1、51单片机超声波测距程序/超声波测距,测距X围2cm-400cm;#include#include#define uint unsigned int#define uchar unsigned charsbit trig=P10;sbit echo=P32;sbit test=P11;/测试灯sbit dula=P26;sbit wela=P27;sbit BEEP=P23;uint timeh,timel,distance;uint ge,shi,bai,xiaoshu,flag,time;/*共阴极数码管不带小数点代码表*/uchar code list=0x3f , 0x06 , 0x5
2、b , 0x4f , 0x66 , 0x6d ,0x7d , 0x07 , 0x7f , 0x6f , 0x77 , 0x7c ,0x39 , 0x5e , 0x79 , 0x71 ;/*共阴极数码管带小数点代码表*/uchar code listtwo = 0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,0x87,0xff,0xef;/*长延时函数*/void delay(uint z)uint x,y;for(x=z;x0;x-)for(y=100;y0;y-);/*短延时函数*/void delay20us()uchar a;for(a=0;a100;a+);/*报
3、警函数*/void beer()/BEEP=0;delay(10);/*定时器初始化*/void initime0()TMOD=0x01;TH0=0;TL0=0;EA=0;ET0=0;EX0=0;/*外部中断函数*/void estern() interrupt 0timeh=TH0;timel=TL0;beer();flag=1;/进入中断,标志位就置1EX0=0;/同时关断外部中断和定时器 TR0=0;/*显示函数*/void display(distance)bai=distance/1000;shi=distance%1000/100;ge=distance%100;xiaoshu=d
4、istance%10;dula=1;P0=listxiaoshu;dula=0;P0=0xff;wela=1;P0=0xf7;wela=0;delay(2);dula=1;P0=listtwoge;dula=0;P0=0xff;wela=1;P0=0xfb;wela=0;delay(2);dula=1;P0=listshi;dula=0;P0=0xff;wela=1;P0=0xfd;wela=0;delay(1);dula=1;P0=listbai;dula=0;P0=0xff;wela=1;P0=0xfe;wela=0;delay(1);/*被调用子函数*/void diaoyong()ui
5、nt i;EA=0;echo=1;/为了检测电平的上下,首先必须拉高trig=1;delay20us();trig=0;while(echo=0);/如果进入中断 即接收到超声波就向下执行flag=0;/接收到就去除标志位EA=1;/同时打开总中断EX0=1;/打开外部中断TR0=1;/开定时器TH0=0;/定时器清零TL0=0;for(i=0;i100;i+)/等待测量的结果display(distance);/用100次显示循环来延时,解决数码管显示不亮问题/delay(50);/用延时函数数码管闪烁TR0=0;/延时一段时间后关断定时器EX0=0;/延时一段时间后关断外部中断if(flag=1)/如果进入中断,说明测距已经测好time=timeh*256+timel;/计算测定距离,并显示distance=time*0.1720;display(distance);if(flag=0)/如果没有进入中断,距离为0,同时灯闪烁distance=0;test=!test;/*主函数*/void main()initime0();test=0;trig=0;EA=1;while(1)diaoyong();display(distance);