.h" 37 38 /* ----------------------- Modbus includes ----------------------------------*/ 39 #include "mb.h" 40 #include "mbframe.h" 41 #include "mbproto.h" 42 #include "mbconfig.h" 43 44 /* ----------------------- Defines ------------------------------------------*/ 45 #define MB_PDU_FUNC_READ_ADDR_OFF ( MB_PDU_DATA_OFF ) 46 #define MB_PDU_FUNC_READ_REGCNT_OFF ( MB_PDU_DATA_OFF + 2 ) 47 #define MB_PDU_FUNC_READ_SIZE ( 4 ) 48 #define MB_PDU_FUNC_READ_REGCNT_MAX ( 0x007D ) 49 50 #define MB_PDU_FUNC_READ_RSP_BYTECNT_OFF ( MB_PDU_DATA_OFF ) 51 52 /* ----------------------- Static functions ---------------------------------*/ 53 eMBException prveMBError2Exception( eMBErrorCode eErrorCode ); 54 55 /* ----------------------- Start implementation -----------------------------*/ 56 #if MB_FUNC_READ_INPUT_ENABLED > 0 57 58 eMBException 59 eMBFuncReadInputRegister( UCHAR * pucFrame, USHORT * usLen ) 60 { 61 USHORT usRegAddress; 62 USHORT usRegCount; 63 UCHAR *pucFrameCur; 64 65 eMBException eStatus = MB_EX_NONE; 66 eMBErrorCode eRegStatus; 67 68 if( *usLen == ( MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN ) ) 69 { 70 usRegAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8 ); 71 usRegAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1] ); 72 usRegAddress++; 73 74 usRegCount = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF] << 8 ); 75 usRegCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF + 1] ); 76 77 /* Check if the number of registers to read is valid. If not 78 * return Modbus illegal data value exception. 79 */ 80 if( ( usRegCount >= 1 ) 81 && ( usRegCount < MB_PDU_FUNC_READ_REGCNT_MAX ) ) 82 { 83 /* Set the current PDU data pointer to the beginning. */ 84 pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF]; 85 *usLen = MB_PDU_FUNC_OFF; 86 87 /* First byte contains the function code. */ 88 *pucFrameCur++ = MB_FUNC_READ_INPUT_REGISTER; 89 *usLen += 1; 90 91 /* Second byte in the response contain the number of bytes. */ 92 *pucFrameCur++ = ( UCHAR )( usRegCount * 2 ); 93 *usLen += 1; 94 95 eRegStatus = 96 eMBRegInputCB( pucFrameCur, usRegAddress, usRegCount ); 97 98 /* If an error occured convert it into a Modbus exception. */ 99 if( eRegStatus != MB_ENOERR ) 100 { 101 eStatus = prveMBError2Exception( eRegStatus ); 102 } 103 else 104 { 105 *usLen += usRegCount * 2; 106 } 107 } 108 else 109 { 110 eStatus = MB_EX_ILLEGAL_DATA_VALUE; 111 } 112 } 113 else 114 { 115 /* Can't be a valid read input register request because the length 116 * is incorrect. */ 117 eStatus = MB_EX_ILLEGAL_DATA_VALUE; 118 } 119 return eStatus; 120 } 121 122 #endif 123