我的程序和modbusslave连接 只有接收没有发送 听说要加一个CRC校验码 但是我不知道加在哪里 求大神帮助

小菜鸟ning

#include "stm32f10x.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_tim.h"
#include "stm32f10x_usart.h"
#include "delay.h"
u8 counter;
void UART2Write(u8* data,int len);
void UART2_SendByte(u16 Data);
void USART_config(u32 bound)
{
 GPIO_InitTypeDef GPIO_InitStructure; 
 USART_InitTypeDef USART_InitStructure;
 NVIC_InitTypeDef NVIC_InitStructure;
//RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2|RCC_APB2Periph_GPIOA,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO,ENABLE); //这里一定要配置复用 AFIO
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2 ,ENABLE);
USART_DeInit(USART2);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AF_PP;    
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode =GPIO_Mode_IN_FLOATING;    
GPIO_Init(GPIOA, &GPIO_InitStructure);
USART_InitStructure.USART_BaudRate = bound;
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;  //为硬盘数据流控制
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //接收发送模式
NVIC_InitStructure.NVIC_IRQChannel  = USART2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3; 
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
USART_Init(USART2, &USART_InitStructure);
USART_Cmd(USART2, ENABLE); 
}
void Timer_Config(void)
{
 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);//Timer3_Clock=APB1*2;
    TIM_DeInit(TIM3);                          //复位定时器
    TIM_TimeBaseStructure.TIM_Period=4999;        //定时器初始值
    TIM_TimeBaseStructure.TIM_Prescaler=(7200-1);        //时钟预分频
    TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;   // 时钟分割
    TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
    TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);      //初始化定时器的值
    TIM_ClearFlag(TIM3,TIM_FLAG_Update);                //清除定时器中断标志 
    TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE);        //使能中断
    TIM_Cmd(TIM3,ENABLE);                        //开启时钟
}
void NVIC_Config(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
void TIM3_IRQHandler(void)//定时器中断函数
{

if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) // 跟下面一句连在一起用的 判断是否中断有触发，出发后就清除
{   
TIM_ClearITPendingBit(TIM3, TIM_IT_Update); //清除中断标志
counter++;

}
}
/*串口中断函数  什么时候用的到的呢 就是说main函数里面一直在执行自己的东西 然后突然有东西给单片机啦 下面判断if（）发送寄存器空 被触发  就暂停工作 执行中断函数*/
void USART2_IRQHandler(void)
{
u8 RX_dat;  
if(USART_GetITStatus(USART2,USART_IT_RXNE)!=RESET)  //判断发生接收中断
  {
RX_dat = USART_ReceiveData(USART2);  
while(USART_GetFlagStatus(USART2, USART_FLAG_TC) == RESET)
{
}
USART_SendData(USART2,  RX_dat);
  }
}
int main(void)
{    
  u8 recvBuff[256]={0};
int len = 0;
Timer_Config();
NVIC_Config();
SystemInit();
USART_config(9600);
delay_init(72);
while(1)
{
if(counter==4)
{
recvBuff[0] = 0x01; 
recvBuff[1] = 0x03;
   recvBuff[2] = 0x00;
recvBuff[3] = 0x02;
recvBuff[4] = 0x00;
recvBuff[5] = 0x08;
recvBuff[6] = 0XE5;
recvBuff[7] = 0XC9;
len =8;
      UART2Write(recvBuff,len);
 counter =0;
     }  
}
}

/* 下面是一个发送数组的函数 首先先传递 第二个函数 是一个字节一个字节的发送*/
void UART2Write(u8* data,int len)  
{
   u8 i;
   for(i =0;i<8;i++)
{
UART2_SendByte(data);
   }
}
 void UART2_SendByte(u16 Data)
{ 
   while (!(USART2->SR & USART_FLAG_TXE)); //usart2->SR是串口状态寄存器 USART_FLAG_TXE传输数据寄存器空标记   
   USART_SendData(USART2, Data); 
}

chy712

const unsigned char auchCRCHi[ ] = {
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,
0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,
0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,
0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,
0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,
0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,
0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,
0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,
0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,
0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,
0x80,0x41,0x00,0xC1,0x81,0x40};

const unsigned char auchCRCLo[ ]={
0x00,0xC0,0xC1,0x01,0xC3,0x03,0x02,0xC2,0xC6,0x06,
0x07,0xC7,0x05,0xC5,0xC4,0x04,0xCC,0x0C,0x0D,0xCD,
0x0F,0xCF,0xCE,0x0E,0x0A,0xCA,0xCB,0x0B,0xC9,0x09,
0x08,0xC8,0xD8,0x18,0x19,0xD9,0x1B,0xDB,0xDA,0x1A,
0x1E,0xDE,0xDF,0x1F,0xDD,0x1D,0x1C,0xDC,0x14,0xD4,
0xD5,0x15,0xD7,0x17,0x16,0xD6,0xD2,0x12,0x13,0xD3,
0x11,0xD1,0xD0,0x10,0xF0,0x30,0x31,0xF1,0x33,0xF3,
0xF2,0x32,0x36,0xF6,0xF7,0x37,0xF5,0x35,0x34,0xF4,
0x3C,0xFC,0xFD,0x3D,0xFF,0x3F,0x3E,0xFE,0xFA,0x3A,
0x3B,0xFB,0x39,0xF9,0xF8,0x38,0x28,0xE8,0xE9,0x29,
0xEB,0x2B,0x2A,0xEA,0xEE,0x2E,0x2F,0xEF,0x2D,0xED,
0xEC,0x2C,0xE4,0x24,0x25,0xE5,0x27,0xE7,0xE6,0x26,
0x22,0xE2,0xE3,0x23,0xE1,0x21,0x20,0xE0,0xA0,0x60,
0x61,0xA1,0x63,0xA3,0xA2,0x62,0x66,0xA6,0xA7,0x67,
0xA5,0x65,0x64,0xA4,0x6C,0xAC,0xAD,0x6D,0xAF,0x6F,
0x6E,0xAE,0xAA,0x6A,0x6B,0xAB,0x69,0xA9,0xA8,0x68,
0x78,0xB8,0xB9,0x79,0xBB,0x7B,0x7A,0xBA,0xBE,0x7E,
0x7F,0xBF,0x7D,0xBD,0xBC,0x7C,0xB4,0x74,0x75,0xB5,
0x77,0xB7,0xB6,0x76,0x72,0xB2,0xB3,0x73,0xB1,0x71,
0x70,0xB0,0x50,0x90,0x91,0x51,0x93,0x53,0x52,0x92,
0x96,0x56,0x57,0x97,0x55,0x95,0x94,0x54,0x9C,0x5C,
0x5D,0x9D,0x5F,0x9F,0x9E,0x5E,0x5A,0x9A,0x9B,0x5B,
0x99,0x59,0x58,0x98,0x88,0x48,0x49,0x89,0x4B,0x8B,
0x8A,0x4A,0x4E,0x8E,0x8F,0x4F,0x8D,0x4D,0x4C,0x8C,
0x44,0x84,0x85,0x45,0x87,0x47,0x46,0x86,0x82,0x42,
0x43,0x83,0x41,0x81,0x80,0x40};

//CRC计算的函数，在网上都能找到，多的很
u16 CRC16(u8 puchMsg[],u16 usDataLen)
{
u8 uchCRCHi=0xff;
u8 uchCRCLo=0xff; 
u16 uIndex;
u16 i,result;
for(i=0;i<usDataLen;i++)
{
uIndex=uchCRCHi^(puchMsg);
uchCRCHi=uchCRCLo^auchCRCHi[uIndex];
uchCRCLo=auchCRCLo[uIndex];
}
result=uchCRCHi<<8|uchCRCLo;
return result;
}


然后你就用CRC16得到前6个字节算出来的CRC值填充到最后两个字节就可以了
crc=CRC16(recvBuff,6);
recvBuff[6]=(u8)(crc>>8);
recvBuff[7]=(u8)crc;

dozm

额。。。。。

正点原子

帮顶。。。。