8255A實現模擬交通燈的控制實驗 利用可編程並行接口芯片8255A，使用PB4—PB7與PC0—7

#define uchar unsigned char

#define uint unsigned int

uchar b=5,c;

unsigned char code a[]=;

sbit sg=P1^0;

sbit sy=P1^1;

sbit sr=P1^2;

sbit hg=P1^3;

sbit hy=P1^4;

sbit hr=P1^5;

sbit ge=P1^6;

sbit shi=P1^7;

uint num1,num2,num3;

void delay(unsigned int z1)

{

unsigned int a1,b1;

for(a1=z1;a1>0;a1--)

for(b1=12500;b1>0;b1--);

}

void main()

{

P2=0;

P1=0;

shi=1;

P2=a[8];

shi=0;

ge=1;

P2=a[4];

ge=0;

TMOD=0X11;

TH0=(65536-50000)/256;

TL0=(65536-50000)%256;

TH1=(65536-50000)/256;

TL1=(65536-50000)%256;

EA=1;

ET0=1;

ET1=1;

TR0=1;

TR1=1;

while(1)

{

switch(num2) //紅綠燈

{

case(0): //10s內s綠燈亮

sr=0;

hg=0;

sg=1;

hr=1;

break;

case(1): //5S：豎黃橫紅

sg=0;

sy=1;

delay(5);

sy=0;

delay(5);

break;

case(2): //10s：豎紅橫綠

sg=0;

sr=1;

sy=0;

hg=1;

hr=0;

break;

case(3): //5S：豎紅橫黃

hg=0;

hy=1;

delay(5);

hy=0;

delay(5);

break;

}

}

}

void timer0() interrupt 1 //定時器0

{

TH0=(65536-50000)/256;

TL0=(65536-50000)%256;

num1++;

if(num1==200)

num2=1;

if(num1==300)

num2=2;

if(num1==500)

num2=3;

if(num1==600)

{

num1=0;

num2=0;

}

}

void timer1() interrupt 3 //定時器1

{

TH1=(65536-50000)/256;

TL1=(65536-50000)%256;

num3++;

if(num3>=20) //數碼管顯示

{

num3=0;

c++;

ge=1;

P2=a[b++];

ge=0;

if(b>=10)

b=0;

if(b==1)

{

P2=a[9];

shi=1;

shi=0;

}

if(c>=15)

{

c=0;

shi=1;

P2=a[8];

shi=0;

ge=1;

P2=a[4];

ge=0;

b=5;

}

}

}