Email or username:

Password:

Forgot your password?
Marcin's posts Post Back to profile
Top-level
nemo20000

@mwichary Here’s a keyboard you won’t have seen.
Prototype typesetting system. PS2 interface.
14 Feb 2023 at 20:34 | Wall-to-wall | Open on mastodon.online
3 comments
Marcin Wichary replied to nemo20000

@nemo20000 Where could I learn more about this!?

15 Feb 2023 at 2:52 | Open on mastodon.online
nemo20000 replied to Marcin

@mwichary I don’t know. This one came to me from someone who had it in their garage for a long time after getting it from someone else. Professionally made metal case and PCBs with a couple of wire patches. socketed PIC16C73A microcrontroller, 7 other 74 logic chips. Bears the serial number 1015 which suggests a couple of dozen were made.
Numeric keypad and 3×4 above are separate PCBs on ribbon cables but ALL the rest is a single PCB so perhaps there were (intended) options.
192 keys!

15 Feb 2023 at 16:04 | Open on mastodon.online
nemo20000 replied to nemo20000

@mwichary Four LEDs, including “S2” which is one of the red keys on the left.
PS2 to USB interfaces simply can’t cope with the custom PS2 codes produced by the nonstandard keys, resulting in ghosting, persistent held keys and other horrors. I could drag out one of my old machines with a PS2 interface and write a driver, but to what end?
The plan is to replace the PIC with a Pi or equivalent and do a proper USB interface. It’s a good plan and has been for years! One day, one day.

15 Feb 2023 at 16:07 | Open on mastodon.online
Go Up