/* * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU. * Copyright (c) 2006 Christian Walter * 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 #include #include #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. B19200. 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, uint8_t ucSlaveAddress, uint8_t ucPort, speed_t 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( uint16_t 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 Report Slave ID * is enabled (By defining CONFIG_MB_FUNC_OTHER_REP_SLAVEID_ENABLED in .config ). * * \param ucSlaveID Values is returned in the Slave ID byte of the * Report Slave ID response. * \param xIsRunning If true the Run Indicator Status byte is set to 0xFF. * otherwise the Run Indicator Status is 0x00. * \param pucAdditional Values which should be returned in the Additional * bytes of the Report Slave ID response. * \param usAdditionalLen Length of the buffer pucAdditonal. * * \return If the static buffer defined by CONFIG_MB_FUNC_OTHER_REP_SLAVEID_BUF * is too small it returns eMBErrorCode::MB_ENORES. Otherwise * it returns eMBErrorCode::MB_ENOERR. */ eMBErrorCode eMBSetSlaveID( uint8_t ucSlaveID, bool xIsRunning, uint8_t const *pucAdditional, uint16_t 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 config.h should be adjusted. If the argument was not * valid it returns eMBErrorCode::MB_EINVAL. */ eMBErrorCode eMBRegisterCB( uint8_t 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.
* 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.
* 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 Input Register * is required by the protocol stack. The starting register address is given * by \c usAddress and the last register is given by usAddress + * usNRegs - 1. * * \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 * ILLEGAL DATA ADDRESS 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 SLAVE DEVICE BUSY * exception is sent as a response. * - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case * a SLAVE DEVICE FAILURE exception is sent as a response. */ eMBErrorCode eMBRegInputCB( uint8_t * pucRegBuffer, uint16_t usAddress, uint16_t usNRegs ); /*! \ingroup modbus_registers * \brief Callback function used if a Holding Register 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 * usAddress + usNRegs - 1. * * \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 * WRITE SINGLE REGISTER 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 * ILLEGAL DATA ADDRESS 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 SLAVE DEVICE BUSY * exception is sent as a response. * - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case * a SLAVE DEVICE FAILURE exception is sent as a response. */ eMBErrorCode eMBRegHoldingCB( uint8_t * pucRegBuffer, uint16_t usAddress, uint16_t usNRegs, eMBRegisterMode eMode ); /*! \ingroup modbus_registers * \brief Callback function used if a Coil Register 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 pucRegBuffer. * 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 * ILLEGAL DATA ADDRESS 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 SLAVE DEVICE BUSY * exception is sent as a response. * - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case * a SLAVE DEVICE FAILURE exception is sent as a response. */ eMBErrorCode eMBRegCoilsCB( uint8_t * pucRegBuffer, uint16_t usAddress, uint16_t usNCoils, eMBRegisterMode eMode ); /*! \ingroup modbus_registers * \brief Callback function used if a Input Discrete Register 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 ILLEGAL DATA ADDRESS 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 SLAVE DEVICE BUSY * exception is sent as a response. * - eMBErrorCode::MB_EIO If an unrecoverable error occurred. In this case * a SLAVE DEVICE FAILURE exception is sent as a response. */ eMBErrorCode eMBRegDiscreteCB( uint8_t * pucRegBuffer, uint16_t usAddress, uint16_t usNDiscrete ); #ifdef __cplusplus PR_END_EXTERN_C #endif #endif