DUE DATE: Wednesday, March 13, 2002, at NOON to my mailbox in HRN 545

(no late submissions accepted!!!)

Summary

This project introduces students to direct hardware I/O programming on IBM PC computers, writing a replacement Interrupt Service Routine, and using timing services provided by the 8254 Programmable Interval Timer.

Your task is to write an installable alarm program, scheduled to play sound on the PC speaker at the specified time. Your program should have the following features:

• Allow the user to enter time (in hours and minutes) when the alarm will be triggered at startup. It should accept time in either standard format (1-12, am/pm) or military time (0-24). Display a message giving the user some instructions.
• Play some interesting music when the alarm goes off. If you are like me, and lack any musical talents, playing the musical scale from one of our examples will suffice. It should, however, be more fun than just a single tone.
• Allow the user to toggle the alarm on and off using the ALT-A key combination. In addition, if the alarm has been triggered, turning it off with ALT-A should also stop any sound playing.
• If the alarm is not turned off, it should stop playing sound after one minute.
• Include some sort of a status display, so that the user knows whether the alarm is on.
• In addition, the alarm should function as a clock, continuosly displaying current time of day in the upper right-hand corner of the screen.

Notes

• In order for your program to stay in memory but allow DOS to return to the command prompt, it will have to be designed as a TSR (Terminate and Stay Resident utility.) Use DOS function 31h of int 21h to accomplish this.
• To properly keep track of time, your program would have to hook one of the timer tick interrupt routines. It is recommended that you use int 1Ch to make it easier.
• To properly catch any key presses, you program would also have to hook the keyboard interrupt (int 9).
• Turning the alarm off once it has been triggered, and then turning it back on within one minute should NOT re-trigger it.
• Standard project guidelines apply: be neat, write comments, check for errors.
• Turn in your assignment ON TIME. If it is not in my mailbox at noon on the due date, it is late, and therefore not accepted. Period. Slip it under my door of HRN 539 if the office is closed.

Extra Credit

• (15 pts) Add SNOOZE functionality to your alarm that can be triggered by hitting ALT-S key combination. Use a 10 second snooze time period, that is if the user hits SNOOZE, the alarm should stop playing sound for 10 seconds, and then start plaing it again until the user turns it off with ALT-A. Note: in order to receive extra credit, the main assignment has to be completely functional. In other words, don't leave out a required part but do the extra credit instead.

What to turn in

A printout of your code and a floppy disk containing your source file and resulting binaries. You may also use the submit directories, if you wish. However, please turn in a hard copy of your source code in either case.