A Brief Description: You will design a simple door lock system that's controlling the motion of garage door (open, close). In this lock design, the code locks to open the garage door is "4567".if there is any urgent case the door is opened without password. Hardware (as the above design): 1. Insert the code of the door using 4X3 keypad. 2. Show the message on the Virtual terminal. 3. Represent the door by one led, door is "open ---- 4. Represent the Urgent sensor by switch. -led is ON", "close ------led is OFF". How door lock works: 1. A message "Welcome" will display on Virtual terminal at first row. 2. Second row display "please enter the code:" it asked you to enter password to open the door. 3. If you entered the correct code then the garage door will open. it's open for 20 seconds then close "You must generate 20 seconds delay by using timero, configure the pic16f877a to run at 16KHz. configure Timero to overflow every 1 count set the prescaler to 256." 4.If code you entered is not correct on then led door is not turn on, display "insert a correct code" message on VT and start the program from step 1 again. 5.If urgent case is appeared open the garage door, urgent case is connected with external interrupt "RBO