Single chip electronic password lock with password change

4*4 keyboard input, can change password, 24C02 is used to store password. I use 6 digits. You can also use more digits by changing the corresponding variables. It's very simple. I have written the initial password 2 3 4 6 7 0 in 24C02 in advance. Debugging is successful and can be used directly. STC89C51RC single chip microcomputer, universal board welding
    // The data {2,3,4,6,7,0} has been written to 24C02 on the experimental board
#include
#include
#define uchar unsigned char
#define uint unsigned int
char code SKEY[16]={4,8,11,15,3,7,10,14,2,6,0,13,1,5,9,12};
char code act[4]={0xfe,0xfd,0xfb,0xf7};
char data rd[6]={1,9,8,5,1,1};
char ct=0;
sbit contel=P2^1;
sbit cin=P0^3;
sbit set=P0^4;
sbit wrong=P0^5;  
sbit SDA=P2^6;
sbit SCL=P2^7;
bdata char com_data;
sbit mos_bit=com_data^7;
sbit low_bit=com_data^0;
void delay_iic(int n);
uchar rd_24c01(char a);
void wr_24c01(char a,char b); 
void wtsec(); 
/**************************************/
void delay_iic(int n)
{
int
for(i= 1;i}
void delay(unsigned int k)
{
unsigned int data i,j;
for(i=0;i{
for(j=0;j<121;j++)
{;}
}
}
//************************************
void start()
{
SDA=1;_nop_();_nop_();_nop_();_nop_();
SCL=1;_nop_();_nop_();_nop_();_nop_(); SDA
=0;_nop_();_nop_();_nop_();_nop_( ) ;
_();_nop_();_nop_ ();_nop_(); SCL = 1 ;_nop_();_nop_();_nop_();
_ nop_(); _nop_() ;_nop_() ; SCL=0;_nop_();_nop_();_nop_();_nop_(); } //****************************** void shift8(char a) { data uchar i; com_data=a; for(i=0;i<8;i++) { SDA=mos_bit; SCL=1;_nop_();_nop_();_nop_();_nop_();_nop_();_ nop_(); SCL=0;_nop_();_nop_();_nop_();_nop_();_nop_();_nop_(); com_data=com_data*2; } } //****************** uchar rd_24c01(char a) { data uchar i,command; SDA=1;_nop_();_nop_();_nop_();_no p_(); SCL=0;_nop_();_nop_();_nop_();_nop_(); start(); command=160; shift8(command); ack(); shift8(a); ack(); start(); command=161; shift8(command); ack(); SDA=1;_nop_();_nop_();_nop_();_nop_(); for(i=0;i<8;i++) {













































com_data=com_data*2;
SCL=1;_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
low_bit=SDA;
SCL=0;_nop_();_nop_(); _nop_();_nop_();_nop_();_nop_();
}
stop();
return(com_data);
}
//******************
void wr_24c01(char a,char b)
{
data uchar command;
_nop_();_nop_();_nop_();_nop_();_nop_();
SDA=1;_nop_();_nop_();_nop_();_nop_();
SCL=0;_nop_();_nop_();_nop_();_nop_();
start();
command=160;
shift8(command);
ack();
shift8(a);
ack();
shift8(b);
ack();
stop();
_nop_();_nop_();_nop_();_nop_();_nop_();
}
//Keyboard Scan
char scan_key(void)
{
char i,j,in,ini=0,inj=0,temp,del;
bit find=0;
 P1=0x0f; 
 temp=P1;
 if(temp!=0x0f) //The key is pressed Release 
for(del=10;del>0;del--); //Keyboard debounce delay
if(temp!=0x0f)
{
 for(i=0;i<4;i++)
 {
 P1=act;
 in =P1;
 in=in>>4;
 in=in|0xf0;
  for(j=0;j<4;j++)
  {
    if(act[j]==in)
    {find=1;
    inj=j;ini= i;
    }
  }
 }
}
 if(find==0)return -1;
 return (ini*4+inj);
}
//Input function
void put_secret()
{
char wrt[6];
char et,ft;
char wt,x=1; 
char * p,*t;
p=rd;
t=wrt;
for(wt=0;wt<6;) 
{
 et=scan_key();
if(et!=-1)
{
wrt[wt]=SKEY[et];
wt=wt+x;
cin=0;
delay(200);
cin=1;
}
}
ct=0;
for (ft=0;ft<6;)
{
if(wrt==rd)
{ct=ct+x ; }
ft=ft+x;
}
if(ct==6)
 contel=1;
else 
wrong=0;
}
 void wtsec()
  {
char t[6];
char e,f,i=10;
char w,x =1; 
char *m,*n;
m=rd;
n=t;
for(w=0;w<6;) 
{
 e=scan_key();
if(e!=-1)
{
t[w]=SKEY[e] ;
w=w+x;
cin=0;
delay(200);
cin=1;
}       
}
for (f=0;f<6;)
{
wr_24c01(i,t[f]);
delay_iic(250);
rd [f]=rd_24c01(i);
delay_iic(250);
f=f+x;
i=i+x;
}       
  }
//==================== ========
void main(void)
{
char c,f, key_val,x=1,ii=10;
contel=0;
wrong=1;
cin=1;
set=0; 
delay(2000);
for (f=0;f<6;)
{
rd[ f]=rd_24c01(ii);
delay_iic(250);
f=f+x;
ii=ii+x;
}
set=1;
delay(1000);
 while(1)
 {  
 c=scan_key();
   if(c! =-1) 
   key_val=SKEY[c];
   switch(key_val)  
    {  
   case 12:cin=0;delay(1000);cin=1;put_secret();break ;
      case 13:ct=0;wrong=1;contel =0;cin=1;set=1;break;  
      case 14:if(ct==6){set=0;wtsec();set=1;} set=1;ct=0;break;
      default:break ;
}
}
}