数字密码锁的设计方案

设计要求：

1)   通过程序预先设置4位数字作为开锁密码

2)   按键为0~9数字键、退位键、开锁键等，用4位数码管显示输入的数字

3)   先通过按钮输入4位密码，再按开锁键；如密码正确，绿色指示灯亮，锁打开；密码错误，红色指示灯亮，蜂鸣器报警，一秒钟后停止。连续3次密码错误，红色指示灯闪烁5秒，蜂鸣器报警（另一种频率的声响）

4)   连续3次输入密码错误，系统锁定，可设定为30秒后自动解锁或通过输入管理员密码解锁

电路组成：5V电源+51单片机最小系统+LCD1602显示屏+4*4矩阵键盘+无源蜂鸣器

1602LCD驱动

/*-----------------------------------------------
  ���ƣ�LCD1602
  ���Ŷ������£�1-VSS 2-VDD 3-V0 4-RS 5-R/W 6-E 7-14 DB0-DB7 15-BLA 16-BLK
------------------------------------------------*/
#include "1602.h"
#include "delay.h"

#define CHECK_BUSY

sbit RS = P2^4;   //����˿� 
sbit RW = P2^5;
sbit EN = P2^6;

#define RS_CLR RS=0 
#define RS_SET RS=1

#define RW_CLR RW=0 
#define RW_SET RW=1 

#define EN_CLR EN=0
#define EN_SET EN=1

#define DataPort P0

/*------------------------------------------------
              �����
------------------------------------------------*/
 bit LCD_Check_Busy(void) 
 { 
#ifdef CHECK_BUSY
 DataPort= 0xFF; 
 RS_CLR; 
 RW_SET; 
 EN_CLR; 
 _nop_(); 
 EN_SET;
 return (bit)(DataPort & 0x80);
#else
 return 0;
#endif
 }
/*------------------------------------------------
              д�������
------------------------------------------------*/
 void LCD_Write_Com(unsigned char com) 
 {  
 while(LCD_Check_Busy()); //æ��ȴ�
 RS_CLR; 
 RW_CLR; 
 EN_SET; 
 DataPort= com; 
 _nop_(); 
 EN_CLR;
 }
/*------------------------------------------------
              д�����ݺ���
------------------------------------------------*/
 void LCD_Write_Data(unsigned char Data) 
 { 
 while(LCD_Check_Busy()); //æ��ȴ�
 RS_SET; 
 RW_CLR; 
 EN_SET; 
 DataPort= Data; 
 _nop_();
 EN_CLR;
 }

/*------------------------------------------------
                ��������
------------------------------------------------*/
 void LCD_Clear(void) 
 { 
 LCD_Write_Com(0x01); 
 DelayMs(5);
 }
/*------------------------------------------------
              д���ַ�������
------------------------------------------------*/
 void LCD_Write_String(unsigned char x,unsigned char y,unsigned char *s) 
 {     
       
 while (*s) 
   {     
 LCD_Write_Char(x,y,*s);     
 s ++;  x++;   
   }
 }
/*------------------------------------------------
              д���ַ�����
------------------------------------------------*/
void LCD_Write_Char(unsigned char x,unsigned char y,unsigned char Data) 
 {     
 if (y == 0) 
   {     
   LCD_Write_Com(0x80 + x);     
   }    
 else 
   {     
   LCD_Write_Com(0xC0 + x);     
   }        
 LCD_Write_Data( Data);  
 }
/*------------------------------------------------
              ��ʼ������
------------------------------------------------*/
 void LCD_Init(void) 
 {
   LCD_Write_Com(0x38);    /*��ʾģʽ����*/ 
   DelayMs(5); 
   LCD_Write_Com(0x38); 
   DelayMs(5); 
   LCD_Write_Com(0x38); 
   DelayMs(5); 
   LCD_Write_Com(0x38);  
   LCD_Write_Com(0x08);    /*��ʾ�ر�*/ 
   LCD_Write_Com(0x01);    /*��ʾ����*/ 
   LCD_Write_Com(0x06);    /*��ʾ����ƶ�����*/ 
   DelayMs(5); 
   LCD_Write_Com(0x0C);    /*��ʾ�����������*/
   }