commc.c

c语言写的串口通讯程序,可以自己添加校验功能

#include <reg51.h>
#include <string.h>

#define INBUF_LEN 4   //数据长度

unsigned char inbuf1[INBUF_LEN];
unsigned char checksum,count3;
bit           read_flag=0;
unsigned char point=0;    //接收数据个数指示变量

void init_serialcomm(void)
{     SCON  = 0x50;       //SCON: serail mode 1, 8-bit UART, enable ucvr
    TMOD |= 0x20;       //TMOD: timer 1, mode 2, 8-bit reload
    PCON = 0x80;       //SMOD=1;
    TH1   = 0xCC;       //Baud:4800  fosc=11.0592MHz
    //TL1=   0xCC;        //T/C在方式2时，将16位计数器分成两个8位计数器，THi用来存放初值
                           // 当计数器溢出时，一方面将TFi置1申请中断，二另一方面自动将THi的值装入TLi.
    IE   |= 0x90;       //Enable Serial Interrupt
    TR1   = 1;          // timer 1 run
   // TI=1;
   PS=1;
}

//向串口发送一个字符
void send_char_com(unsigned char ch)
{

   SBUF=ch;
    while(TI==0);
    TI=0;
}

//向串口发送一个字符串，strlen为该字符串长度
void send_string_com(unsigned char *str,unsigned int strlen)
{     unsigned int k=0;
   point=0;
    do
    {
        send_char_com(*(str + k));
        k++;
    } while(k < strlen);
}

//串口接收中断函数
/*void serial () interrupt 4 using 3
{     if(RI)
    {
        unsigned char ch;
        RI = 0;

        ch=SBUF;
        if(ch>127)
        {
             count3=0;
             inbuf1[count3]=ch;
             checksum= ch-128;
        }
        else
        {
             count3++;
             inbuf1[count3]=ch;
             checksum ^= ch;
             if( (count3==(INBUF_LEN-1)) && (!checksum) )
             {
                 read_flag=1;  //如果串口接收的数据达到INBUF_LEN个，且校验没错，
                               //就置位取数标志
             }
        }
    }
}    */

void serial () interrupt 4 using 3      // 串口接收中断处理函数
{
    unsigned char ch;

    if(RI)
    {

        RI = 0;

      ch=SBUF;
       // if(ch=='s')
        //   read_flag=1;

      if(point==0)
            {
            if(ch==0x12)  //判断是否起始位
             point++;
            else
            point=0;
            }
    else if(point>0&&point<5)
          
         {
         inbuf1[0]=0x12;
         inbuf1[point++]=ch;
         
         }
     else point=0;
    if(TI)
    {TI=0;}
     }
 }

/*unsigned char C_checkdata(void)
 {
  unsigned char checkdata=0;
  for(point=0;point<4,TI=1;point++)
   {
    checkdata=checkdata|inbuf1[point];
   }       
  return(checkdata);
 }  */


main()
{

     unsigned char checkdata;

      init_serialcomm();  //初始化串口
    while(1)
    {
    
  //     checkdata=C_checkdata();
       if(point==4)
        
      //   if(checkdata==inbuf1[3])  
          {  read_flag=1;}
          if(read_flag)  //如果取数标志已置位，就将读到的数从串口发出
          {
               read_flag=0; //取数标志清0


            send_string_com(inbuf1,INBUF_LEN);
        
          }
    }

}