说明：开机启动就是上图这样的，密码正确显示P（pass）,密码错误显示E（error）

#include "reg51.h"
#include "myheader.h"
#define uchar unsigned char
long int sleep_i=0;
int pwd[4]={0,1,2,3};
int i=0;
int buffer[4]={0};
void test()
{
	P17=0;
}
void judge(int buffer[4],int pwd[4])
{
	uchar pass=1;
	uchar i=0;
	for(i=0;i<4;i++)
	{
		if(buffer[i]!=pwd[i])
			pass=0;
	}
	if(pass==1){P2=0XFF;P20=P21=P24=P25=P26=P27=0;sleep(5000);P2=0XFF;P27=0;}
	else {P2=0;P21=P22=1;sleep(5000);P2=0XFF;P27=0;}
}

void main()
{
	uchar num[10]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};
	while(1)
	{
		P26=0;	
		if(P3!=0XFF)
		{
			sleep(1200);
			if(P30==0){buffer[i]=0;};
			if(P31==0){buffer[i]=1;};			
			if(P32==0){buffer[i]=2;};
			if(P33==0){buffer[i]=3;};
			while(P3!=0XFF);
			i++;
			if(i==4){i=0;judge(buffer,pwd);};
		}
		
	}
	
}

void sleep(long int a)
{
	for(sleep_i=0;sleep_i<a;sleep_i++)
	{
		;
	}
}