Diff: mb.h

Revision:

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+++ b/mb.h	Sun Aug 22 16:34:20 2010 +0000
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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: mb.h,v 1.17 2006/12/07 22:10:34 wolti Exp $
+ */
+
+#ifndef _MB_H
+#define _MB_H
+
+#include "port.h"
+
+#ifdef __cplusplus
+PR_BEGIN_EXTERN_C
+#endif
+
+#include "mbport.h"
+#include "mbproto.h"
+
+/*! \defgroup modbus Modbus
+ * \code #include "mb.h" \endcode
+ *
+ * This module defines the interface for the application. It contains
+ * the basic functions and types required to use the Modbus protocol stack.
+ * A typical application will want to call eMBInit() first. If the device
+ * is ready to answer network requests it must then call eMBEnable() to activate
+ * the protocol stack. In the main loop the function eMBPoll() must be called
+ * periodically. The time interval between pooling depends on the configured
+ * Modbus timeout. If an RTOS is available a separate task should be created
+ * and the task should always call the function eMBPoll().
+ *
+ * \code
+ * // Initialize protocol stack in RTU mode for a slave with address 10 = 0x0A
+ * eMBInit( MB_RTU, 0x0A, 38400, MB_PAR_EVEN );
+ * // Enable the Modbus Protocol Stack.
+ * eMBEnable(  );
+ * for( ;; )
+ * {
+ *     // Call the main polling loop of the Modbus protocol stack.
+ *     eMBPoll(  );
+ *     ...
+ * }
+ * \endcode
+ */
+
+/* ----------------------- Defines ------------------------------------------*/
+
+/*! \ingroup modbus
+ * \brief Use the default Modbus TCP port (502)
+ */
+#define MB_TCP_PORT_USE_DEFAULT 0   
+
+/* ----------------------- Type definitions ---------------------------------*/
+
+/*! \ingroup modbus
+ * \brief Modbus serial transmission modes (RTU/ASCII).
+ *
+ * Modbus serial supports two transmission modes. Either ASCII or RTU. RTU
+ * is faster but has more hardware requirements and requires a network with
+ * a low jitter. ASCII is slower and more reliable on slower links (E.g. modems)
+ */
+    typedef enum
+{
+    MB_RTU,                     /*!< RTU transmission mode. */
+    MB_ASCII,                   /*!< ASCII transmission mode. */
+    MB_TCP                      /*!< TCP mode. */
+} eMBMode;
+
+/*! \ingroup modbus
+ * \brief If register should be written or read.
+ *
+ * This value is passed to the callback functions which support either
+ * reading or writing register values. Writing means that the application
+ * registers should be updated and reading means that the modbus protocol
+ * stack needs to know the current register values.
+ *
+ * \see eMBRegHoldingCB( ), eMBRegCoilsCB( ), eMBRegDiscreteCB( ) and 
+ *   eMBRegInputCB( ).
+ */
+typedef enum
+{
+    MB_REG_READ,                /*!< Read register values and pass to protocol stack. */
+    MB_REG_WRITE                /*!< Update register values. */
+} eMBRegisterMode;
+
+/*! \ingroup modbus
+ * \brief Errorcodes used by all function in the protocol stack.
+ */
+typedef enum
+{
+    MB_ENOERR,                  /*!< no error. */
+    MB_ENOREG,                  /*!< illegal register address. */
+    MB_EINVAL,                  /*!< illegal argument. */
+    MB_EPORTERR,                /*!< porting layer error. */
+    MB_ENORES,                  /*!< insufficient resources. */
+    MB_EIO,                     /*!< I/O error. */
+    MB_EILLSTATE,               /*!< protocol stack in illegal state. */
+    MB_ETIMEDOUT                /*!< timeout error occurred. */
+} eMBErrorCode;
+
+
+/* ----------------------- Function prototypes ------------------------------*/
+/*! \ingroup modbus
+ * \brief Initialize the Modbus protocol stack.
+ *
+ * This functions initializes the ASCII or RTU module and calls the
+ * init functions of the porting layer to prepare the hardware. Please
+ * note that the receiver is still disabled and no Modbus frames are
+ * processed until eMBEnable( ) has been called.
+ *
+ * \param eMode If ASCII or RTU mode should be used.
+ * \param ucSlaveAddress The slave address. Only frames sent to this
+ *   address or to the broadcast address are processed.
+ * \param ucPort The port to use. E.g. 1 for COM1 on windows. This value
+ *   is platform dependent and some ports simply choose to ignore it.
+ * \param ulBaudRate The baudrate. E.g. 19200. Supported baudrates depend
+ *   on the porting layer.
+ * \param eParity Parity used for serial transmission.
+ *
+ * \return If no error occurs the function returns eMBErrorCode::MB_ENOERR.
+ *   The protocol is then in the disabled state and ready for activation
+ *   by calling eMBEnable( ). Otherwise one of the following error codes 
+ *   is returned:
+ *    - eMBErrorCode::MB_EINVAL If the slave address was not valid. Valid
+ *        slave addresses are in the range 1 - 247.
+ *    - eMBErrorCode::MB_EPORTERR IF the porting layer returned an error.
+ */
+eMBErrorCode    eMBInit( eMBMode eMode, UCHAR ucSlaveAddress,
+                         UCHAR ucPort, ULONG ulBaudRate, eMBParity eParity );
+
+/*! \ingroup modbus
+ * \brief Initialize the Modbus protocol stack for Modbus TCP.
+ *
+ * This function initializes the Modbus TCP Module. Please note that
+ * frame processing is still disabled until eMBEnable( ) is called.
+ *
+ * \param usTCPPort The TCP port to listen on.
+ * \return If the protocol stack has been initialized correctly the function
+ *   returns eMBErrorCode::MB_ENOERR. Otherwise one of the following error
+ *   codes is returned:
+ *    - eMBErrorCode::MB_EINVAL If the slave address was not valid. Valid
+ *        slave addresses are in the range 1 - 247.
+ *    - eMBErrorCode::MB_EPORTERR IF the porting layer returned an error.
+ */
+eMBErrorCode    eMBTCPInit( USHORT usTCPPort );
+
+/*! \ingroup modbus
+ * \brief Release resources used by the protocol stack.
+ *
+ * This function disables the Modbus protocol stack and release all
+ * hardware resources. It must only be called when the protocol stack 
+ * is disabled. 
+ *
+ * \note Note all ports implement this function. A port which wants to 
+ *   get an callback must define the macro MB_PORT_HAS_CLOSE to 1.
+ *
+ * \return If the resources where released it return eMBErrorCode::MB_ENOERR.
+ *   If the protocol stack is not in the disabled state it returns
+ *   eMBErrorCode::MB_EILLSTATE.
+ */
+eMBErrorCode    eMBClose( void );
+
+/*! \ingroup modbus
+ * \brief Enable the Modbus protocol stack.
+ *
+ * This function enables processing of Modbus frames. Enabling the protocol
+ * stack is only possible if it is in the disabled state.
+ *
+ * \return If the protocol stack is now in the state enabled it returns 
+ *   eMBErrorCode::MB_ENOERR. If it was not in the disabled state it 
+ *   return eMBErrorCode::MB_EILLSTATE.
+ */
+eMBErrorCode    eMBEnable( void );
+
+/*! \ingroup modbus
+ * \brief Disable the Modbus protocol stack.
+ *
+ * This function disables processing of Modbus frames.
+ *
+ * \return If the protocol stack has been disabled it returns 
+ *  eMBErrorCode::MB_ENOERR. If it was not in the enabled state it returns
+ *  eMBErrorCode::MB_EILLSTATE.
+ */
+eMBErrorCode    eMBDisable( void );
+
+/*! \ingroup modbus
+ * \brief The main pooling loop of the Modbus protocol stack.
+ *
+ * This function must be called periodically. The timer interval required
+ * is given by the application dependent Modbus slave timeout. Internally the
+ * function calls xMBPortEventGet() and waits for an event from the receiver or
+ * transmitter state machines. 
+ *
+ * \return If the protocol stack is not in the enabled state the function
+ *   returns eMBErrorCode::MB_EILLSTATE. Otherwise it returns 
+ *   eMBErrorCode::MB_ENOERR.
+ */
+eMBErrorCode    eMBPoll( void );
+
+/*! \ingroup modbus
+ * \brief Configure the slave id of the device.
+ *
+ * This function should be called when the Modbus function <em>Report Slave ID</em>
+ * is enabled ( By defining MB_FUNC_OTHER_REP_SLAVEID_ENABLED in mbconfig.h ).
+ *
+ * \param ucSlaveID Values is returned in the <em>Slave ID</em> byte of the
+ *   <em>Report Slave ID</em> response.
+ * \param xIsRunning If TRUE the <em>Run Indicator Status</em> byte is set to 0xFF.
+ *   otherwise the <em>Run Indicator Status</em> is 0x00.
+ * \param pucAdditional Values which should be returned in the <em>Additional</em>
+ *   bytes of the <em> Report Slave ID</em> response.
+ * \param usAdditionalLen Length of the buffer <code>pucAdditonal</code>.
+ *
+ * \return If the static buffer defined by MB_FUNC_OTHER_REP_SLAVEID_BUF in
+ *   mbconfig.h is to small it returns eMBErrorCode::MB_ENORES. Otherwise
+ *   it returns eMBErrorCode::MB_ENOERR.
+ */
+eMBErrorCode    eMBSetSlaveID( UCHAR ucSlaveID, BOOL xIsRunning,
+                               UCHAR const *pucAdditional,
+                               USHORT usAdditionalLen );
+
+/*! \ingroup modbus
+ * \brief Registers a callback handler for a given function code.
+ *
+ * This function registers a new callback handler for a given function code.
+ * The callback handler supplied is responsible for interpreting the Modbus PDU and
+ * the creation of an appropriate response. In case of an error it should return
+ * one of the possible Modbus exceptions which results in a Modbus exception frame
+ * sent by the protocol stack. 
+ *
+ * \param ucFunctionCode The Modbus function code for which this handler should
+ *   be registers. Valid function codes are in the range 1 to 127.
+ * \param pxHandler The function handler which should be called in case
+ *   such a frame is received. If \c NULL a previously registered function handler
+ *   for this function code is removed.
+ *
+ * \return eMBErrorCode::MB_ENOERR if the handler has been installed. If no
+ *   more resources are available it returns eMBErrorCode::MB_ENORES. In this
+ *   case the values in mbconfig.h should be adjusted. If the argument was not
+ *   valid it returns eMBErrorCode::MB_EINVAL.
+ */
+eMBErrorCode    eMBRegisterCB( UCHAR ucFunctionCode, 
+                               pxMBFunctionHandler pxHandler );
+
+/* ----------------------- Callback -----------------------------------------*/
+
+/*! \defgroup modbus_registers Modbus Registers
+ * \code #include "mb.h" \endcode
+ * The protocol stack does not internally allocate any memory for the
+ * registers. This makes the protocol stack very small and also usable on
+ * low end targets. In addition the values don't have to be in the memory
+ * and could for example be stored in a flash.<br>
+ * Whenever the protocol stack requires a value it calls one of the callback
+ * function with the register address and the number of registers to read
+ * as an argument. The application should then read the actual register values
+ * (for example the ADC voltage) and should store the result in the supplied
+ * buffer.<br>
+ * If the protocol stack wants to update a register value because a write
+ * register function was received a buffer with the new register values is
+ * passed to the callback function. The function should then use these values
+ * to update the application register values.
+ */
+
+/*! \ingroup modbus_registers
+ * \brief Callback function used if the value of a <em>Input Register</em>
+ *   is required by the protocol stack. The starting register address is given
+ *   by \c usAddress and the last register is given by <tt>usAddress +
+ *   usNRegs - 1</tt>.
+ *
+ * \param pucRegBuffer A buffer where the callback function should write
+ *   the current value of the modbus registers to.
+ * \param usAddress The starting address of the register. Input registers
+ *   are in the range 1 - 65535.
+ * \param usNRegs Number of registers the callback function must supply.
+ *
+ * \return The function must return one of the following error codes:
+ *   - eMBErrorCode::MB_ENOERR If no error occurred. In this case a normal
+ *       Modbus response is sent.
+ *   - eMBErrorCode::MB_ENOREG If the application can not supply values
+ *       for registers within this range. In this case a 
+ *       <b>ILLEGAL DATA ADDRESS</b> exception frame is sent as a response.
+ *   - eMBErrorCode::MB_ETIMEDOUT If the requested register block is
+ *       currently not available and the application dependent response
+ *       timeout would be violated. In this case a <b>SLAVE DEVICE BUSY</b>
+ *       exception is sent as a response.
+ *   - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case
+ *       a <b>SLAVE DEVICE FAILURE</b> exception is sent as a response.
+ */
+eMBErrorCode    eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress,
+                               USHORT usNRegs );
+
+/*! \ingroup modbus_registers
+ * \brief Callback function used if a <em>Holding Register</em> value is
+ *   read or written by the protocol stack. The starting register address
+ *   is given by \c usAddress and the last register is given by
+ *   <tt>usAddress + usNRegs - 1</tt>.
+ *
+ * \param pucRegBuffer If the application registers values should be updated the
+ *   buffer points to the new registers values. If the protocol stack needs
+ *   to now the current values the callback function should write them into
+ *   this buffer.
+ * \param usAddress The starting address of the register.
+ * \param usNRegs Number of registers to read or write.
+ * \param eMode If eMBRegisterMode::MB_REG_WRITE the application register 
+ *   values should be updated from the values in the buffer. For example
+ *   this would be the case when the Modbus master has issued an 
+ *   <b>WRITE SINGLE REGISTER</b> command.
+ *   If the value eMBRegisterMode::MB_REG_READ the application should copy 
+ *   the current values into the buffer \c pucRegBuffer.
+ *
+ * \return The function must return one of the following error codes:
+ *   - eMBErrorCode::MB_ENOERR If no error occurred. In this case a normal
+ *       Modbus response is sent.
+ *   - eMBErrorCode::MB_ENOREG If the application can not supply values
+ *       for registers within this range. In this case a 
+ *       <b>ILLEGAL DATA ADDRESS</b> exception frame is sent as a response.
+ *   - eMBErrorCode::MB_ETIMEDOUT If the requested register block is
+ *       currently not available and the application dependent response
+ *       timeout would be violated. In this case a <b>SLAVE DEVICE BUSY</b>
+ *       exception is sent as a response.
+ *   - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case
+ *       a <b>SLAVE DEVICE FAILURE</b> exception is sent as a response.
+ */
+eMBErrorCode    eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress,
+                                 USHORT usNRegs, eMBRegisterMode eMode );
+
+/*! \ingroup modbus_registers
+ * \brief Callback function used if a <em>Coil Register</em> value is
+ *   read or written by the protocol stack. If you are going to use
+ *   this function you might use the functions xMBUtilSetBits(  ) and
+ *   xMBUtilGetBits(  ) for working with bitfields.
+ *
+ * \param pucRegBuffer The bits are packed in bytes where the first coil
+ *   starting at address \c usAddress is stored in the LSB of the
+ *   first byte in the buffer <code>pucRegBuffer</code>.
+ *   If the buffer should be written by the callback function unused
+ *   coil values (I.e. if not a multiple of eight coils is used) should be set
+ *   to zero.
+ * \param usAddress The first coil number.
+ * \param usNCoils Number of coil values requested.
+ * \param eMode If eMBRegisterMode::MB_REG_WRITE the application values should
+ *   be updated from the values supplied in the buffer \c pucRegBuffer.
+ *   If eMBRegisterMode::MB_REG_READ the application should store the current
+ *   values in the buffer \c pucRegBuffer.
+ *
+ * \return The function must return one of the following error codes:
+ *   - eMBErrorCode::MB_ENOERR If no error occurred. In this case a normal
+ *       Modbus response is sent.
+ *   - eMBErrorCode::MB_ENOREG If the application does not map an coils
+ *       within the requested address range. In this case a 
+ *       <b>ILLEGAL DATA ADDRESS</b> is sent as a response.
+ *   - eMBErrorCode::MB_ETIMEDOUT If the requested register block is
+ *       currently not available and the application dependent response
+ *       timeout would be violated. In this case a <b>SLAVE DEVICE BUSY</b>
+ *       exception is sent as a response.
+ *   - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case
+ *       a <b>SLAVE DEVICE FAILURE</b> exception is sent as a response.
+ */
+eMBErrorCode    eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress,
+                               USHORT usNCoils, eMBRegisterMode eMode );
+
+/*! \ingroup modbus_registers
+ * \brief Callback function used if a <em>Input Discrete Register</em> value is
+ *   read by the protocol stack.
+ *
+ * If you are going to use his function you might use the functions
+ * xMBUtilSetBits(  ) and xMBUtilGetBits(  ) for working with bitfields.
+ *
+ * \param pucRegBuffer The buffer should be updated with the current
+ *   coil values. The first discrete input starting at \c usAddress must be
+ *   stored at the LSB of the first byte in the buffer. If the requested number
+ *   is not a multiple of eight the remaining bits should be set to zero.
+ * \param usAddress The starting address of the first discrete input.
+ * \param usNDiscrete Number of discrete input values.
+ * \return The function must return one of the following error codes:
+ *   - eMBErrorCode::MB_ENOERR If no error occurred. In this case a normal
+ *       Modbus response is sent.
+ *   - eMBErrorCode::MB_ENOREG If no such discrete inputs exists.
+ *       In this case a <b>ILLEGAL DATA ADDRESS</b> exception frame is sent 
+ *       as a response.
+ *   - eMBErrorCode::MB_ETIMEDOUT If the requested register block is
+ *       currently not available and the application dependent response
+ *       timeout would be violated. In this case a <b>SLAVE DEVICE BUSY</b>
+ *       exception is sent as a response.
+ *   - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case
+ *       a <b>SLAVE DEVICE FAILURE</b> exception is sent as a response.
+ */
+eMBErrorCode    eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress,
+                                  USHORT usNDiscrete );
+
+#ifdef __cplusplus
+PR_END_EXTERN_C
+#endif
+#endif