text: /*
   * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
   * Copyright (C) 2013 Armink <armink.ztl@gmail.com>
   * 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: mbfuncdisc_m.c,v 1.60 2013/10/15 8:48:20 Armink Add Master Functions  Exp $
   */
  
  
  
  /* ----------------------- System includes ----------------------------------*/
  #include "stdlib.h"
  #include "string.h"
  
  /* ----------------------- Platform includes --------------------------------*/
  #include "port.h"
  
  /* ----------------------- Modbus includes ----------------------------------*/
  #include "mb_m.h"
  #include "mbframe.h"
  #include "mbproto.h"
  #include "mbconfig.h"
  
  /* ----------------------- Defines ------------------------------------------*/
  #define MB_PDU_REQ_READ_ADDR_OFF            ( MB_PDU_DATA_OFF + 0 )
  #define MB_PDU_REQ_READ_DISCCNT_OFF         ( MB_PDU_DATA_OFF + 2 )
  #define MB_PDU_REQ_READ_SIZE                ( 4 )
  #define MB_PDU_FUNC_READ_DISCCNT_OFF        ( MB_PDU_DATA_OFF + 0 )
  #define MB_PDU_FUNC_READ_VALUES_OFF         ( MB_PDU_DATA_OFF + 1 )
  #define MB_PDU_FUNC_READ_SIZE_MIN           ( 1 )
  
  /* ----------------------- Static functions ---------------------------------*/
  eMBException    prveMBError2Exception( eMBErrorCode eErrorCode );
  
  /* ----------------------- Start implementation -----------------------------*/
  #if MB_MASTER_RTU_ENABLED || MB_MASTER_ASCII_ENABLED || MB_MASTER_TCP_ENABLED
  
  #if MB_FUNC_READ_DISCRETE_INPUTS_ENABLED
  
  /**
   * This function will request read discrete inputs.
   *
   * @param ucSndAddr salve address
   * @param usDiscreteAddr discrete start address
   * @param usNDiscreteIn discrete total number
   * @param lTimeOut timeout (-1 will waiting forever)
   *
   * @return error code
   */
  eMBMasterReqErrCode
  eMBMasterReqReadDiscreteInputs( UCHAR ucSndAddr, USHORT usDiscreteAddr, USHORT usNDiscreteIn, LONG lTimeOut )
  {
      UCHAR                 *ucMBFrame;
      eMBMasterReqErrCode    eErrStatus = MB_MRE_NO_ERR;
  
      if ( ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM ) eErrStatus = MB_MRE_ILL_ARG;
      else if ( xMBMasterRunResTake( lTimeOut ) == FALSE ) eErrStatus = MB_MRE_MASTER_BUSY;
      else
      {
          vMBMasterGetPDUSndBuf(&ucMBFrame);
          vMBMasterSetDestAddress(ucSndAddr);
          ucMBFrame[MB_PDU_FUNC_OFF]                 = MB_FUNC_READ_DISCRETE_INPUTS;
          ucMBFrame[MB_PDU_REQ_READ_ADDR_OFF]        = usDiscreteAddr >> 8;
          ucMBFrame[MB_PDU_REQ_READ_ADDR_OFF + 1]    = usDiscreteAddr;
          ucMBFrame[MB_PDU_REQ_READ_DISCCNT_OFF ]    = usNDiscreteIn >> 8;
          ucMBFrame[MB_PDU_REQ_READ_DISCCNT_OFF + 1] = usNDiscreteIn;
          vMBMasterSetPDUSndLength( MB_PDU_SIZE_MIN + MB_PDU_REQ_READ_SIZE );
          ( void ) xMBMasterPortEventPost( EV_MASTER_FRAME_TRANSMIT );
          eErrStatus = eMBMasterWaitRequestFinish( );
      }
      return eErrStatus;
  }
  
  eMBException
  eMBMasterFuncReadDiscreteInputs( UCHAR * pucFrame, USHORT * usLen )
  {
      USHORT          usRegAddress;
      USHORT          usDiscreteCnt;
      UCHAR           ucNBytes;
      UCHAR          *ucMBFrame;
  
      eMBException    eStatus = MB_EX_NONE;
      eMBErrorCode    eRegStatus;
  
      /* If this request is broadcast, and it's read mode. This request don't need execute. */
      if ( xMBMasterRequestIsBroadcast() )
      {
          eStatus = MB_EX_NONE;
      }
      else if( *usLen >= MB_PDU_SIZE_MIN + MB_PDU_FUNC_READ_SIZE_MIN )
      {
          vMBMasterGetPDUSndBuf(&ucMBFrame);
          usRegAddress = ( USHORT )( ucMBFrame[MB_PDU_REQ_READ_ADDR_OFF] << 8 );
          usRegAddress |= ( USHORT )( ucMBFrame[MB_PDU_REQ_READ_ADDR_OFF + 1] );
          usRegAddress++;
  
          usDiscreteCnt = ( USHORT )( ucMBFrame[MB_PDU_REQ_READ_DISCCNT_OFF] << 8 );
          usDiscreteCnt |= ( USHORT )( ucMBFrame[MB_PDU_REQ_READ_DISCCNT_OFF + 1] );
  
          /* Test if the quantity of coils is a multiple of 8. If not last
           * byte is only partially field with unused coils set to zero. */
          if( ( usDiscreteCnt & 0x0007 ) != 0 )
          {
              ucNBytes = ( UCHAR )( usDiscreteCnt / 8 + 1 );
          }
          else
          {
              ucNBytes = ( UCHAR )( usDiscreteCnt / 8 );
          }
  
          /* Check if the number of registers to read is valid. If not
           * return Modbus illegal data value exception. 
           */
          if ((usDiscreteCnt >= 1) && ucNBytes == pucFrame[MB_PDU_FUNC_READ_DISCCNT_OFF])
          {
              /* Make callback to fill the buffer. */
              eRegStatus = eMBMasterRegDiscreteCB( &pucFrame[MB_PDU_FUNC_READ_VALUES_OFF], usRegAddress, usDiscreteCnt );
  
              /* If an error occured convert it into a Modbus exception. */
              if( eRegStatus != MB_ENOERR )
              {
                  eStatus = prveMBError2Exception( eRegStatus );
              }
          }
          else
          {
              eStatus = MB_EX_ILLEGAL_DATA_VALUE;
          }
      }
      else
      {
          /* Can't be a valid read coil register request because the length
           * is incorrect. */
          eStatus = MB_EX_ILLEGAL_DATA_VALUE;
      }
      return eStatus;
  }
  
  #endif
  #endif // #if MB_SERIAL_MASTER_RTU_ENABLED || MB_SERIAL_MASTER_ASCII_ENABLED || MB_MASTER_TCP_ENABLED
  