Denial

The Commodore VIC-20 was used at the National Aeronautics and Space Administration as a small computer interface to a stepper motor. See the .pdf at

https://ntrs.nasa.gov/citations/19870007537

Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan

I got across this quite some years ago, in 2007, and mentioned it in the thread "Space Exploration" in the Off Topics section.

Unfortunately, the original link in that post doesn't work anymore (according to archive.org it must have disappeared around 2018), but archive.org made a copy in 2008, see here:

https://web.archive.org/web/20081208205 ... 007537.pdf

Greetings,

Michael

Wow, impressive! I forgot that Mike had already noticed that. Wonder in which context the VIC and the stepper motor were used. Maybe a VIC was sent in orbit onboard a space shuttle? It would have been a small step for a computer... oh well

Also, why didn't they use a simple vic-rel or a similar user port interface, widely available at the time?

IIRC, VIC REL provided 8 relay outputs, but no input. The stepper interface however uses (only) 4 outputs to operate the stepper, the other four are input and sense the zero position (fine and 'coarse') of stepper axis and turntable, the latter which is connected to the stepper over a gearbox.

The included program is likely 'proof-of-concept'. The intended application most probably was rotating a workpiece on said turntable, so tools could reach it from a single direction. Rotating the workpiece at a bearable speed surely required a translation of the program to machine code.

Mike wrote: ↑Sun Mar 14, 2021 2:38 pm IIRC, VIC REL provided 8 relay outputs, but no input.

VIC-REL has 6 outputs and 2 inputs but the manual specifically warns against directly using loads such as motors.