query.c

主要是有关单片机串口通讯的相关程序

#include <reg51.h>
#define uchar unsigned    char
#define uint unsigned    int

#define INBUF_LEN 4

uchar inbuf[INBUF_LEN];
uchar checksum,count3;
bit   read_flag=0;

void InitComm(void)
{
    SCON  = 0x50;       //SCON: serail mode 1, 8-bit UART, enable ucvr
    TMOD |= 0x20;       //TMOD: timer 1, mode 2, 8-bit reload
    PCON |= 0x00;       //SMOD=1;
    TH1   = 0xF4;       //Baud:2400  fosc=11.0592MHz
    TL1   = 0xF4;       //Baud:2400  fosc=11.0592MHz
//    IE   |= 0x90;       //Enable Serial Interrupt
    TR1   = 1;          // timer 1 run
}

void SendChar(uchar ch)
{
    SBUF=ch;
    while(TI==0);
    TI=0;
}

void SendString(uchar *str,uint strlen)
{
    unsigned int k;

    checksum = 0;
    for (k=0;k<strlen;k++)
    {
        checksum ^= *(str+k);
    }
    checksum |= 0x80;
    SendChar(checksum);
    k = 0;
    do
    {
        SendChar(*(str + k));
        k++;
    } while(k < strlen);
}

void serial () interrupt 4 using 1
{
    uchar ch;
    if(RI)
    {
        RI = 0;
        ch=SBUF;
        if(ch>127)
        {
             count3=0;
             checksum= ch&0x7F;
        }
        else
        {
             inbuf[count3++]=ch;
             checksum ^= ch;
             if( (count3==INBUF_LEN) && ((checksum&0x7F)==0) )
             {
                 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
             }
             if(count3>=INBUF_LEN) count3 = 0;
        }
    }
}

uint BIN2BCD(int bin)
{
    uint a, v;
    a = bin%10;
    v = a;
    bin /= 10;
    a = bin%10;
    v |= a<<4;
    bin /= 10;
    a = bin%10;
    v |= a<<8;
    bin /= 10;
    a = bin%10;
    v |= a<<12;
    return(v);
}

sbit SRC = P1^0;
sbit SRC1 = P1^1;
sbit SRC2 = P1^2;
sbit SRC3 = P1^3;
sbit QUE = P1^7;

int kbhit()
{
    unsigned char i;
    SRC = 0;
    SRC1 = 0;
    SRC2 = 0;
    SRC3 = 0;
    i =QUE;
    if(i==0)
    {
       return(1);
    }
    return(0);
}

void Unpack(uint spd,uchar *buf)
{
   buf[0] = ((spd&0xF000)>>12) | 0x30;
   buf[1] = ((spd&0x0F00)>>8) | 0x30;
   buf[2] = ((spd&0x00F0)>>4) | 0x30;
   buf[3] = (spd&0x000F) | 0x30;
}

uint Speed = 1000;

void Delay(int t)
{
  int  i,j;
    for(i=0;i<t;i++)
    { for(j=0;j<2;j++); }
}

void main()
{
  unsigned int spd; uchar ch;

  InitComm();
  inbuf[0] = '8';
  inbuf[1] = '7';
  inbuf[2] = '6';
  inbuf[3] = '5';
  ch = 0x8C;
  SendString(inbuf,INBUF_LEN);

  while(1);
//  while(1)
 // {
      Delay(30000);
//    if(kbhit())
//    {
        Speed++;
        spd = BIN2BCD(Speed);
        Unpack(spd, inbuf);
        SendString(inbuf,INBUF_LEN);
//    }
 // }
  while(1);
}