EE 476: Laboratory 3

The game "Simon"

"Simon" is a sequence matching game. The game flashes an LED and plays a tone. The human has to press the button associated with the LED (and tone). If the human presses the correct button, then the game repeats the first event and adds a second event. The human must now match the two events. If the human presses the correct sequence of two buttons, the game repeats them and adds a third event. There is a time limit for human response, perhaps one second per button push. When the human presses a correct button, the appropriate tone is played and the LED lights. If the human makes a mistake, the game produces a rude sound, flashes all the LEDs and stops until it is reset.

You will construct such a game using four of the LEDs and buttons on the development board and a earphone (or speaker) which you attach to one output bit.

You can generate specific audio frequencies using an interrupt-driven scheme like the one described in Lab 1, but with variable timer reload values. One of the portD or portB pins will be used to drive an earphone. The ports can drive the earphone directly, but you can make it louder with a 74xx driver or an opamp. You could also use amplified speakers or your own earphones.

Write a program which implements Simon.
Specifications:

• The tones produced should be the following:

          C4   262 Hz (middle C)
          D4   294
  	E4   330
  	F4   349
  

• The tone duration may be fixed. Choose a length you can play.
• There should be a short slient period between tones.
• After the game finishes a sequence, the human has about 2 seconds to start responding, then one second per button press after that.
• The sound associated with a human error should be below middle C, perhaps 140 Hz. You can make it less pleasant to listen to by varying the length of each time cycle while the sound is playing.
• After the human makes a mistake, display the length of the last correct sequence on the LEDs and wait for a reset.
• Since there are only 32 bytes of RAM on the AT90S1200, you may find that you need to do some bit-packing to keep a table of the past sequence.

You will demonstrate the game to a staff member. Be sure to point out any enhancements you have made such as variable speed, introductory tunes, or better error noises.

Your written lab report should include:

• The scheme you used to detect the pushbutton state. (e.g. polling loop, interrupt)
• How you generated the freqencies and how you know they are accurate.
• Other design aspects of the assignment (e.g. did you use table lookup for the frequencies or did you hardcode them).
• A schematic of any circuitry that you built.
• A heavily commented listing of your code.