PIC16F877A 超声波测距1602显示距离

#include

#include

__CONFIG(0x1832);

#define uchar unsigned char

#define uint unsigned int

const uchar dis1[]={"The distance is"};

uchar dis2[5];

#define lcden RA0

#define rs RA1

unsigned long S;

uint time;

uchar i=0;

uchar S_buffer[4];

bit flag =0;

void delay(uint x)

{

uint a,b;

for(a=x;a>0;a--)

for(b=110;b>0;b--);

}

void write_com(uchar com)//写指令数据到LCD {

rs=0;

PORTB=com;

delay(5);

lcden=1;

delay(5);

lcden=0;

}

void write_data(uchar data)//写显示数据到LCD {

rs=1;

PORTB=data;

delay(5);

lcden=1;

delay(5);

lcden=0;

}

void lcd_init()

{

lcden=1;

write_com(0x38);

write_com(0x0c);

write_com(0x06);

write_com(0x01);

}

void shuju()//数据函数

{

dis2[0]=S/100+0x30;

dis2[1]=S/10%10+0x30;

dis2[2]=S%10+0x30;

dis2[3]='c';

dis2[4]='m';

}

void interrupt time0()

{

flag=0;

TMR1IF=0;

TMR1L=0;

TMR1H=0;

T1CON=0x20;

}

void init()

{

ADCON1=0X07;

OPTION=0X8f;

TRISA=0;

TRISB=0;

TRISC=0x04;

TRISD=0;

TRISE=0x04;

PORTB=0;

PORTC=0;

PORTD=0X01;

PORTE=0X07;

RBIE=0;

INTCON=0xc0;//PEIE使能和GIE（总中断）使能PIE1=0x01;//使能定时器1

TMR1L=0;

TMR1H=0;

}

void display()

{

shuju();

write_com(0x80+0x48);

for(i=0;i<5;i++)

{

write_data(dis2[i]);

}

}

void StartModule()

{

RC1=1; //启动一次模块

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

NOP();

RC1=0;

}

void Count(void)

{

time=TMR1H*256+TMR1L;

TMR1H=0;

TMR1L=0;

S=(int)(time*1.98)*1.3*3/10; //算出来是CM

/*if(((S<4)||(S>=400))||flag==0) //超出测量范围显示"999"

{

S=999;

}

else

{

S_buffer[i]=S; //将测量结果的数据放入缓冲区

i++;

if(i==4)

{

S=(S_buffer[0]+S_buffer[1]+S_buffer[2]+S_buffer[3])/4; //得到四个数据取平均

i=0;

} */

// }

}

void main()

{

uchar i;

init();

lcd_init();

i=0;

write_com(0x80);

while(dis1[i]!='\0')

{

write_data(dis1[i]);

i++;

}

while(1)

{

PORTA=0xff;

StartModule();

flag=1;

while((!RC2)&&flag); //当echo为零时等待,中断flag跳出等待

T1CON=0x21; //开启计数

while(RC2&&flag); //当echo为1计数并等待

T1CON=0x20; //关闭计数

Count(); //计算

display();

delay(50);

}

}