基于单片机的数字测速仪设计 - 图文(9)

附录

1、系统原理图及PCB

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2、程序代码 #include #include\

//==============主函数================ void main() { }

time0_int0_init();//定时器0和外部中断0的初始化 while(!TR0) //上电一直未切割时就显示 0.0.0.0 { init_display(); }

while(1) { }

if(!change)//按下切换按键显示里程 { }

delay1m(5); if(!change) { flag = ~flag; }

while(!change);

//===============定时器0中断函数================ void time0_interrupt()interrupt 1

{

TL0 = (65536 - 5000) % 256;// 12M晶振，5ms定时 TH0 = (65536 - 5000) / 256; display_function(); time_counter++; time_counter8++;

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{ }

if(time_counter8 >= 1600)//大于8s没切割，车子视为停下了,速度

为：0，但里程还记着

}

time_counter8 = 0; speed = 0;//速度为 0

point1 = 0;

buf1[3] = speed;buf1[2] = speed/10;

buf1[1] = speed/100;buf1[0] = speed/1000;

//===================外部中断0中断函数====================== void int0_interrupt()interrupt 0 { external_counter++; {

if(external_counter ==1 )TR0 = ~TR0;//第一次切割打开定时器0 if(external_counter == 65535)external_counter = 0; time_counter8 = 0; //只要8秒内有切割，车子就任在运行

if(external_counter % 2 == 0)//切割2次 更新下速度

//*5是因为

中断一次是5MS

if(flag1==0){speed =((ulong)(36000)*zhouchang)/(time_counter * 5);flag1=1;} else if(flag1==1){speed =((ulong)(36000)*2*zhouchang)/(time_counter * 5);}//速度：单位为 m/h ,*1000的目的是不出现浮点数 数

if((speed >= 100)&&(speed < 1000)) //100 ---- 1000 3位整{ point1 = 1;buf1[3] = speed;buf1[2] = speed/10; buf1[1] = speed/100;buf1[0] = 0;}

else if((speed >= 1000)&&(speed < 10000)) //1000 ---- 10000

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4位整数

} {

s = (ulong)external_counter * zhouchang; //里程：单位为 cm if((s >= 1000)&&(s < 10000)) { point2 = 1; // 0.012 001212 buf2[3] = s/100;buf2[2] = s/1000;

buf2[1] = 0;buf2[0] = 0;}// 4位整数

else if((s >= 10000)&&(s < 100000)) { point2 = 1; buf2[3] = s/100;buf2[2] = s/1000;

buf2[1] = s/10000;buf2[0] = 0;}// 5位整数

{ point1 = 1;speed = (uint)speed; buf1[3] = speed;buf1[2] = speed/10; buf1[1] = speed/100;buf1[0] = speed/1000;} else if((speed >= 10000)&&(speed < 100000)) //10000 ----{ point1 = 2; buf1[3] = speed/10;buf1[2] = speed/100; buf1[1] = speed/1000;buf1[0] = speed/10000;} else if((speed >= 100000)&&(speed < 1000000)) //100000 ------ { point1 = 3; buf1[3] = speed/100;buf1[2] = speed/1000; buf1[1] = speed/10000;buf1[0] = speed/100000;} time_counter = 0;

- 100000 5位整数

1000000 6位整数

if(external_counter % 8 == 0)//每切割8次 更新下里程

0.123 012345

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