52单片机超声波测距并用lcd1602显示

这个项目需要使用52单片机和超声波传感器来测量距离，并将结果显示在LCD1602上。以下是详细步骤：

1. 连接硬件：将超声波传感器的Trig引脚连接到P1.0口，Echo引脚连接到P1.1口，LCD1602的RS、RW、E分别连接到P2.0、P2.1、P2.2口，D4-D7四个引脚分别连接到P2.4-P2.7口。

2. 初始化LCD1602：在主函数中调用LCD1602_Init()函数，初始化LCD1602。

3. 初始化定时器：使用定时器来控制超声波的发射和接收时间，需要在主函数中调用Timer0_Init()函数，初始化定时器。

4. 测距并显示结果：在主函数中调用MeasureDistance()函数，测量距离并将结果显示在LCD1602上。

下面是代码示例：

#include <reg52.h>
#include <intrins.h>

#define uint unsigned int
#define uchar unsigned char

sbit TRIG = P1^0;
sbit ECHO = P1^1;

sbit RS = P2^0;
sbit RW = P2^1;
sbit E = P2^2;
sbit LCD_D4 = P2^4;
sbit LCD_D5 = P2^5;
sbit LCD_D6 = P2^6;
sbit LCD_D7 = P2^7;

void delay_us(uint us)
{
    while(us--)
        _nop_();
}

void delay_ms(uint ms)
{
    uchar i, j;
    while(ms--)
        for(i=0; i<250; i++)
            for(j=0; j<255; j++);
}

void LCD1602_WriteCmd(uchar cmd)
{
    RS = 0;
    RW = 0;
    LCD_D7 = cmd >> 7;
    LCD_D6 = (cmd >> 6) & 0x01;
    LCD_D5 = (cmd >> 5) & 0x01;
    LCD_D4 = (cmd >> 4) & 0x01;
    E = 1;
    _nop_();
    E = 0;
    LCD_D7 = (cmd >> 3) & 0x01;
    LCD_D6 = (cmd >> 2) & 0x01;
    LCD_D5 = (cmd >> 1) & 0x01;
    LCD_D4 = cmd & 0x01;
    E = 1;
    _nop_();
    E = 0;
    delay_us(50);
}

void LCD1602_WriteData(uchar dat)
{
    RS = 1;
    RW = 0;
    LCD_D7 = dat >> 7;
    LCD_D6 = (dat >> 6) & 0x01;
    LCD_D5 = (dat >> 5) & 0x01;
    LCD_D4 = (dat >> 4) & 0x01;
    E = 1;
    _nop_();
    E = 0;
    LCD_D7 = (dat >> 3) & 0x01;
    LCD_D6 = (dat >> 2) & 0x01;
    LCD_D5 = (dat >> 1) & 0x01;
    LCD_D4 = dat & 0x01;
    E = 1;
    _nop_();
    E = 0;
    delay_us(50);
}

void LCD1602_Init()
{
    delay_ms(15);
    LCD1602_WriteCmd(0x38);
    delay_ms(5);
    LCD1602_WriteCmd(0x38);
    delay_ms(5);
    LCD1602_WriteCmd(0x38);
    delay_ms(5);
    LCD1602_WriteCmd(0x08);
    delay_ms(5);
    LCD1602_WriteCmd(0x01);
    delay_ms(5);
    LCD1602_WriteCmd(0x06);
    delay_ms(5);
    LCD1602_WriteCmd(0x0c);
    delay_ms(5);
}

void Timer0_Init()
{
    TMOD |= 0x01;
    TH0 = 0;
    TL0 = 0;
    ET0 = 1;
    TR0 = 1;
}

void MeasureDistance()
{
    uchar distance;
    uint time;
    TRIG = 0;
    delay_us(2);
    TRIG = 1;
    delay_us(10);
    TRIG = 0;
    while(!ECHO);
    TH0 = 0;
    TL0 = 0;
    while(ECHO);
    time = TH0 * 256 + TL0;
    distance = time / 58;
    LCD1602_WriteCmd(0x80);
    LCD1602_WriteData('D');
    LCD1602_WriteData('i');
    LCD1602_WriteData('s');
    LCD1602_WriteData('t');
    LCD1602_WriteData('a');
    LCD1602_WriteData('n');
    LCD1602_WriteData('c');
    LCD1602_WriteData('e');
    LCD1602_WriteCmd(0x8f);
    LCD1602_WriteData(distance / 100 + '0');
    LCD1602_WriteData(distance % 100 / 10 + '0');
    LCD1602_WriteData(distance % 10 + '0');
    LCD1602_WriteData('c');
    LCD1602_WriteData('m');
}

void main()
{
    LCD1602_Init();
    Timer0_Init();
    while(1)
    {
        MeasureDistance();
        delay_ms(500);
    }
}

void Timer0_ISR() interrupt 1
{
    TH0 = 0;
    TL0 = 0;
}

其中，delay_us()和delay_ms()函数用来延时，LCD1602_WriteCmd()和LCD1602_WriteData()函数用来向LCD1602写入指令和数据，LCD1602_Init()函数用来初始化LCD1602，Timer0_Init()函数用来初始化定时器，MeasureDistance()函数用来测量距离并显示结果。在主函数中，先调用LCD1602_Init()和Timer0_Init()函数进行初始化，然后进入循环，不停地调用MeasureDistance()函数测量距离并显示结果，每次测量完毕后延时500ms，以免频繁测量导致干扰。最后，定时器中断服务程序Timer0_ISR()用来清零定时器计数器。