Using LEDs, LCDs and GLCDs in Microcontroller Projects

11.8 PROJECT 11.8 – The High/Low Game

This project uses a 4 × 4 keypad to create the classical a High/Low game. For those of you who are not familiar with the game, here are the rules for this version of the game:

• The computer will generate a secret random number between 1 and 32 767.
• The top row of the LCD will display ‘Guess Now . . .’
• The player will try to guess what the number is, by entering a number on the keypad and then pressing the ENTER key.
• If the guessed number is higher than the secret number, the bottom row of the LCD will display ‘HIGH – Try Again’.
• If the guessed number is lower than the secret number, the bottom row of the LCD will display ‘LOW – Try Again’.
• If the player guesses the number, then the bottom row will display ‘Well Done . . .’
• The program waits for 5 seconds and the game re-starts automatically.

Before going into the design of the project, it is worthwhile to learn a bit more about how the keypads work and the mikroC Pro for PIC commands available to use a keypad.

11.8.1 Keypads

A 4 × 4 keypad consists of 16 keys with internal mechanical switches at each key position. Figure 11.32 shows a typical 4 × 4 keypad connected to PORT D of a PIC microcontroller.

Figure 11.32 A 4 × 4 keypad connected to a microcontroller

The keypad operates on the principle of ‘scan and detect’, where in Figure 11.32, RD0, RD1, RD2 and RD3 are configured as inputs and ...