stm32--free modbus 1.5.0移植（作为从机）

添加文件

获取原始free modbus library（官网）
将...\freemodbus-v1.5.0\demo\BARE中的所有文件复制到...\freemodbus-v1.5.0\modbus中，修改demo.c文件名为user_mb_app.c
将...\freemodbus-v1.5.0\modbus中的所有.c文件全部添加到项目中
在项目路径中添加所有.c、.h文件路径

添加完成后项目结构图：

移植修改

需要修改的文件：

port.h：补全开关总中断的宏定义、宏定义串口和定时器

#define ENTER_CRITICAL_SECTION( )   __set_PRIMASK(1); //关闭中断
#define EXIT_CRITICAL_SECTION( )    __set_PRIMASK(0); //开启中断

portserial.c：补全串口相关函数（串口中断使能选择、串口初始化、发送1字节、接收1字节、串口中断服务函数）

注意事项：
1. 使能中断：发送中断应使用TC而非TXE，否则可能会出现最后一个字节不能成功发送的情况。此外由于是用485发送，所以在使能中断时，应同时转换485收发转换引脚。使能中断前，应判断对应的标志位是否为1，为1则清除该标志位。
2. 串口初始化：初始化前用USART_DeInit重置寄存器；引脚初始化(GPIO)->串口初始化(USART)->中断初始化(NVIC)；参数中的ucPORT和eParity都应该忽略。
3. 发送1字节：不用循环等待发送完成，因为已经有发送完成中断了
4. 串口中断服务函数：在stm32f0xx_it.c中添加USART3_4_IRQHandler函数，跳转到本文件中的prvvModbusUARTISR函数。

  1 /*
  2  * FreeModbus Libary: BARE Port
  3  * Copyright (C) 2006 Christian Walter <wolti@sil.at>
  4  *
  5  * This library is free software; you can redistribute it and/or
  6  * modify it under the terms of the GNU Lesser General Public
  7  * License as published by the Free Software Foundation; either
  8  * version 2.1 of the License, or (at your option) any later version.
  9  *
 10  * This library is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 13  * Lesser General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU Lesser General Public
 16  * License along with this library; if not, write to the Free Software
 17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 18  *
 19  * File: $Id: portserial.c,v 1.1 2006/08/22 21:35:13 wolti Exp $
 20  */
 21 
 22 #include "port.h"
 23 
 24 /* ----------------------- Modbus includes ----------------------------------*/
 25 #include "mb.h"
 26 #include "mbport.h"
 27 
 28 /* ----------------------- static functions ---------------------------------*/
 29 static void prvvUARTTxReadyISR( void );
 30 static void prvvUARTRxISR( void );
 31 
 32 #define MODBUS_SEND()     (GPIO_SetBits(MODBUS_USART_CTRL_PORT, MODBUS_USART_CTRL_PIN))
 33 #define MODBUS_RECIEVE()  (GPIO_ResetBits(MODBUS_USART_CTRL_PORT, MODBUS_USART_CTRL_PIN))
 34 
 35 /* ----------------------- Start implementation -----------------------------*/
 36 void
 37 vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )
 38 {
 39   /* If xRXEnable enable serial receive interrupts. If xTxENable enable
 40    * transmitter empty interrupts.
 41    */
 42   if(xRxEnable==TRUE) {
 43     MODBUS_RECIEVE();
 44     if(USART_GetFlagStatus(MODBUS_USART, USART_FLAG_RXNE) == SET) {
 45       USART_ClearFlag(MODBUS_USART, USART_FLAG_RXNE);
 46     }
 47     USART_ITConfig(MODBUS_USART, USART_IT_RXNE, ENABLE);
 48   } else if(xRxEnable == FALSE) {
 49     MODBUS_SEND();
 50     USART_ITConfig(MODBUS_USART, USART_IT_RXNE, DISABLE);
 51   }
 52   
 53   if(xTxEnable==TRUE) {
 54     MODBUS_SEND();
 55     if(USART_GetFlagStatus(MODBUS_USART, USART_FLAG_TC) == SET) {
 56       USART_ClearFlag(MODBUS_USART, USART_FLAG_TC);
 57     }
 58     USART_ITConfig(MODBUS_USART, USART_IT_TC, ENABLE);
 59   } else if(xTxEnable == FALSE) {
 60     MODBUS_RECIEVE();
 61     USART_ITConfig(MODBUS_USART, USART_IT_TC, DISABLE);
 62   }
 63 }
 64 
 65 BOOL
 66 xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
 67 {
 68   /*****************************引脚初始化*************************************/
 69   GPIO_InitTypeDef  GPIO_InitStructure;
 70   
 71   //时钟使能
 72   RCC_AHBPeriphClockCmd(MODBUS_USART_TX_CLK | MODBUS_USART_RX_CLK | MODBUS_USART_CTRL_CLK, ENABLE);
 73   MODBUS_USART_CLK_INIT(MODBUS_USART_CLK, ENABLE);
 74   
 75   //复用功能定义
 76   GPIO_PinAFConfig(MODBUS_USART_TX_PORT, MODBUS_USART_TX_SOURCE, MODBUS_USART_TX_AF);
 77   GPIO_PinAFConfig(MODBUS_USART_RX_PORT, MODBUS_USART_RX_SOURCE, MODBUS_USART_RX_AF);
 78   
 79   //引脚功能定义
 80   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
 81   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
 82   GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_DOWN;
 83   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_3; //50MHz
 84   
 85   //TX
 86   GPIO_InitStructure.GPIO_Pin = MODBUS_USART_TX_PIN;
 87   GPIO_Init(MODBUS_USART_TX_PORT, &GPIO_InitStructure);
 88   
 89   //RX
 90   GPIO_InitStructure.GPIO_Pin = MODBUS_USART_RX_PIN;
 91   GPIO_Init(MODBUS_USART_RX_PORT, &GPIO_InitStructure);
 92   
 93   //CTRL
 94   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_OUT;
 95   GPIO_InitStructure.GPIO_Pin   = MODBUS_USART_CTRL_PIN;
 96   GPIO_Init(MODBUS_USART_CTRL_PORT, &GPIO_InitStructure);
 97   MODBUS_RECIEVE(); //接收模式
 98   
 99   /*****************************串口初始化*************************************/
100   USART_InitTypeDef USART_InitStructure;
101   
102   USART_InitStructure.USART_BaudRate    = ulBaudRate;
103   USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
104   USART_InitStructure.USART_Mode        = USART_Mode_Rx|USART_Mode_Tx;
105   USART_InitStructure.USART_Parity      = USART_Parity_No;
106   USART_InitStructure.USART_StopBits    = USART_StopBits_1;
107   USART_InitStructure.USART_WordLength  = USART_WordLength_8b;
108   
109   USART_Init(MODBUS_USART, &USART_InitStructure);
110   USART_Cmd(MODBUS_USART, ENABLE);
111   vMBPortSerialEnable(FALSE, FALSE);
112   
113   /*****************************中断初始化*************************************/
114   NVIC_InitTypeDef  NVIC_InitStructure;
115   
116   NVIC_InitStructure.NVIC_IRQChannel          = USART3_4_IRQn;
117   NVIC_InitStructure.NVIC_IRQChannelCmd       = ENABLE;
118   NVIC_InitStructure.NVIC_IRQChannelPriority  = 1;
119   
120   NVIC_Init(&NVIC_InitStructure);
121   
122   return TRUE;
123 }
124 
125 BOOL
126 xMBPortSerialPutByte( CHAR ucByte )
127 {
128   /* Put a byte in the UARTs transmit buffer. This function is called
129    * by the protocol stack if pxMBFrameCBTransmitterEmpty( ) has been
130    * called. */
131   MODBUS_USART->TDR = ucByte; //此处不用等待发送完毕（TC），因为有发送完成中断
132   return TRUE;
133 }
134 
135 BOOL
136 xMBPortSerialGetByte( CHAR * pucByte )
137 {
138   /* Return the byte in the UARTs receive buffer. This function is called
139    * by the protocol stack after pxMBFrameCBByteReceived( ) has been called.
140    */
141   *pucByte = MODBUS_USART->RDR;
142   return TRUE;
143 }
144 
145 /* Create an interrupt handler for the transmit buffer empty interrupt
146  * (or an equivalent) for your target processor. This function should then
147  * call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that
148  * a new character can be sent. The protocol stack will then call 
149  * xMBPortSerialPutByte( ) to send the character.
150  */
151 static void prvvUARTTxReadyISR( void )
152 {
153     pxMBFrameCBTransmitterEmpty(  );
154 }
155 
156 /* Create an interrupt handler for the receive interrupt for your target
157  * processor. This function should then call pxMBFrameCBByteReceived( ). The
158  * protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
159  * character.
160  */
161 static void prvvUARTRxISR( void )
162 {
163     pxMBFrameCBByteReceived(  );
164 }
165 
166 void  prvvModbusUARTISR( void )
167 {
168   if(USART_GetITStatus(MODBUS_USART, USART_IT_TC) == SET) {
169     prvvUARTTxReadyISR();
170     USART_ClearITPendingBit(MODBUS_USART, USART_IT_TC);
171   }
172 
173   if(USART_GetITStatus(MODBUS_USART, USART_IT_RXNE) == SET) {
174     prvvUARTRxISR();
175     USART_ClearITPendingBit(MODBUS_USART, USART_IT_RXNE);
176   }
177 }

portserial.c