gps.c

GPS驱动集合

#include   <reg51.h>   
  #include   <string.h>   
    
  #define   INBUF_LEN   4       //   
    
  unsigned   char   inbuf1[INBUF_LEN];   
  unsigned   char   checksum,count3;   
  bit                       read_flag=0;   
    
  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       =   0xF4;               //Baud:1200     fosc=6.0MHz   
  IE       |=   0x90;               //Enable   Serial   Interrupt   
          TR1       =   1;                     //   timer   1   run   
        //   TI=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;   
  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   
    }   
  }   
  }   
  }   
    
    
  main()   
  {   
  init_serialcomm();     //初始化串口   
  while(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);   
                      }   
  }   
    
  }