51单片机超声波测距l用cd1602显示程序

以下是一个简单的51单片机超声波测距并用CD1602液晶显示的程序：

#include<reg52.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int

sbit RS=P2^0;   //定义1602端口
sbit RW=P2^1;
sbit EN=P2^2;
sbit Trig=P1^0; //定义超声波端口
sbit Echo=P1^1;

uchar dat[4];    //定义显示数据数组

void InitLcd();   //函数声明
void WriteCommand(uchar com);
void WriteData(uchar date);
void WriteString(uchar *s);
void DelayMS(uint ms);
void DelayUS(uint us);
void SendPulse();
uint MeasureDistance();

void main() 
{
    uint distance;
    InitLcd();
    WriteString("Distance:");
    while(1)
    {
        distance = MeasureDistance();
        dat[3] = distance%10+'0';    //个位数字
        dat[2] = distance/10%10+'0'; //十位数字
        dat[1] = distance/100%10+'0';//百位数字
        dat[0] = distance/1000+'0';  //千位数字
        WriteCommand(0x80+0x40+0);   //液晶第二行第一列开始
        WriteData(dat[0]);
        WriteData(dat[1]);
        WriteData(dat[2]);
        WriteData(dat[3]);
        WriteString(" cm");
        DelayMS(50);
    }
}

void InitLcd()  //初始化液晶
{
    WriteCommand(0x38);
    WriteCommand(0x0c);
    WriteCommand(0x06);
    WriteCommand(0x01);
}

void WriteCommand(uchar com)   //写入命令
{
    RS = 0;
    RW = 0;
    P0 = com;
    EN = 1;
    DelayMS(5);
    EN = 0;
}

void WriteData(uchar date)     //写入数据
{
    RS = 1;
    RW = 0;
    P0 = date;
    EN = 1;
    DelayMS(5);
    EN = 0;
}

void WriteString(uchar *s)     //写入字符串
{
    while(*s)
    {
        WriteData(*s++);
    }
}

void DelayMS(uint ms)          //延时函数
{
    uchar i, j;
    for(i=ms; i>0; i--)
    {
        for(j=110; j>0; j--);
    }
}

void DelayUS(uint us)          //微秒延时函数
{
    while(us--);
}

void SendPulse()               //发送超声波脉冲
{
    Trig = 1;
    DelayUS(10);
    Trig = 0;
}

uint MeasureDistance()         //测量距离
{
    uint distance;
    SendPulse();
    while(Echo == 0);
    TH1 = 0;
    TL1 = 0;
    TR1 = 1;
    while(Echo == 1);
    TR1 = 0;
    distance = (TH1<<8 | TL1)/58;
    return distance;
}

该程序使用了定时器1来测量超声波回响时间，然后计算距离并将其显示在CD1602液晶上。程序中还包括了常用的LCD1602初始化、写入命令、写入数据、写入字符串等函数。