用4×4组成0－9数字键及确认键。
    用8位数码管组成显示电路提示信息，当输入密码时，只显示“8.”，当密码位数输入完毕按下确认键时，对输入的密码与设定的密码进行比较，若密码正确，则门开，此处用LED发光二极管亮一秒钟做为提示，同时发出“叮咚”声；若密码不正确，禁止按键输入3秒，同时发出“嘀、嘀”报警声；若在3秒之内仍有按键按下，则禁止按键输入3秒被重新禁止。

#include <AT89X52.H>

 

unsigned char ps[]={1,2,3,4,5};

 

unsigned char code dispbit[]={0xfe,0xfd,0xfb,0xf7,

0xef,0xdf,0xbf,0x7f};

unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66,

0x6d,0x7d,0x07,0x7f,0x6f,

0x77,0x7c,0x39,0x5e,0x79,0x71,

0x00,0x40,0x73,0xff};

unsigned char dispbuf[8]={18,16,16,16,16,16,16,16};

unsigned char dispcount;

unsigned char flashcount;

unsigned char temp;

unsigned char key;

unsigned char keycount;

unsigned char pslen=5;

unsigned char getps[6];

bit keyoverflag;

bit errorflag;

bit rightflag;

unsigned int second3;

unsigned int aa,bb;

unsigned int cc;

bit okflag;

bit alarmflag;

bit hibitflag;

unsigned char oka,okb;

 

 

void main(void)

{

unsigned char i,j;

 

TMOD=0x01;

TH0=(65536-500)/256;

TL0=(65536-500)%256;

TR0=1;

ET0=1;

EA=1;

 

while(1)

{

P3=0xff;

P3_4=0;

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

for(i=10;i>0;i--)

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

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

switch(temp)

{

case 0x0e:

key=7;

break;

case 0x0d:

key=8;

break;

case 0x0b:

key=9;

break;

case 0x07:

key=10;

break;

}

temp=P3;

P1_1=~P1_1;

if((key>=0) && (key<10))

{

if(keycount<6)

{

getps[keycount]=key;

dispbuf[keycount+2]=19;

}

keycount++;

if(keycount==6)

{

keycount=6;

 

}

else if(keycount>6)

{

keycount=6;

keyoverflag=1;//key overflow

}

}

else if(key==12)//delete key

{

if(keycount>0)

{

keycount--;

getps[keycount]=0;

dispbuf[keycount+2]=16;

}

else

{

keyoverflag=1;

}

}

else if(key==15)//enter key

{

if(keycount!=pslen)

{

errorflag=1;

rightflag=0;

second3=0;

}

else

{

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

{

if(getps[i]!=ps[i])

{

i=keycount;

errorflag=1;

rightflag=0;

second3=0;

goto a;

}

}

errorflag=0;

rightflag=1;

a:i=keycount;

}

}

temp=temp & 0x0f;

while(temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

}

keyoverflag=0;//?????????

}

}

 

P3=0xff;

P3_5=0;

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

for(i=10;i>0;i--)

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

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

switch(temp)

{

case 0x0e:

key=4;

break;

case 0x0d:

key=5;

break;

case 0x0b:

key=6;

break;

case 0x07:

key=11;

break;

}

temp=P3;

P1_1=~P1_1;

if((key>=0) && (key<10))

{

if(keycount<6)

{

getps[keycount]=key;

dispbuf[keycount+2]=19;

}

keycount++;

if(keycount==6)

{

keycount=6;

}

else if(keycount>6)

{

keycount=6;

keyoverflag=1;//key overflow

}

}

else if(key==12)//delete key

{

if(keycount>0)

{

keycount--;

getps[keycount]=0;

dispbuf[keycount+2]=16;

}

else

{

keyoverflag=1;

}

}

else if(key==15)//enter key

{

if(keycount!=pslen)

{

errorflag=1;

rightflag=0;

second3=0;

}

else

{

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

{

if(getps[i]!=ps[i])

{

i=keycount;

errorflag=1;

rightflag=0;

second3=0;

goto a4;

}

}

errorflag=0;

rightflag=1;

a4:i=keycount;

}

}

temp=temp & 0x0f;

while(temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

}

keyoverflag=0;//?????????

}

}

 

P3=0xff;

P3_6=0;

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

for(i=10;i>0;i--)

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

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

switch(temp)

{

case 0x0e:

key=1;

break;

case 0x0d:

key=2;

break;

case 0x0b:

key=3;

break;

case 0x07:

key=12;

break;

}

temp=P3;

P1_1=~P1_1;

if((key>=0) && (key<10))

{

if(keycount<6)

{

getps[keycount]=key;

dispbuf[keycount+2]=19;

}

keycount++;

if(keycount==6)

{

keycount=6;

}

else if(keycount>6)

{

keycount=6;

keyoverflag=1;//key overflow

}

}

else if(key==12)//delete key

{

if(keycount>0)

{

keycount--;

getps[keycount]=0;

dispbuf[keycount+2]=16;

}

else

{

keyoverflag=1;

}

}

else if(key==15)//enter key

{

if(keycount!=pslen)

{

errorflag=1;

rightflag=0;

second3=0;

}

else

{

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

{

if(getps[i]!=ps[i])

{

i=keycount;

errorflag=1;

rightflag=0;

second3=0;

goto a3;

}

}

errorflag=0;

rightflag=1;

a3:i=keycount;

}

}

temp=temp & 0x0f;

while(temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

}

keyoverflag=0;//?????????

}

}

 

P3=0xff;

P3_7=0;

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

for(i=10;i>0;i--)

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

temp=P3;

temp=temp & 0x0f;

if (temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

switch(temp)

{

case 0x0e:

key=0;

break;

case 0x0d:

key=13;

break;

case 0x0b:

key=14;

break;

case 0x07:

key=15;

break;

}

temp=P3;

P1_1=~P1_1;

if((key>=0) && (key<10))

{

if(keycount<6)

{

getps[keycount]=key;

dispbuf[keycount+2]=19;

}

keycount++;

if(keycount==6)

{

keycount=6;

}

else if(keycount>6)

{

keycount=6;

keyoverflag=1;//key overflow

}

}

else if(key==12)//delete key

{

if(keycount>0)

{

keycount--;

getps[keycount]=0;

dispbuf[keycount+2]=16;

}

else

{

keyoverflag=1;

}

}

else if(key==15)//enter key

{

if(keycount!=pslen)

{

errorflag=1;

rightflag=0;

second3=0;

}

else

{

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

{

if(getps[i]!=ps[i])

{

i=keycount;

errorflag=1;

rightflag=0;

second3=0;

goto a2;

}

}

errorflag=0;

rightflag=1;

a2:i=keycount;

}

}

temp=temp & 0x0f;

while(temp!=0x0f)

{

temp=P3;

temp=temp & 0x0f;

}

keyoverflag=0;//?????????

}

}

}

}

void t0(void) interrupt 1 using 0

{

TH0=(65536-500)/256;

TL0=(65536-500)%256;

flashcount++;

if(flashcount==8)

{

flashcount=0;

P0=dispcode[dispbuf[dispcount]];

P2=dispbit[dispcount];

dispcount++;

if(dispcount==8)

{

dispcount=0;

}

}

 

if((errorflag==1) && (rightflag==0))

{

bb++;

if(bb==800)

{

bb=0;

alarmflag=~alarmflag;

}

if(alarmflag==1)//sound alarm signal

{

P1_7=~P1_7;

}

 

aa++;

if(aa==800)//light alarm signal

{

aa=0;

P1_0=~P1_0;

}

second3++;

if(second3==6400)

{

second3=0;

errorflag=0;

rightflag=0;

alarmflag=0;

bb=0;

aa=0;

}

}

else if((errorflag==0) && (rightflag==1))

{

P1_0=0;

cc++;

if(cc<1000)

{

okflag=1;

}

else if(cc<2000)

{

okflag=0;

}

else

{

errorflag=0;

rightflag=0;

P1_7=1;

cc=0;

oka=0;

okb=0;

okflag=0;

P1_0=1;

}

if(okflag==1)

{

oka++;

if(oka==2)

{

oka=0;

P1_7=~P1_7;

}

}

else

{

okb++;

if(okb==3)

{

okb=0;

P1_7=~P1_7;

}

}

}

 

if(keyoverflag==1)

{

P1_7=~P1_7;

}

}