Universal Retro keyboard
Posted: Tue Jun 25, 2019 7:47 pm
Now that we have Klyball's 542C recreation in addition to the original 542 recreation keyboard, there's not much of a void in the OSI keyboard area anymore. But, many of us also have other vintage machines that use ASCII keyboards. For that matter, so did the older OSI machines.
I've been meaning to put together a (semi) universal ASCII keyboard for vintage computers. I decided to use KiCad rather than my tried and true Altium so that the result would be available to be modified by anyone. Last night, I bit the bullet and plowed through the KiCad learning curve, and managed to get the first cut, which I have on GitHub.
The first cut is basically an OSI 542 vanilla polled keyboard, but I've replaced the 8T26's with a pair of 74LS240's, and the 7475's with a 74LS373. (HC parts will fine as well). I've left room to escape the connector to a blank area of the board, which can be used for extra functions such as:
I would appreciate any feedback. I'll probably throw in an AVR or PIC and create a stabilizer PCB before sending it off in the next few days.
Cheers,
Dave
[edited 6/21/20 to update Github link to current GitHub repo.]
I've been meaning to put together a (semi) universal ASCII keyboard for vintage computers. I decided to use KiCad rather than my tried and true Altium so that the result would be available to be modified by anyone. Last night, I bit the bullet and plowed through the KiCad learning curve, and managed to get the first cut, which I have on GitHub.
The first cut is basically an OSI 542 vanilla polled keyboard, but I've replaced the 8T26's with a pair of 74LS240's, and the 7475's with a 74LS373. (HC parts will fine as well). I've left room to escape the connector to a blank area of the board, which can be used for extra functions such as:
- Module to provide advanced features of 542B/C, which can also be added to stock 542 keyboards (compatible with 16-pin header)
- Shift-lock emulation
- ASCII keyboard emulation with parallel out
- Different polled keyboard emulation (using a 2-port RAM)
- Serial keyboard emulation with PS/2 or USB interface
I would appreciate any feedback. I'll probably throw in an AVR or PIC and create a stabilizer PCB before sending it off in the next few days.
Cheers,
Dave
[edited 6/21/20 to update Github link to current GitHub repo.]