Add master support to modbus. From Darcy Gong

14 files changed, 621 insertions, 65 deletions

diff --git a/apps/include/modbus/mb.h b/apps/include/modbus/mb.h
index b8defac8d..cf1e867bb 100644
--- a/apps/include/modbus/mb.h
+++ b/apps/include/modbus/mb.h
@@ -32,25 +32,6 @@
 #ifndef __APPS_INCLUDE_MODBUS_MB_H
 #define __APPS_INCLUDE_MODBUS_MB_H
 
-/****************************************************************************
- * Included Files
- ****************************************************************************/
-
-#include <stdint.h>
-#include <stdbool.h>
-#include <termios.h>
-
-#ifdef __cplusplus
-PR_BEGIN_EXTERN_C
-#endif
-
-#include "mbport.h"
-#include "mbproto.h"
-
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
 /* 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
@@ -75,6 +56,26 @@ PR_BEGIN_EXTERN_C
  *     }
  */
 
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <termios.h>
+
+#ifdef __cplusplus
+PR_BEGIN_EXTERN_C
+#endif
+
+#include "mbport.h"
+#include "mbproto.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+
 /* Use the default Modbus TCP port (502) */
 
 #define MB_TCP_PORT_USE_DEFAULT 0
@@ -319,7 +320,7 @@ eMBErrorCode eMBRegisterCB(uint8_t ucFunctionCode,
  *        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 
+ *       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.
@@ -354,7 +355,7 @@ eMBErrorCode eMBRegInputCB(uint8_t * pucRegBuffer, uint16_t usAddress,
  *        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 
+ *       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.
@@ -390,7 +391,7 @@ eMBErrorCode eMBRegHoldingCB(uint8_t * pucRegBuffer, uint16_t usAddress,
  *        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 
+ *       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.
@@ -421,7 +422,7 @@ eMBErrorCode eMBRegCoilsCB(uint8_t *pucRegBuffer, uint16_t usAddress,
  *       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 
+ *       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.
diff --git a/apps/include/modbus/mb_m.h b/apps/include/modbus/mb_m.h
new file mode 100644
index 000000000..3723b0edd
--- /dev/null
+++ b/apps/include/modbus/mb_m.h
@@ -0,0 +1,465 @@
+/****************************************************************************
+ * apps/include/modbus/mb_m.h
+ *
+ * FreeModbus Library: 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.
+ *
+ ****************************************************************************/
+
+#ifndef __APPS_INCLUDE_MODBUS_MB_M_H
+#define __APPS_INCLUDE_MODBUS_MB_M_H
+
+/* This module defines the interface for the application. It contains
+ * the basic functions and types required to use the Modbus Master protocol stack.
+ * A typical application will want to call eMBMasterInit() 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 eMBMasterPoll() 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 eMBMasterPoll().
+ *
+ *   // Initialize protocol stack in RTU mode for a Master
+ *
+ *   eMBMasterInit(MB_RTU, 38400, MB_PAR_EVEN);
+ *
+ *   // Enable the Modbus Protocol Stack.
+ *
+ *   eMBMasterEnable();
+ *   for(;;)
+ *   {
+ *     // Call the main polling loop of the Modbus Master protocol stack.
+ *
+ *     eMBMasterPoll();
+ *     ...
+ *   }
+ */
+
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <termios.h>
+
+#ifdef __cplusplus
+PR_BEGIN_EXTERN_C
+#endif
+
+#include "mbport.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Use the default Modbus Master TCP port (502) */
+
+#define MB_MASTER_TCP_PORT_USE_DEFAULT 0
+
+/****************************************************************************
+ * Public Type Definitions
+ ****************************************************************************/
+
+/* Error codes used by all function in the Master request. */
+
+typedef enum
+{
+    MB_MRE_NO_ERR,                  /* no error. */
+    MB_MRE_NO_REG,                  /* illegal register address. */
+    MB_MRE_ILL_ARG,                 /* illegal argument. */
+    MB_MRE_REV_DATA,                /* receive data error. */
+    MB_MRE_TIMEDOUT,                /* timeout error occurred. */
+    MB_MRE_MASTER_BUSY,             /* master is busy now. */
+    MB_MRE_EXE_FUN                  /* execute function error. */
+} eMBMasterReqErrCode;
+
+/* TimerMode is Master 3 kind of Timer modes. */
+
+typedef enum
+{
+    MB_TMODE_T35,                   /* Master receive frame T3.5 timeout. */
+    MB_TMODE_RESPOND_TIMEOUT,       /* Master wait respond for slave. */
+    MB_TMODE_CONVERT_DELAY          /* Master sent broadcast ,then delay sometime.*/
+}eMBMasterTimerMode;
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Description:
+ *   Initialize the Modbus Master 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 eMBMasterEnable() has been called.
+ *
+ * Input Parameters:
+ *   eMode If ASCII or RTU mode should be used.
+ *   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.
+ *   ulBaudRate The baudrate. E.g. 19200. Supported baudrates depend
+ *     on the porting layer.
+ *   eParity Parity used for serial transmission.
+ *
+ * Returned Value:
+ *   If no error occurs the function returns eMBErrorCode::MB_ENOERR.
+ *   The protocol is then in the disabled state and ready for activation
+ *   by calling eMBMasterEnable(). Otherwise one of the following error codes
+ *   is returned:
+ *    - eMBErrorCode::MB_EPORTERR IF the porting layer returned an error.
+ *
+ ****************************************************************************/
+
+eMBErrorCode eMBMasterInit(eMBMode eMode, uint8_t ucPort, speed_t ulBaudRate,
+                           eMBParity eParity);
+
+/****************************************************************************
+ * Description:
+ *   Initialize the Modbus Master protocol stack for Modbus TCP.
+ *
+ *   This function initializes the Modbus TCP Module. Please note that
+ *   frame processing is still disabled until eMBEnable() is called.
+ *
+ * Input Parameters:
+ *   usTCPPort The TCP port to listen on.
+ *
+ * Returned Value:
+ *   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 eMBMasterTCPInit(uint16_t usTCPPort);
+
+/****************************************************************************
+ * Description:
+ *   Release resources used by the protocol stack.
+ *
+ *   This function disables the Modbus Master 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.
+ *
+ * Returned Value:
+ *   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 eMBMasterClose(void);
+
+/****************************************************************************
+ * Description:
+ *   Enable the Modbus Master protocol stack.
+ *
+ *   This function enables processing of Modbus Master frames. Enabling the
+ *   protocol stack is only possible if it is in the disabled state.
+ *
+ * Returned Value:
+ *   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 eMBMasterEnable(void);
+
+/****************************************************************************
+ * Description:
+ *   Disable the Modbus Master protocol stack.
+ *
+ *   This function disables processing of Modbus frames.
+ *
+ * Returned Value:
+ *   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 eMBMasterDisable(void);
+
+/****************************************************************************
+ * Description:
+ *   The main pooling loop of the Modbus Master 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 xMBMasterPortEventGet() and waits for an event from
+ *   the receiver or transmitter state machines. 
+ *
+ * Returned Value:
+ *   If the protocol stack is not in the enabled state the function
+ *   returns eMBErrorCode::MB_EILLSTATE. Otherwise it returns 
+ *   eMBErrorCode::MB_ENOERR.
+ *
+ ****************************************************************************/
+
+eMBErrorCode eMBMasterPoll(void);
+
+/****************************************************************************
+ * Description:
+ *   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.
+ *
+ * Input Parameters:
+ *   ucFunctionCode The Modbus function code for which this handler should
+ *     be registers. Valid function codes are in the range 1 to 127.
+ *   pxHandler The function handler which should be called in case
+ *    such a frame is received. If NULL a previously registered function
+ *    handler for this function code is removed.
+ *
+ * Returned Value:
+ *   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 eMBMasterRegisterCB(uint8_t ucFunctionCode,
+                                 pxMBFunctionHandler pxHandler);
+
+/****************************************************************************
+ * Description:
+ *  Callback function used if the value of a Input Register is required by
+ *  the protocol stack. The starting register address is given by usAddress
+ *  and the last register is given by usAddress + usNRegs - 1.
+ *
+ *  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.
+ *
+ * Input Parameters:
+ *   pucRegBuffer A buffer where the callback function should write
+ *     the current value of the modbus registers to.
+ *   usAddress The starting address of the register. Input registers
+ *     are in the range 1 - 65535.
+ *   usNRegs Number of registers the callback function must supply.
+ *
+ * Returned Value:
+ *   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 eMBMasterRegInputCB(uint8_t *pucRegBuffer, uint16_t usAddress,
+                                 uint16_t usNRegs);
+
+/****************************************************************************
+ * Description:
+ *  Callback function used if a Holding Register value is
+ *   read or written by the protocol stack. The starting register address
+ *   is given by usAddress and the last register is given by
+ *   usAddress + usNRegs - 1.
+ *
+ * Input Parameters:
+ *   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.
+ *   usAddress The starting address of the register.
+ *   usNRegs Number of registers to read or write.
+ *   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 pucRegBuffer.
+ *
+ * Returned Value:
+ *   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 eMBMasterRegHoldingCB(uint8_t *pucRegBuffer, uint16_t usAddress,
+                                   uint16_t usNRegs, eMBRegisterMode eMode);
+
+/****************************************************************************
+ * Description:
+ *  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.
+ *
+ * Input Parameters:
+ *   pucRegBuffer The bits are packed in bytes where the first coil
+ *     starting at address 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.
+ *   usAddress The first coil number.
+ *   usNCoils Number of coil values requested.
+ *   eMode If eMBRegisterMode::MB_REG_WRITE the application values should
+ *     be updated from the values supplied in the buffer pucRegBuffer.
+ *     If eMBRegisterMode::MB_REG_READ the application should store the
+ *     current values in the buffer pucRegBuffer.
+ *
+ * Returned Value:
+ *   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 eMBMasterRegCoilsCB(uint8_t *pucRegBuffer, uint16_t usAddress,
+                                 uint16_t usNCoils, eMBRegisterMode eMode);
+
+/****************************************************************************
+ * Description:
+ *  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.
+ *
+ * Input Parameters:
+ *   pucRegBuffer The buffer should be updated with the current
+ *     coil values. The first discrete input starting at 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.
+ *   usAddress The starting address of the first discrete input.
+ *   usNDiscrete Number of discrete input values.
+ *
+ * Returned Value:
+ *   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 eMBMasterRegDiscreteCB(uint8_t *pucRegBuffer, uint16_t usAddress,
+                                    uint16_t usNDiscrete);
+
+/****************************************************************************
+ * Description:
+ * These Modbus functions are called for user when Modbus run in Master Mode.
+ *
+ ****************************************************************************/
+
+eMBMasterReqErrCode eMBMasterReqReadInputRegister(uint8_t ucSndAddr,
+  uint16_t usRegAddr, uint16_t usNRegs, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqWriteHoldingRegister(uint8_t ucSndAddr,
+  uint16_t usRegAddr, uint16_t usRegData, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqWriteMultipleHoldingRegister(uint8_t ucSndAddr,
+  uint16_t usRegAddr, uint16_t usNRegs, uint16_t *pusDataBuffer,
+  uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqReadHoldingRegister(uint8_t ucSndAddr,
+  uint16_t usRegAddr, uint16_t usNRegs, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqReadWriteMultipleHoldingRegister(uint8_t ucSndAddr,
+  uint16_t usReadRegAddr, uint16_t usNReadRegs, uint16_t *pusDataBuffer,
+  uint16_t usWriteRegAddr, uint16_t usNWriteRegs, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqReadCoils(uint8_t ucSndAddr,
+  uint16_t usCoilAddr, uint16_t usNCoils, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqWriteCoil(uint8_t ucSndAddr,
+  uint16_t usCoilAddr, uint16_t usCoilData, uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqWriteMultipleCoils(uint8_t ucSndAddr,
+  uint16_t usCoilAddr, uint16_t usNCoils, uint8_t *pucDataBuffer,
+  uint32_t lTimeOut);
+eMBMasterReqErrCode eMBMasterReqReadDiscreteInputs(uint8_t ucSndAddr,
+  uint16_t usDiscreteAddr, uint16_t usNDiscreteIn, uint32_t lTimeOut);
+
+eMBException eMBMasterFuncReportSlaveID(uint8_t *pucFrame, uint16_t *usLen);
+eMBException eMBMasterFuncReadInputRegister(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncReadHoldingRegister(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncWriteHoldingRegister(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncWriteMultipleHoldingRegister(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncReadCoils(uint8_t *pucFrame, uint16_t *usLen);
+eMBException eMBMasterFuncWriteCoil(uint8_t *pucFrame, uint16_t *usLen);
+eMBException eMBMasterFuncWriteMultipleCoils(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncReadDiscreteInputs(uint8_t *pucFrame,
+  uint16_t *usLen);
+eMBException eMBMasterFuncReadWriteMultipleHoldingRegister(uint8_t *pucFrame,
+  uint16_t *usLen);
+
+/* These functions are interface for Modbus Master */
+
+void vMBMasterGetPDUSndBuf(uint8_t **pucFrame);
+uint8_t ucMBMasterGetDestAddress(void);
+void vMBMasterSetDestAddress(uint8_t Address);
+bool xMBMasterGetCBRunInMasterMode(void);
+void vMBMasterSetCBRunInMasterMode(bool IsMasterMode);
+uint16_t usMBMasterGetPDUSndLength(void);
+void vMBMasterSetPDUSndLength(uint16_t SendPDULength);
+void vMBMasterSetCurTimerMode(eMBMasterTimerMode eMBTimerMode);
+bool xMBMasterRequestIsBroadcast(void);
+eMBMasterErrorEventType eMBMasterGetErrorType(void);
+void vMBMasterSetErrorType(eMBMasterErrorEventType errorType);
+eMBMasterReqErrCode eMBMasterWaitRequestFinish(void);
+
+#ifdef __cplusplus
+PR_END_EXTERN_C
+#endif
+
+#endif /* __APPS_INCLUDE_MODBUS_MB_M_H */
diff --git a/apps/include/modbus/mbport.h b/apps/include/modbus/mbport.h
index cfb1838ba..626469981 100644
--- a/apps/include/modbus/mbport.h
+++ b/apps/include/modbus/mbport.h
@@ -55,6 +55,26 @@ typedef enum
   EV_FRAME_SENT               /* Frame sent. */
 } eMBEventType;
 
+typedef enum
+{
+  EV_MASTER_READY                  = 1<<0,  /* Startup finished. */
+  EV_MASTER_FRAME_RECEIVED         = 1<<1,  /* Frame received. */
+  EV_MASTER_EXECUTE                = 1<<2,  /* Execute function. */
+  EV_MASTER_FRAME_SENT             = 1<<3,  /* Frame sent. */
+  EV_MASTER_ERROR_PROCESS          = 1<<4,  /* Frame error process. */
+  EV_MASTER_PROCESS_SUCESS         = 1<<5,  /* Request process success. */
+  EV_MASTER_ERROR_RESPOND_TIMEOUT  = 1<<6,  /* Request respond timeout. */
+  EV_MASTER_ERROR_RECEIVE_DATA     = 1<<7,  /* Request receive data error. */
+  EV_MASTER_ERROR_EXECUTE_FUNCTION = 1<<8   /* Request execute function error. */
+} eMBMasterEventType;
+
+typedef enum
+{
+  EV_ERROR_RESPOND_TIMEOUT,   /* Slave respond timeout. */
+  EV_ERROR_RECEIVE_DATA,      /* Receive frame data erroe. */
+  EV_ERROR_EXECUTE_FUNCTION   /* Execute function error. */
+} eMBMasterErrorEventType;
+
 /* Parity used for characters in serial mode.
  *
  * The parity which should be applied to the characters sent over the serial
@@ -84,9 +104,13 @@ typedef enum
  * currently blocked on the eventqueue.
  */
 
-extern  bool(*pxMBFrameCBByteReceived)(void);
-extern  bool(*pxMBFrameCBTransmitterEmpty)(void);
-extern  bool(*pxMBPortCBTimerExpired)(void);
+extern bool(*pxMBFrameCBByteReceived)(void);
+extern bool(*pxMBFrameCBTransmitterEmpty)(void);
+extern bool(*pxMBPortCBTimerExpired)(void);
+
+extern bool(*pxMBMasterFrameCBByteReceived)(void);
+extern bool(*pxMBMasterFrameCBTransmitterEmpty)(void);
+extern bool(*pxMBMasterPortCBTimerExpired)(void);
 
 /****************************************************************************
  * Public Function Prototypes
@@ -96,7 +120,14 @@ extern  bool(*pxMBPortCBTimerExpired)(void);
 
 bool xMBPortEventInit(void);
 bool xMBPortEventPost(eMBEventType eEvent);
-bool xMBPortEventGet(/*@out@ */ eMBEventType * eEvent);
+bool xMBPortEventGet(eMBEventType *eEvent);
+
+bool xMBMasterPortEventInit(void);
+bool xMBMasterPortEventPost(eMBMasterEventType eEvent);
+bool xMBMasterPortEventGet(eMBMasterEventType * eEvent);
+void vMBMasterOsResInit(void);
+bool xMBMasterRunResTake(int32_t time);
+void vMBMasterRunResRelease(void);
 
 /* Serial port functions */
 
@@ -108,6 +139,14 @@ void vMBPortSerialEnable(bool xRxEnable, bool xTxEnable);
 bool xMBPortSerialGetByte(int8_t * pucByte);
 bool xMBPortSerialPutByte(int8_t ucByte);
 
+bool xMBMasterPortSerialInit(uint8_t ucPort, speed_t ulBaudRate,
+                             uint8_t ucDataBits, eMBParity eParity);
+void vMBMasterPortClose(void);
+void xMBMasterPortSerialClose(void);
+void vMBMasterPortSerialEnable(bool xRxEnable, bool xTxEnable);
+bool xMBMasterPortSerialGetByte(int8_t * pucByte);
+bool xMBMasterPortSerialPutByte(int8_t ucByte);
+
 /* Timers functions */
 
 bool xMBPortTimersInit(uint16_t usTimeOut50us);
@@ -116,6 +155,23 @@ void vMBPortTimersEnable(void);
 void vMBPortTimersDisable(void);
 void vMBPortTimersDelay(uint16_t usTimeOutMS);
 
+bool xMBMasterPortTimersInit(uint16_t usTimeOut50us);
+void xMBMasterPortTimersClose(void);
+void vMBMasterPortTimersT35Enable(void);
+void vMBMasterPortTimersConvertDelayEnable(void);
+void vMBMasterPortTimersRespondTimeoutEnable(void);
+void vMBMasterPortTimersDisable(void);
+
+/* Callback for the master error process */
+
+void vMBMasterErrorCBRespondTimeout(uint8_t ucDestAddress, const uint8_t *pucPDUData,
+                                    uint16_t ucPDULength);
+void vMBMasterErrorCBReceiveData(uint8_t ucDestAddress, const uint8_t *pucPDUData,
+                                 uint16_t ucPDULength);
+void vMBMasterErrorCBExecuteFunction(uint8_t ucDestAddress, const uint8_t *pucPDUData,
+                                     uint16_t ucPDULength);
+void vMBMasterCBRequestScuuess(void);
+
 #ifdef CONFIG_MB_TCP_ENABLED
 /* TCP port function */
 
diff --git a/apps/modbus/Kconfig b/apps/modbus/Kconfig
index c62ff5c88..e2d6db61a 100644
--- a/apps/modbus/Kconfig
+++ b/apps/modbus/Kconfig
@@ -13,10 +13,20 @@ config MB_ASCII_ENABLED
 	bool "Modbus ASCII support"
 	default y
 
+config MB_ASCII_MASTER
+	bool "Modbus ASCII master"
+	default n
+	depends on MB_ASCII_ENABLED
+
 config MB_RTU_ENABLED
 	bool "Modbus RTU support"
 	default y
 
+config MB_RTU_MASTER
+	bool "Modbus RTU master"
+	default n
+	depends on MB_RTU_ENABLED
+
 config MB_TCP_ENABLED
 	bool "Modbus TCP support"
 	default y
@@ -41,6 +51,7 @@ config MB_ASCII_TIMEOUT_SEC
 		a configuration option. It should be set to the maximum expected delay
 		time of the network.
 
+
 config MB_ASCII_TIMEOUT_WAIT_BEFORE_SEND_MS
 	int "Timeout to wait before sending"
 	depends on MB_ASCII_ENABLED
@@ -137,4 +148,14 @@ config MB_FUNC_READWRITE_HOLDING_ENABLED
 	---help---
 		If the Read/Write Multiple Registers function should be enabled.
 
+if MB_ASCII_MASTER || MB_RTU_MASTER
+
+config MB_MASTER_TOTAL_SLAVE_NUM
+	int "Total number slaves"
+	default 16
+	---help---
+		The total slaves in Modbus Master system. Default 16.
+		NOTE: The slave ID must be continuous from 1.
+
+endif # MB_ASCII_MASTER || MB_RTU_MASTER
 endif # MODBUS
diff --git a/apps/modbus/README.txt b/apps/modbus/README.txt
index 7ce674a3c..5a1f7b209 100644
--- a/apps/modbus/README.txt
+++ b/apps/modbus/README.txt
@@ -5,9 +5,9 @@ This directory contains a port of last open source version of FreeModBus
 (BSD license).  The code in this directory is a subset of FreeModBus version
 1.5.0 (June 6, 2010) that can be downloaded in its entirety from http://developer.berlios.de/project/showfiles.php?group_id=6120.
 
-NOTE: There are extensions to support RTU master mode available here:
-https://github.com/armink/FreeModbus_Slave-Master-RTT-STM32, author:
-Armink(383016632@qq.com)
+Includes extensions to support RTU master mode by Armink(383016632@qq.com):
+https://github.com/armink/FreeModbus_Slave-Master-RTT-STM32.  Ported to
+NuttX by Darcy Gong.
 
 Directory Structure/Relation to freemodbus-v1.5.0
 -------------------------------------------------
@@ -62,7 +62,9 @@ The NuttX-named configuration options that are available include:
 
     CONFIG_MODBUS - General ModBus support
     CONFIG_MB_ASCII_ENABLED - Modbus ASCII support
+    CONFIG_MB_ASCII_MASTER - Modbus ASCII master support
     CONFIG_MB_RTU_ENABLED - Modbus RTU support
+    CONFIG_MB_RTU_MASTER - Modbus RTU master support
     CONFIG_MB_TCP_ENABLED - Modbus TCP support
     CONFIG_MB_ASCII_TIMEOUT_SEC - Character timeout value for Modbus ASCII. The
       character timeout value is not fixed for Modbus ASCII and is therefore
diff --git a/apps/modbus/functions/Make.defs b/apps/modbus/functions/Make.defs
index d7888e8d7..1e40d45d1 100644
--- a/apps/modbus/functions/Make.defs
+++ b/apps/modbus/functions/Make.defs
@@ -35,7 +35,14 @@
 
 CSRCS += mbfunccoils.c mbfuncdiag.c mbfuncdisc.c mbfuncholding.c
 CSRCS += mbfuncinput.c mbfuncother.c mbutils.c
+
+ifeq ($(CONFIG_MB_ASCII_MASTER),y)
+CSRCS += mbfunccoils_m.c mbfuncdisc_m.c mbfuncholding_m.c mbfuncinput_m.c
+else
+ifeq ($(CONFIG_MB_RTU_MASTER),y)
 CSRCS += mbfunccoils_m.c mbfuncdisc_m.c mbfuncholding_m.c mbfuncinput_m.c
+endif
+endif
 
 DEPPATH += --dep-path functions
 VPATH += :functions
diff --git a/apps/modbus/functions/mbfunccoils.c b/apps/modbus/functions/mbfunccoils.c
index 896d37aab..9be42999d 100644
--- a/apps/modbus/functions/mbfunccoils.c
+++ b/apps/modbus/functions/mbfunccoils.c
@@ -42,6 +42,7 @@
 #include <apps/modbus/mb.h>
 #include <apps/modbus/mbframe.h>
 #include <apps/modbus/mbproto.h>
+#include <apps/modbus/mbport.h>
 
 /****************************************************************************
  * Pre-processor Definitions
diff --git a/apps/modbus/functions/mbfunccoils_m.c b/apps/modbus/functions/mbfunccoils_m.c
index e34a940af..1bc5f46c4 100644
--- a/apps/modbus/functions/mbfunccoils_m.c
+++ b/apps/modbus/functions/mbfunccoils_m.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/modbus/functions/mbfunccoils_m.c
  * 
- * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
+ * FreeModbus Library: A portable Modbus implementation for Modbus ASCII/RTU.
  * Copyright (C) 2013 Armink <armink.ztl@gmail.com>
  * All rights reserved.
  *
@@ -43,6 +43,7 @@
 #include <apps/modbus/mb_m.h>
 #include <apps/modbus/mbframe.h>
 #include <apps/modbus/mbproto.h>
+#include <apps/modbus/mbport.h>
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -82,7 +83,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  * Public Functions
  ****************************************************************************/
 
-#if MB_MASTER_RTU_ENABLED > 0 || MB_MASTER_ASCII_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER) || defined(CONFIG_MB_ASCII_MASTER)
 
 /****************************************************************************
  * Description:
@@ -99,7 +100,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  *
  ****************************************************************************/
 
-#if MB_FUNC_READ_COILS_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_READ_COILS_ENABLED
 eMBMasterReqErrCode eMBMasterReqReadCoils(uint8_t ucSndAddr,
                                           uint16_t usCoilAddr,
                                           uint16_t usNCoils,
@@ -108,7 +109,7 @@ eMBMasterReqErrCode eMBMasterReqReadCoils(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
@@ -229,7 +230,7 @@ eMBException eMBMasterFuncReadCoils(uint8_t *pucFrame, uint16_t *usLen)
  *
  ****************************************************************************/
 
-#if MB_FUNC_WRITE_COIL_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_WRITE_COIL_ENABLED
 eMBMasterReqErrCode eMBMasterReqWriteCoil(uint8_t ucSndAddr,
                                           uint16_t usCoilAddr,
                                           uint16_t usCoilData,
@@ -238,7 +239,7 @@ eMBMasterReqErrCode eMBMasterReqWriteCoil(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
@@ -341,7 +342,7 @@ eMBException eMBMasterFuncWriteCoil(uint8_t *pucFrame, uint16_t *usLen)
  *
  ****************************************************************************/
 
-#if MB_FUNC_WRITE_MULTIPLE_COILS_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_WRITE_MULTIPLE_COILS_ENABLED
 eMBMasterReqErrCode eMBMasterReqWriteMultipleCoils(uint8_t ucSndAddr,
                                                    uint16_t usCoilAddr,
                                                    uint16_t usNCoils,
@@ -353,7 +354,7 @@ eMBMasterReqErrCode eMBMasterReqWriteMultipleCoils(uint8_t ucSndAddr,
   uint8_t ucByteCount;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
diff --git a/apps/modbus/functions/mbfuncdisc_m.c b/apps/modbus/functions/mbfuncdisc_m.c
index 7618dd9a5..7392896de 100644
--- a/apps/modbus/functions/mbfuncdisc_m.c
+++ b/apps/modbus/functions/mbfuncdisc_m.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/modbus/functions/mbfuncdisc_m.c
  * 
- * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
+ * FreeModbus Library: A portable Modbus implementation for Modbus ASCII/RTU.
  * Copyright (C) 2013 Armink <armink.ztl@gmail.com>
  * All rights reserved.
  *
@@ -65,7 +65,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  * Public Functions
  ****************************************************************************/
 
-#if MB_MASTER_RTU_ENABLED > 0 || MB_MASTER_ASCII_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER) || defined(CONFIG_MB_ASCII_MASTER)
 
 /****************************************************************************
  * Description:
@@ -82,7 +82,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  *
  ****************************************************************************/
 
-#if MB_FUNC_READ_DISCRETE_INPUTS_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_READ_DISCRETE_INPUTS_ENABLED
 eMBMasterReqErrCode eMBMasterReqReadDiscreteInputs(uint8_t ucSndAddr,
                                                    uint16_t usDiscreteAddr,
                                                    uint16_t usNDiscreteIn,
@@ -91,7 +91,7 @@ eMBMasterReqErrCode eMBMasterReqReadDiscreteInputs(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
diff --git a/apps/modbus/functions/mbfuncholding_m.c b/apps/modbus/functions/mbfuncholding_m.c
index d5e802700..7f4269e7c 100644
--- a/apps/modbus/functions/mbfuncholding_m.c
+++ b/apps/modbus/functions/mbfuncholding_m.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/modbus/functions/mbfuncholding_m.c
  * 
- * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
+ * FreeModbus Library: A portable Modbus implementation for Modbus ASCII/RTU.
  * Copyright (C) 2013 Armink <armink.ztl@gmail.com>
  * All rights reserved.
  *
@@ -94,7 +94,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  * Public Functions
  ****************************************************************************/
 
-#if MB_MASTER_RTU_ENABLED > 0 || MB_MASTER_ASCII_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER) || defined(CONFIG_MB_ASCII_MASTER)
 
 /****************************************************************************
  * Description:
@@ -111,7 +111,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  *
  ****************************************************************************/
 
-#if MB_FUNC_WRITE_HOLDING_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_WRITE_HOLDING_ENABLED
 eMBMasterReqErrCode eMBMasterReqWriteHoldingRegister(uint8_t ucSndAddr,
                                                      uint16_t usRegAddr,
                                                      uint16_t usRegData,
@@ -120,7 +120,7 @@ eMBMasterReqErrCode eMBMasterReqWriteHoldingRegister(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
@@ -195,7 +195,7 @@ eMBException eMBMasterFuncWriteHoldingRegister(uint8_t *pucFrame,
  *
  ****************************************************************************/
 
-#if MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED
 eMBMasterReqErrCode
   eMBMasterReqWriteMultipleHoldingRegister(uint8_t ucSndAddr,
                                            uint16_t usRegAddr,
@@ -207,7 +207,7 @@ eMBMasterReqErrCode
   uint16_t usRegIndex = 0;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
@@ -313,7 +313,7 @@ eMBException eMBMasterFuncWriteMultipleHoldingRegister(uint8_t *pucFrame,
  *
  ****************************************************************************/
 
-#if MB_FUNC_READ_HOLDING_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_READ_HOLDING_ENABLED
 eMBMasterReqErrCode eMBMasterReqReadHoldingRegister(uint8_t ucSndAddr,
                                                     uint16_t usRegAddr,
                                                     uint16_t usNRegs,
@@ -322,7 +322,7 @@ eMBMasterReqErrCode eMBMasterReqReadHoldingRegister(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
@@ -429,7 +429,7 @@ eMBException eMBMasterFuncReadHoldingRegister(uint8_t *pucFrame,
  *
  ****************************************************************************/
 
-#if MB_FUNC_READWRITE_HOLDING_ENABLED > 0
+#ifdef CONFIG_MB_FUNC_READWRITE_HOLDING_ENABLED
 eMBMasterReqErrCode
   eMBMasterReqReadWriteMultipleHoldingRegister(uint8_t ucSndAddr,
                                                uint16_t usReadRegAddr,
@@ -443,7 +443,7 @@ eMBMasterReqErrCode
   uint16_t usRegIndex = 0;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
diff --git a/apps/modbus/functions/mbfuncinput_m.c b/apps/modbus/functions/mbfuncinput_m.c
index 475cdca56..26c5f96b6 100644
--- a/apps/modbus/functions/mbfuncinput_m.c
+++ b/apps/modbus/functions/mbfuncinput_m.c
@@ -1,6 +1,6 @@
 /****************************************************************************
  * apps/modbus/functions/mbfuncinput_m.c
- * 
+ *
  * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
  * Copyright (C) 2013 Armink <armink.ztl@gmail.com>
  * All rights reserved.
@@ -67,7 +67,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  * Public Functions
  ****************************************************************************/
 
-#if MB_MASTER_RTU_ENABLED > 0 || MB_MASTER_ASCII_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER) || defined(CONFIG_MB_ASCII_MASTER)
 
 /****************************************************************************
  * Description:
@@ -84,7 +84,7 @@ eMBException prveMBError2Exception(eMBErrorCode eErrorCode);
  *
  ****************************************************************************/
 
-#if MB_FUNC_READ_INPUT_ENABLED > 0
+#if defined(CONFIG_MB_FUNC_READ_INPUT_ENABLED)
 eMBMasterReqErrCode eMBMasterReqReadInputRegister(uint8_t ucSndAddr,
                                                   uint16_t usRegAddr,
                                                   uint16_t usNRegs,
@@ -93,7 +93,7 @@ eMBMasterReqErrCode eMBMasterReqReadInputRegister(uint8_t ucSndAddr,
   uint8_t *ucMBFrame;
   eMBMasterReqErrCode eErrStatus = MB_MRE_NO_ERR;
 
-  if (ucSndAddr > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSndAddr > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       eErrStatus = MB_MRE_ILL_ARG;
     }
diff --git a/apps/modbus/rtu/Make.defs b/apps/modbus/rtu/Make.defs
index f83176f63..681b90ed8 100644
--- a/apps/modbus/rtu/Make.defs
+++ b/apps/modbus/rtu/Make.defs
@@ -36,7 +36,9 @@
 ifeq ($(CONFIG_MB_RTU_ENABLED),y)
 
 CSRCS += mbcrc.c mbrtu.c
+ifeq ($(CONFIG_MB_RTU_MASTER),y)
 CSRCS += mbrtu_m.c
+endif
 
 DEPPATH += --dep-path rtu
 VPATH += :rtu
diff --git a/apps/modbus/rtu/mbrtu.h b/apps/modbus/rtu/mbrtu.h
index 8ab0a982d..7187d8aec 100644
--- a/apps/modbus/rtu/mbrtu.h
+++ b/apps/modbus/rtu/mbrtu.h
@@ -37,7 +37,7 @@ PR_BEGIN_EXTERN_C
 #endif
 
 /****************************************************************************
- * Global Function Prototypes
+ * Public Function Prototypes
  ****************************************************************************/
 
 eMBErrorCode eMBRTUInit(uint8_t slaveAddress, uint8_t ucPort,
@@ -53,7 +53,7 @@ bool xMBRTUTransmitFSM(void);
 bool xMBRTUTimerT15Expired(void);
 bool xMBRTUTimerT35Expired(void);
 
-#if MB_MASTER_RTU_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER)
 eMBErrorCode eMBMasterRTUInit(uint8_t ucPort, speed_t ulBaudRate,
                               eMBParity eParity);
 void eMBMasterRTUStart(void);
diff --git a/apps/modbus/rtu/mbrtu_m.c b/apps/modbus/rtu/mbrtu_m.c
index 1110a4410..78df23ad1 100644
--- a/apps/modbus/rtu/mbrtu_m.c
+++ b/apps/modbus/rtu/mbrtu_m.c
@@ -1,6 +1,6 @@
 /****************************************************************************
  * apps/modbus/rtu/mbrtu_m.c
- * 
+ *
  * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
  * Copyright (c) 2013 China Beijing Armink <armink.ztl@gmail.com>
  * All rights reserved.
@@ -48,7 +48,7 @@
 
 #include <apps/modbus/mbport.h>
 
-#if MB_MASTER_RTU_ENABLED > 0
+#if defined(CONFIG_RTU_ASCII_MASTER)
 
 /****************************************************************************
  * Included Files
@@ -132,7 +132,7 @@ eMBErrorCode eMBMasterRTUInit(uint8_t ucPort, speed_t ulBaudRate,
         }
       else
         {
-          /* The timer reload value for a character is given by: ChTimeValue = 
+          /* The timer reload value for a character is given by: ChTimeValue =
            * Ticks_per_1s / ( Baudrate / 11 ) = 11 * Ticks_per_1s / Baudrate =
            * 220000 / Baudrate The reload for t3.5 is 1.5 times this value and
            * similary for t3.5.
@@ -155,7 +155,7 @@ void eMBMasterRTUStart(void)
 {
   ENTER_CRITICAL_SECTION();
 
-  /* Initially the receiver is in the state STATE_M_RX_INIT. we start the timer 
+  /* Initially the receiver is in the state STATE_M_RX_INIT. we start the timer
    * and if no character is received within t3.5 we change to STATE_M_RX_IDLE.
    * This makes sure that we delay startup of the modbus protocol stack until
    * the bus is free.
@@ -222,14 +222,14 @@ eMBErrorCode eMBMasterRTUSend(uint8_t ucSlaveAddress, const uint8_t *pucFrame,
   eMBErrorCode eStatus = MB_ENOERR;
   uint16_t usCRC16;
 
-  if (ucSlaveAddress > MB_MASTER_TOTAL_SLAVE_NUM)
+  if (ucSlaveAddress > CONFIG_MB_MASTER_TOTAL_SLAVE_NUM)
     {
       return MB_EINVAL;
     }
 
   ENTER_CRITICAL_SECTION();
 
-  /* Check if the receiver is still in idle state. If not we where to slow with 
+  /* Check if the receiver is still in idle state. If not we where to slow with
    * processing the received frame and the master sent another frame on the
    * network. We have to abort sending the frame.
    */
@@ -304,7 +304,7 @@ bool xMBMasterRTUReceiveFSM(void)
        */
 
     case STATE_M_RX_IDLE:
-      /* In time of respond timeout,the receiver receive a frame. Disable timer 
+      /* In time of respond timeout,the receiver receive a frame. Disable timer
        * of respond timeout and change the transmitter state to idle.
        */