7．C語言源程序

#include AT89X51.H>

unsigned char ID;

void delay10ms(void)

{

unsigned char i,j;

for(i=20;i>0;i--)

for(j=248;j>0;j--);

}

void delay02s(void)

{

unsigned char i;

for(i=20;i>0;i--)

{delay10ms();

}

}

void main(void)

{ while(1)

{ if(P3_7==0)

{delay10ms();

if(P3_7==0)

{

ID++;

if(ID==4)

{

ID=0;

}

while(P3_7==0);

}

}

switch(ID)

{ case 0:

P1_0=~P1_0;

delay02s();

break;

case 1:

P1_1=~P1_1;

delay02s();

break;

case 2:

P1_2=~P1_2;

delay02s();

break;

case 3:

P1_3=~P1_3;

delay02s();

break;

}

}