串口实现modbus通讯

代码

#include "sys.h"
#include "485.h"    
#include "delay.h"
#include "modbus.h"
void RS485_Init(u32 bound){
  //GPIO端口设置
     GPIO_InitTypeDef GPIO_InitStructure;
     USART_InitTypeDef USART_InitStructure;
     NVIC_InitTypeDef NVIC_InitStructure;
         
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD|RCC_APB2Periph_GPIOA , ENABLE);    //使能GPIO时钟
//         RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD | RCC_APB2Periph_AFIO, ENABLE);    //使能GPIO时钟
     RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);    //使能USART2时钟
//     GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE);//调用重映射函数 
        
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;                 //LED0-->PA.8 端口配置
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;          //推挽输出
     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;         //IO口速度为50MHz
     GPIO_Init(GPIOD, &GPIO_InitStructure);                     
     GPIO_SetBits(GPIOD,GPIO_Pin_3);    
        
    
//    //USART1_TX   GPIO
//  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //P
//  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
//  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //复用推挽输出
//  GPIO_Init(GPIOD, &GPIO_InitStructure);//初始化GPIO
//   
//  //USART1_RX      GPIOA初始化
//  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;//PA
//  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
//  GPIO_Init(GPIOD, &GPIO_InitStructure);//初始化GPIO 
  

     //USART2_TX   PA.2
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; 
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //复用推挽输出
    GPIO_Init(GPIOA, &GPIO_InitStructure); 
   
    //USART2_RX      PA.3
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
    GPIO_Init(GPIOA, &GPIO_InitStructure);  

  //Usart1 NVIC 配置
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0 ;//抢占优先级0
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;        //子优先级0
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;            //IRQ通道使能
    NVIC_Init(&NVIC_InitStructure);    //根据指定的参数初始化VIC寄存器
  
   //USART 初始化设置

    USART_InitStructure.USART_BaudRate = bound;//串口波特率
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式
    USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个停止位
    USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;    //收发模式

  USART_Init(USART2, &USART_InitStructure); //初始化串口1
  USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//开启串口接受中断
  USART_Cmd(USART2, ENABLE);                    //使能串口1 
  RS485_TX_EN=0;            //默认为接收模式
}
/***********************************************/


u8 RS485_8bit_PutChar_send(u8 ch)
 {
    RS485_TX_EN=1;
    USART_SendData(USART2, (u8) ch);
    while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET)
   {
   }
     RS485_TX_EN=0;
   return ch;
}
void RS485_8bit_PutString_send(u8* buf , u16 len)
{   u8 i;
//    RS485_TX_EN=1;
    for(i=0;i<len;i++)
    {
        RS485_8bit_PutChar_send(*buf++);
    }
    //    RS485_TX_EN=0;
}

u16 RS485_16bit_PutChar_send(u16 ch)
{
    /* Write a character to the USART */
    USART_SendData(USART2, (u8) ch);
    while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET)
   {
   }
   return ch;
}
void RS485_16bit_PutString_send(u16* buf , u16 len)
{   u8 i;
    for(i=0;i<len;i++)
    {
        RS485_16bit_PutChar_send(*buf++);
    }
}

void RS485_byte(u8 d)  //485发送一个字节
{
  
 // RS485_RT_1;  //??
  USART_SendData(USART2, d);
      while(USART_GetFlagStatus(USART2,USART_FLAG_TC)==RESET);
  USART_ClearFlag(USART2,USART_FLAG_TC );
   
 // RS485_RT_0;  //?
  
}

void USART2_IRQHandler(void)                    //串口1中断服务程序
    { u8 st,sbuf;
         if (USART_GetFlagStatus(USART2, USART_FLAG_ORE) != RESET)//注意！不能使用if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)来判断  
    {  
        sbuf=USART_ReceiveData(USART2);  
    } 
    st=USART_GetITStatus(USART2, USART_IT_RXNE);
    if(st==SET)  //
   {            
          sbuf=USART2->DR;
     if( modbus.reflag==1)  //有数据包正在处理
         {
           return ;
         }             
          modbus.rcbuf[modbus.recount++]=sbuf;
      modbus.timout=0;  
      if(modbus.recount==1)  //收到主机发来的一帧数据的第一字节
            {
              modbus.timrun=1;  //启动定时
            }
            USART_ClearITPendingBit(USART2,USART_IT_RXNE);
   } 

  }