//Program for a simple toll plaza system using low frequency RFID interfaced with 8051 microcontroller (AT89C51)
#include<reg51.h>
#define port P1
#define key P0 // Port for keypad
void memory();
sfr lcd_data_pin=0xA0;
sbit rs = P1^3;
sbit rw = P1^4;
sbit en = P1^5;
sbit col1=key^4;
sbit col2=key^5;
sbit col3=key^6;
sbit row1=key^0;
sbit row2=key^1;
sbit row3=key^2;
sbit row4=key^3;
unsigned int number=0,pointer=1;
unsigned char card_mem[4][12];
unsigned char card_id[12],index=0,key1=0,lcd,print=0,new_user=0,recharge=0,user_index,t,tool=0;
unsigned int amount[4];
unsigned char current_byte = 0,money[6];
unsigned char pos=0,set=0;
void delay(unsigned char count) //Function to provide time delay
{
unsigned int j;
unsigned char i;
for(i=0;i<count;i++)
for(j=0;j<1275;j++);
}
void lcd_command(unsigned char comm) //LCD command funtion
{
lcd_data_pin=comm;
en=1;
rs=0;
rw=0;
delay(1);
en=0;
}
void lcd_data(unsigned char disp) //LCD data function
{
lcd_data_pin=disp;
en=1;
rs=1;
rw=0;
delay(1);
en=0;
}
lcd_string(unsigned char *disp) //LCD string function
{
char x;
for(x=0;disp[x]!=0;x++)
{
lcd_data(disp[x]);
}
}
void lcd_ini() //Function to initialize the LCD
{
lcd_command(0x38);
delay(5);
lcd_command(0x0F);
delay(5);
}
lcd_display(unsigned int val)
{
unsigned char flg=0;
lcd_command(0xCC);
if(val==0)
lcd_data(‘0’);
while(val>0)
{
lcd=val%10;
val=val/10;
lcd_command(0xCC-flg);
lcd_data(lcd+’0′);
flg++;
}
}
void recieve() interrupt 4 //Function to recieve data serialy from RS232
{
card_id[current_byte]=SBUF;
RI=0; // Reset the serial interrupt after recieving the byte
current_byte++;
}
void display(unsigned char value)
{
lcd_command(0x80+pos);
if(value==10)
{
print=1;
}
if(value==12)
{
set=1;
}
if(value<=9)
{
lcd_data(‘0’+value);
money[pos]=value;
pos++;
}
}
check_col1()
{
row1=row2=row3=row4=1;
row1=0;
if(col1==0)
display(1);
row1=1;
row2=0;
if(col1==0)
display(4);
row2=1;
row3=0;
if(col1==0)
display(7);
row3=1;
row4=0;
if(col1==0)
display(10);
row4=1;
}
check_col2()
{
row1=row2=row3=row4=1;
row1=0;
if(col2==0)
display(2);
row1=1;
row2=0;
if(col2==0)
display(5);
row2=1;
row3=0;
if(col2==0)
display(
;
;row3=1;
row4=0;
if(col2==0)
display(0);
row4=1;
}
check_col3()
{
row1=row2=row3=row4=1;
row1=0;
if(col3==0)
display(3);
row1=1;
row2=0;
if(col3==0)
display(6);
row2=1;
row3=0;
if(col3==0)
display(9);
row3=1;
row4=0;
if(col3==0)
display(12);
row4=1;
}
keypad()
{
row1=row2=row3=row4=0;
if(col1==0)
check_col1();
if(col2==0)
check_col2();
if(col3==0)
check_col3();
}
void show()
{
unsigned char count,i,key,val,flag=0,in;
unsigned int balance,j;
TMOD=0x00; //Enable Timer 1
TH1=0x00;
SCON=0x00;
TR1=0;
IE=0x00;
lcd_command(0x01);
val=index;
for(i=0;i<index;i++)
{
key=0;
for(count=0;count<12;count++)
{
if(card_id[count]==card_mem[count])
{
key++;
}
}
if(key==12)
{
flag=1;
if(amount<=10)
{
user_index=i;
lcd_string(“Insuff. balance”);
lcd_command(0xC0);
lcd_string(“Pls recharge”);
delay(250);
lcd_command(0x01);
lcd_string(“To recharge”);
lcd_command(0xC0);
lcd_string(“press *”);
for(in=0;in<250;in++)
{
for(j=0;j<1275;j++)
{
row1=row2=row3=row4=0;
if(col1==0)
{
tool=1;
recharge=1;
t=1;
keypad();
break;
}
}
if(t==1)
break;
}
lcd_command(0x01);
lcd_string(“Pls scan your ID”);
break;
}
if(tool==0)
{
lcd_string(“Thank you User “);
lcd_command(0x8F);
lcd_data(49+i);
delay(250);
lcd_command(0x01);
lcd_string(“Charges 10.00”);
amount=amount-10;
lcd_command(0xC0);
lcd_string(“Amt left “);
balance=amount;
lcd_display(balance);
lcd_command(0xCD);
lcd_string(“.00”);
delay(250);
lcd_command(0x01);
if(amount<=30)
{
user_index=i;
lcd_string(“Pls recharge”);
lcd_command(0xC0);
lcd_string(“your account”);
delay(250);
lcd_command(0x01);
lcd_string(“To recharge”);
lcd_command(0xC0);
lcd_string(“press *”);
for(in=0;in<250;in++)
{
for(j=0;j<1275;j++)
{
row1=row2=row3=row4=0;
if(col1==0)
{
recharge=1;
t=1;
keypad();
break;
}
}
if(t==1)
break;
}
}
}
t=0;
lcd_command(0x01);
lcd_string(“Pls scan your ID”);
break;
}
}
if(flag==0)
{
lcd_string(“Wrong ID”);
delay(100);
}
if(flag==0)
{
lcd_command(0x01);
lcd_string(“New user press *”);
new_user=1;
}
current_byte=0;
tool=0;
TMOD=0x20; //Enable Timer 1
TH1=0xFD;
SCON=0x50;
TR1=1;
IE=0x94;
}
recharge_acc()
{
unsigned char pin;
lcd_command(0x01);
lcd_string(“Pls enter the”);
lcd_command(0xC0);
lcd_string(“Balance”);
delay(250);
lcd_command(0x01);
while(set!=1)
{
keypad();
delay(40);
}
set=0;
lcd_command(0x01);
lcd_string(“Your balance is”);
for(pin=0;pin<=pos;pin++)
{
number=number+money[pos-pin-1]*pointer;
pointer=pointer*10;
}
amount[user_index]=amount[user_index]+number;
lcd_command(0xC0);
lcd_display(amount[user_index]);
lcd_command(0xCD);
lcd_string(“.00”);
delay(250);
lcd_command(0x01);
number=0;
pointer=1;
pos=0;
lcd_string(“Pls scan your ID”);
}
void memory()
{
unsigned char i,key=0,count,pin,try=0;
lcd_command(0x01);
lcd_string(“New user scan ID”);
current_byte=0;
while(current_byte!=12);
for(i=0;i<4;i++)
{
key=0;
for(count=0;count<12;count++)
{
if(card_id[count]==card_mem[count])
{
key++;
}
}
if(key==12)
{
lcd_command(0x01);
lcd_string(“Sorry ! You are”);
lcd_command(0xC0);
lcd_string(“already an user”);
delay(200);
lcd_command(0x01);
lcd_string(“Pls scan your ID”);
key=0;
try=1;
current_byte=0;
break;
}
}
if(key<12 && try==0)
{
key=0;
for(i=0;i<12;i++)
{
card_mem[index]=card_id;
}
current_byte=0;
lcd_command(0x01);
lcd_string(“Pls scan again”);
while(current_byte!=12);
for(i=0;i<12;i++)
{
if(card_mem[index]==card_id)
{
key++;
}
}
current_byte=0;
TMOD=0x00;
TH1=0x00;
SCON=0x00;
TR1=0;
IE=0x00;
if(key==12)
{
lcd_command(0x01);
lcd_string(“Congratulation !”);
lcd_command(0xC0);
lcd_string(“You are User”);
lcd_command(0xCC);
lcd_data(index+49);
delay(250);
lcd_command(0x01);
lcd_string(“Pls enter the”);
lcd_command(0xC0);
lcd_string(“Balance”);
delay(150);
lcd_command(0x01);
while(set!=1)
{
keypad();
delay(40);
}
set=0;
lcd_command(0x01);
lcd_string(“Your balance is”);
for(pin=0;pin<=pos;pin++)
{
number=number+money[pos-pin-1]*pointer;
pointer=pointer*10;
}
lcd_command(0xC0);
lcd_display(number);
lcd_command(0xCD);
lcd_string(“.00”);
amount[index]=number;
delay(250);
lcd_command(0x01);
number=0;
pointer=1;
pos=0;
lcd_string(“Pls scan your ID”);
}
else
{
lcd_command(0x01);
lcd_string(“ERROR”);
delay(200);
for(i=0;i<12;i++)
{
card_mem[index]=0;
}
lcd_command(0x01);
lcd_string(“Pls scan your ID”);
}
if(key==12)
index++;
}
TMOD=0x20; //Enable Timer 1
TH1=0xFD;
SCON=0x50;
TR1=1;
IE=0x94;
}
void main()
{
col1=col2=col3=1;
TMOD=0x20;
TH1=0xFD;
SCON=0x50;
TR1=1;
IE=0x94;
lcd_ini(); //Place cursor to second position of first line
lcd_string(“Pls scan your ID”);
while(1)
{
row1=row2=row3=row4=0;
if(col1==0)
{
keypad();
}
if(print==1 && new_user==1)
{
memory();
print=0;
new_user=0;
}
if(print==1 && recharge==1)
{
recharge_acc();
print=0;
recharge=0;
}
if(current_byte==12)
{
show();
}
}
}