Software: KEIL micro vision 4.0
Simulator :Proteus 8.0
Circuit diagram:
Circuit Working:
I have connected four rows of keypad to p3.0 to p3.2 respectively and three columns of keypad are connected to p3.4 to p3.7 respectively.Lcd data pins are connected to port 1.Lcd control signals such as RS,R/W and EN are connected to p2.0 to p2.2 respectively.
Whenever user entered the password then that password is get checked by the microcontroller.If the password is correct then lcd displays the message of "access granted".If password is wrong then lcd displays the message of "access denied".
Program:
Header file of LCD:
#include<reg51.h>
#include<string.h>
sbit RS = P2^0; // REGISTER SELECT
sbit RW = P2^1; // READ/WRITE
sbit EN = P2^2; // ENABLE
void delay(int t); //delay function
void lcd_init(void); //initialization of lcd
void lcd_command(char c); // lcd command function
void lcd_data(char d); //lcd data function
void str(char a[]); // lcd string function
void lcd_init(void)
{
lcd_command(0x38); //8 bit,2 line,5x7 dots
lcd_command(0x01); // clear dispay
lcd_command(0x0f); //display on,cursor blinking
lcd_command(0x06); // entry mode
lcd_command(0x80); // force cursor to begining of first row
}
void lcd_command(char c)
{
P1=c; //send command to port1
RS=0; //select command register to send command
RW=0; // write operation
EN=1; // send high to low pulse on enable pin of lcd
delay(5);
EN=0;
delay(5); // delay
}
void lcd_data(char d)
{
P1=d; //send data to port1
RS=1; //select data register to send data
RW=0; // write operation
EN=1; // send high to low pulse on enable pin of lcd
delay(5);
EN=0;
delay(5); // delay
}
void delay(int t)
{
int j;
for(j=0;j<t*1275;j++);
}
void str(char a[])
{
int j;
for(j=0;a[j]!='\0';j++)
{
lcd_data(a[j]); //pass string to array
}
}
Main program:
#include<reg51.h>
#include<string.h>
#include "lcd.h"
sbit r1=P3^0;
sbit r2=P3^1;
sbit r3=P3^2;
sbit r4=P3^3;
sbit c1=P3^4;
sbit c2=P3^5;
sbit c3=P3^6;
int i=0;
char pass[4]="1234"; //password
char b[4]; // array for storing the data entered by the user
void keypad();
void welcome();
void main()
{
lcd_init(); //initialization of lcd
str("welcome to the");
lcd_command(0xc0);
str("embedded system");
lcd_command(0x01);
lcd_command(0x80);
while(1)
{
keypad(); // take input from user
if((strncmp(pass,b,4))==0) //check the password
{
lcd_command(0x01);
str("access granted"); //password is correct
lcd_command(0x01);
}
else
{
lcd_command(0x01);
str("access denied"); //password is wrong
lcd_command(0x01);
}
}
}
void keypad() //keypad function to take input from user
{
int i;
str("enter password");
lcd_command(0xc0);
while(i<4) // take 4 bit password
{
r1=0;
r2=r3=r4=1;
if(c1==0)
{
lcd_data('*');
b[i]='1';
i++;
}
else if(c2==0)
{
lcd_data('*');
b[i]='2';
i++;
}
else if(c3==0)
{
lcd_data('*');
b[i]='3';
i++;
}
r2=0;
r1=r3=r4=1;
if(c1==0)
{
lcd_data('*');
b[i]='4';
i++;
}
else if(c2==0)
{
lcd_data('*');
b[i]='5';
i++;
}
else if(c3==0)
{
lcd_data('*');
b[i]='6';
i++;
}
r3=0;
r2=r1=r4=1;
if(c1==0)
{
lcd_data('*');
b[i]='7';
i++;
}
else if(c2==0)
{
lcd_data('*');
b[i]='8';
i++;
}
else if(c3==0)
{
lcd_data('*');
b[i]='9';
i++;
}
r4=0;
r2=r3=r1=1;
if(c1==0)
{
lcd_data('*');
b[i]='*';
i++;
}
else if(c2==0)
{
lcd_data('*');
b[i]='0';
i++;
}
else if(c3==0)
{
lcd_data('*');
b[i]='#';
i++;
}
}
}
Program Description:
First I have initialized the lcd by providing lcd initialization function.Then I have called keypad function.Keypad function is used to take input from the user.I have stored the data entered by the user in one array.After that I compared this data with the stored password.If the password get matched with the data entered by the user then lcd will display the message of "access granted".If it does not get match then lcd will display the message of "access denied".For a continuous process,I have used while loop.For displaying the data lcd data function is used.
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