单片机电子密码锁（可以修改设置密码）——基于51单片机与AT24C02与LCD1602显示其电路图连接如下：本人已经用硬件实验，程序可用。

正确~~本程序特点：装载后读者可以自改密码，然后需要再次载入程序时：可以把主程序aa=Sendstring(0xa0,1,table2,6);这一句去掉。

然后程序的电子锁密码就是你个人设置的密码。

程序代码为：#include<reg51.h>#include<string.h>#include<intrins.h>#define uchar unsigned char#define uint unsigned int#define LCDIO P2#define delay4us() _nop_();_nop_();_nop_();_nop_();uchar buffer[6]={0};sbit sda=P3^7;sbit scl=P3^6;sbit beep=P3^5;bit flag=0,aa; //用户蹲渊义定时溢出标志位uchar DSY_BUFFER[16]=" ";uchar DSY_BUFFER1[16]=" ";uchar Userpassword[6]={0};sbit rs=P0^4;sbit rd=P0^3;sbit lcden=P0^2;sbit led=P3^0;uchar code table2[]="123456";uchar code table[]="Your Password...";void delayms(uint z){uint x,y;for(x=z;x>0;x--)for(y=110;y>0;y--);}void delay() //短延时，两个机器周期,做总线的延时用{;;}void write_com(uchar com){rs=0;rd=0;lcden=0;P2=com;delayms(3);lcden=1;delayms(3);lcden=0;}void write_date(uchar date){rs=1;rd=0;lcden=0;P2=date;delayms(3);lcden=1;delayms(3);lcden=0;}void Display_String(uchar *p,uchar com){ uchar i;write_com(com);for(i=0;i<16;i++){write_date(p[i]);}}void init_lcd(){lcden=0;write_com(0x38);write_com(0x0c);write_com(0x06);write_com(0x01);write_com(0x80);Display_String(table,0x80);Display_String("Lock OK! ",0xc0); }void start(){sda=1;scl=1;delay4us();sda=0;delay4us();scl=0;}void stop(){sda=0;scl=1;delay4us();sda=1;delay4us();scl=0;}void init() //初始化{sda=1;delay();scl=1;delay();}void ack(){sda=0;scl=1;delay4us();scl=0;sda=1;}void noack(){sda=1;scl=1;delay4us();scl=0;sda=0;}uchar recbyte(){uchar i,rd;rd=0x00;sda=1;for(i=0;i<8;i++){scl=1;rd<<=1;rd|=sda;delay4us();scl=0;delay4us();}scl=0;delay4us();return rd;}uchar sendbyte(uchar wd) {uchar i;bit ack0;for(i=0;i<8;i++){sda=(bit)(wd&0x80);_nop_();_nop_();scl=1;delay4us();scl=0;wd<<=1;}delay4us();sda=1;scl=1;delay4us();ack0=!sda;scl=0;delay4us();return ack0;}uchar Recstring(uchar slave,uchar subaddr,uchar *buffer,uchar n) {uchar i;start();if(!sendbyte(slave)) return 0;if(!sendbyte(subaddr)) return 0;start();if(!sendbyte(slave+1)) return 0;for(i=0;i<n-1;i++){buffer[i]=recbyte();ack();}buffer[n-1]=recbyte();noack();stop();return 1;}uchar Sendstring(uchar slave,uchar subaddr,uchar *buffer,uchar n) {uchar i;start();if(!sendbyte(slave)) return 0;if(!sendbyte(subaddr)) return 0;for(i=0;i<n;i++){if(!sendbyte(buffer[i])) return 0;}stop();return 1;}void clear_password(){ uchar i;for(i=0;i<6;i++){Userpassword[i]=' ';}for(i=0;i<16;i++){DSY_BUFFER[i]=' ';}}uchar Keys_Scan(){uchar temp,keynum;P1=0x0F;delayms(5);temp=P1^0x0F;switch(temp){case 1:keynum=0;break;case 2:keynum=1;break;case 4:keynum=2;break;case 8:keynum=3;break;break;}P1=0xF0;delayms(5);temp=P1>>4^0x0F;switch(temp){case 1:keynum+=0;break;case 2:keynum+=4;break;case 4:keynum+=8;break;case 8:keynum+=12;break;break;}delayms(600);return keynum;}void main(){ uchar temp,i=0,j=0,k=0,n;uchar IS_valid_user;beep=1;init();init_lcd();delayms(5);aa=Sendstring(0xa0,1,table2,6);delayms(5);aa=Recstring(0xa0,1,buffer,6);delayms(10);P1=0x0f;while(1){if(P1!=0x0f){temp=Keys_Scan();switch(temp){case 0: case 1: case 2: case 3: case 4:case 5: case 6: case 7: case 8: case 9:if (i<=5) //密码限制在6位以内{Userpassword[i]=temp;DSY_BUFFER[i]='*';Display_String(DSY_BUFFER,0xc0);i++;}break;case 10: //按A键开锁for(k=0;k<6;k++){if(buffer[k]==(Userpassword[k]+48))flag=1;elseflag=0;}if (flag==1){ flag=0;i=0;led=0; //点亮LEDclear_password();Display_String("OPEN OK! ",0xc0);IS_valid_user = 1;j=0;}else{j++;led=1; //关闭LEDclear_password();Display_String("ERROR!Have try ",0xc0);write_com(0xcf);write_date(0x30+j);IS_valid_user=0;}i=0;break;case 11: //按B键上锁led=1;clear_password();Display_String(table,0x80);Display_String("Lock OK! ",0xc0);i=0;IS_valid_user=0;break;case 12: //按C键设置新密码//如果是合法用户则提示输入新密码if ( !IS_valid_user){i=0;Display_String("No rights ! ",0xc0); delayms(1000);Display_String("Your Password...",0x80); Display_String("Lock OK! ",0xc0); }else{i=0;Display_String("New Password: ",0x80);Display_String(" ",0xc0);}break;case 13: //按D键保存新密码if ( !IS_valid_user){ i=0;Display_String("No rights ! ",0xc0);delayms(1000);Display_String("Your Password...",0x80);Display_String("Lock OK! ",0xc0);}else{i = 0;init();delayms(5);for(k=0;k<6;k++){Userpassword[k]=Userpassword[k]+48;}aa=Sendstring(0xa0,1,Userpassword,6);delayms(5);aa=Recstring(0xa0,1,buffer,6);delayms(5);clear_password();Display_String(table,0x00);Display_String("Password Saved! ",0xc0);delayms(1000);Display_String("Do lock agian ? ",0xc0);}break;case 14: //按E键消除所有输入i=0;clear_password();Display_String(" ",0xc0);break;case 15: //清除一位if(i!=0)i--;for(n=0;n<i;n++){DSY_BUFFER1[n]='*';}Display_String(DSY_BUFFER1,0xc0);}P1=0x0f;}if(j==3){ Display_String("THIEF!!!THIEF!!!",0xc0);j=0;beep=0;}}}。