Re: Apple ][e mod -- keyboard converter needed

[Michael J. Sch�lke <news0301@mjschuelke.de>]

Rob Gibson wrote:

> I want to do an Apple ][e mod, replacing the contents of the system with a 
> modern PC. 

What a pity... At least, give the innards of the Apple to someone who 
cares.

> The motherboard I am considering uses PS/2 connectors, but I 
> would like to retain the original Apple keyboard.  What would be necessary 
> to convert the scancodes from the Apple ][e keyboard to a PS/2 signal?  

A microcontroller -- a simple PIC 16F8x should do the job. The Apple's 
keyboard outputs parallel ASCII. You'll have to convert the ASCII codes 
to scan codes, then output the scan codes serially according to the PS/2 
protocol. An excellent description of the latter is floating around on 
the web; you should be able to find it through Google.

> Would I need a small PROM, programmed with the conversion table or could I 
> do this in software?  

A conversion table won't be enough -- the PS/2 protocol expects 
keyboards and mice to have some intelligence of their own. Using a 
microcontroller *is* doing it in software ;-) 

It might be possible to hook up the Apple keyboard directly to the PC's 
printer port. You'd have to write your own device driver, though. Doable 
under Linux, near impossible (unless you are *really* skilled in that 
kind of thing) under Windows. 

> Would examining an emulator's source code help in 
> this task?  

Not really. Reading Sather's "Understanding the Apple IIe" would. 

Regards, 
Michael