Geneve XT keyboard interface

[pnr]

As far as I can tell from the schematics, the Geneve uses a software driver to interface with the XT keyboard: the hardware interface is nothing more than two output cru lines connected to pull-down transistors, an input cru line for data and the clock line connected to an interrupt.

 

Does anybody have a copy of the MDOS keyboard driver code for this handy? I know MDOS650 is on whtech, but it is all ark'ed up and perhaps a forum member has plain text source code handy (and knows where to look for the keyboard driver code).

 

Many thanks for help with this.

 

[+mizapf]

Have a look at my text on http://www.ninerpedia.org/index.php/Geneve_keyboard_control

 

The software driver is only one part. The other part is immutable inside the Gate Array. As I see it, this makes it impossible, for example, to adapt the Geneve to AT-style keyboards or even PS2-compatible ones.

[+Ksarul]

Not unless we design a new gate array, which isn't a trivial process. . .

[pnr]

Have a look at my text on http://www.ninerpedia.org/index.php/Geneve_keyboard_control

 

The software driver is only one part. The other part is immutable inside the Gate Array. As I see it, this makes it impossible, for example, to adapt the Geneve to AT-style keyboards or even PS2-compatible ones.

 

Many thanks, that was most helpful. I found the following two links also useful:

http://www.computer-engineering.org/ps2protocol/

and

https://www.cs.cmu.edu/~jmcm/info/key2.txt

 

Taking it all together made me understand how the Geneve keyboard interface works. With hindsight it is a petty they included the shift register. Had they done a software 'bit banging' driver (which really would not have loaded the CPU very much) conversion of the Geneve to AT and PS/2, even USB keyboards would have been feasible by merely upgrading the driver.

 

I might try doing a PS/2 keyboard interface on a breadboard, just to see if it works.