Project 3: Digital I/O and Timing

• All components of the project are due by March 3rd at 5:00pm.
• Two person groups are required

Project Goals

• Create, compile, and download code to the Atmel Mega8, and
• Manipulate digital I/O lines

Project Components

• Implement an internal 4-bit counter.
• The state of the counter is indicated using 4 LED channels:
  • Bit 0: Blue
  • Bit 1: Green
  • Bit 2: Red
  • Bit 3: Yellow
• Each time the button is released, the counter should increment.
  • If it was in a state of 0xf, then it should roll over to 0x0.
  • Make sure that you perform proper debouncing on both the press and release events.

• Produce a musical tone using the speaker. This tone should be produced continuously (no pauses). Note that tones can be produced by turning the speaker "on" and "off" at some frequency.
• The frequency of the tone should increase with higher counter values. (alternatively, you could play one bar of Yankee Doodle with each counter value)

Things You Should Know

• There are three debugging LEDs (red, green, and yellow) attached to PORTB, pins 0, 1, 2
• The blue LEDs are all attached to PORTC, pin 5
• The piezoelectric speaker is attached to PORTD, pin 2
• Switch 1 is the reset switch (pushing it will cause the processor to reboot)
• Switch 2 is attached to PORTD, pin 3. This pin will read 1 when the button is not pressed and 0 when it is pressed.

References:

• Atmel HOWTO
• Frequencies of musical tones. Note that you will only be able to approximate these frequencies

Implementation Notes

• Modularize your code: keep routines simple. For example, you should separate the counting process from the LED state changes (i.e., we expect you to implement a DisplayCounter() function that is responsible for updating the state of the LEDs)
• Switches are noisy (as we have discussed). Make sure that you use software debouncing (this will be tested)

What to Hand In

• Group report: Turn in your documented code to the project 3 digital dropbox on D2L (text format). Only hand in one copy of code per 2-person group.
• Group demonstration: Demonstrate your working implementation to either a TA or the instructor). This demonstration is due at the same time as the reports.
• Personal report: State the relative contribution of you and your partner (in terms of percentage of effort) (text format only!)

Grading

• 50%: Project implementation
• 25%: Demonstration of working project
• 25%: Internal documentation of the code

fagg [[at]] ou.edu

Last modified: Wed Feb 11 00:19:16 2009