Overview

The purpose of this lab is to gain some experience with input, output, and subroutine calls.

Problem Statement

In this lab, you will design, code, assemble, simulate, download and run a program. The program is similar to last week's assignment in that it will cause the LEDs to flash to the left or right. This week your program must exihibit the following behavior:

1. Rotate the LEDs to the right continuously until a switch is pressed.
2. When a switch is pressed, the LEDs should rotate in the opposite direction.
3. While rotating, each LED should remain on for 0.25 seconds.

Program Notes:

• You must make use of subroutine(s) for the delay loop(s).
• One and only one LED should be on at any point in time.
• You are not allowed to use a look-up table for this program.
• The direction of the LED rotation should change immediately after the state the switch changes (at least within 0.25 seconds). This means that the switch has to be checked after each output.

Pre-laboratory activity (due on entering the week 4 lab)

Write a delay loop subroutine that has a duration of exactly 0.25 seconds. You should include the time required to call and return from the loop in the 0.25 seconds. Your paper submission should include your timing calculations in addition to your code listing.

Laboratory Demonstration (due 11pm the day prior to week 5 lab)

You must demonstrate your program working on your board and use the oscilloscope to show that your delay loop duration is accurate.

Laboratory Report (due 11pm the day prior to week 5 lab)

You should submit the .lst for your program using the online submission form.

• Add .nolist before and .list after the .include "m32def.inc" in your .asm file
• The beginning of your source file should contain:
  • Your name
  • Submission date
  • Program name
  • "Lab 3"
  • A brief (couple sentences) description of something interesting you discovered while working on this assignment

In addtion, you must log the time you spent on this assignment (including the pre-laboratory activity) in FAST.

Acknowledgment

This assignment is based on a similar assignment developed by Prof. William Barnekow.

© 2001-2007 Dr. Christopher C. Taylor

Office: L-343

Phone: 277-7339