Password protect your microcontroller

Hello friends, a good idea of privileging the execution of main program of microcontroller came in my mind after watching a Si-Fi movie……and I did it………

Password protecting your microcontroller is one of the coolest things you can do with it……

I created a routine that reads 5 keystrokes and then checks weather the inserted password is right or not.

the micro controller here used is  Atmega 8535

 Not discussing much more about logic, here is the program

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void main()

{

  unsigned char a,b,c,d,e;           

  DDRA=0x00;

  PORTA=0xff;

                               //ask for password

 while(1)

 {

  lcd_init();

  lcd_string("Enter a 5 digit");

  lcd_gotoxy(1,0);

  lcd_string("Password:");

                                             //read password

  while(PINA==0xff);                    //if all keys open stay here

  a=PINA;

  delayms(200);

    lcd_gotoxy(1,0);

            lcd_string("Password:*");

            while((PINA&0xf0)!=0xf0);      //wait to release the key

 while(PINA==0xff);        

             b=PINA;

  delayms(200);

    lcd_gotoxy(1,0);

            lcd_string("Password:**");

            while((PINA&0xf0)!=0xf0);     //wait to release the key

 while(PINA==0xff);        

             c=PINA;

  delayms(200);

    lcd_gotoxy(1,0);

            lcd_string("Password:***");

             while((PINA&0xf0)!=0xf0);   //wait to release the key

 while(PINA==0xff);        

 d=PINA;

  delayms(200);

    lcd_gotoxy(1,0);

            lcd_string("Password:****");

            while((PINA&0xf0)!=0xf0);   //wait to release the key

 while(PINA==0xff);        

             e=PINA;

  delayms(200);

    lcd_gotoxy(1,0);

            lcd_string("Password:*****");   //wait to release the key

              

                                   //checking the password

  if(a==0xef)

  {

  if(b==0xdf)

            {

            if(c==0xbf)

               {if(d==0x7f)

                        {

                                    if(e==0xef)

                                    {

                                    lcd_init();

                                    lcd_string("Welcome");

                                    goto wait;

                                    }

                                    else

                                    {

                                                            lcd_init();

                                                            lcd_string("Invalid password!!");

                                                            delayms(2000);

                                    }

                        }

                        else

                        {

                                                lcd_init();

                                                lcd_string("Invalid password!!");

                                                delayms(2000);

                        }

            }

            else

            {

            lcd_init();

            lcd_string("Invalid password!!");

            delayms(2000);

            }

            }

   else

  {

  lcd_init();

  lcd_string("Invalid password!!");

  delayms(2000);

  }

  }

 else

  {

  lcd_init();

  lcd_string("Invalid password!!");

  delayms(2000);

  }

  }

  wait:while(1);                      

            }

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leave a comment if you want to ask any thing related to programming.

:)