I had been playing with the idea of reading a PS2 mouse but that became cumbersome. When I realized that an old joystick had the pots directly available at the connector, it seemed like it was worth a try.

Actually there are two answers to your question, I have two tables. One is a small one, roughly 6"x 6" x 6" that uses steppers without feedback. Built it primarily for engraving nameplates and printed circuit boards. Mostly proof of concept. it currently runs 200 step motors at 1/2 step, and I don't need to control that one manually.It uses some kit stepper drives that I built. but I may upgrade to Gecko 201's and have a fractional step choice later.

The larger one is a 4' x 6' gantry with servos. Both tables are primarily controlled by PC running Mach3, but on the gantry, I wanted a way to do some manual moves for artistic uses. I could use a Manual Pulse Generator through Mach3, but this seemed an interesting way to experiment and have a intuitive way to control 2 axises at once. The beauty of the drive system that I have built is that either one uses Step/Direction control. The servo table uses Gecko 340 drives.

Timing on the PIC is "whatever works". Since the 18F2331 will run at 40MHz, I should have enough. I was thinking about the 500 range on either side also. Seems to give some deadband without wasting too much control. The third pot (trim on the joystick) will be used as a modifier in the math to control the overall speed so that I can tailor the response to the job at hand.