Project Suggestions using 8255 PPI, sensors to IBM ?

Google is your friend. Search with 8255 as a search word.

It's really a dead simple chip to use. One 8-bit bidirectional data bus, two address bits, /WR and /RD signals. You can tie reset and chip select to inactive levels.

Use a bidirectional printer port. Look at Jan Axelson's site (google) for parallel port info. Get the data sheet on the 82C55A and you're off..

Best regards, Spehro Pefhany

Google around for stepper motor driving and 8255 as the keys. Probably find lots of stuff. By the way, DONT try to drive the stepper motor directly with the 8255. You need to build or buy a driver circuit.

The simplest sensor to use with a stepper motor would be a limit switch. Motor linkage moves something and you need limit switches to stop or reverse direction. You could simulate 1 or 2 axis of an automated milling machine.

Another good sensor would be to add an encoder wheel to the stepper motor and count revolutions and write code so you can control the acceleration/velocity profile of the motor. Even better would be adding a little bit of adjustable drag to the motor to simulate a variable load. A simple variable drag would be to use the shaft of the motor (or some linkage to the shaft) to wind up a string with a little bucket and sand.

You can outline a whole system for your project, make it very ambitious but then for the actual hardware part you choose some key sub-system to implement that demonstrates your knowledge. I can almost guarantee that any project you pick will quickly grow out of hand and you will be hard pressed to finish it so choose carefully what you write in your project proposal as actual work versus a discussion of the concept and the "big-picture".

Rob Young snipped-for-privacy@ieee.nospamplease.org