Re: parkbd adapter

[Vojtech Pavlik <vojtech@suse.cz>]

On Wed, Jan 21, 2004 at 09:22:34AM -0200, Evaldo Gardenali wrote:

> I *KNOW* how to google...
> I actually just needeed *DOCUMENTATION* I can't find anywhere, and the
> author seems to ignore my mails (or it goes to spam trash, or whatever
> happens, the thing is I don't get a reply)
> I wonder how useful is a piece of code present in millions of boxes if
> virtually NOBODY knows how to use it. and it annoys me a bit that many
> requested features are out of the kernel, but a feature that is in the
> main tree is virtually useless (if its really useful, where's the link
> for the docs?)
> </rant>
> sorry, but I feel frustrated with that

Your mail is still hanging in my inbox, and unfortunately I don't have
the complete schematic for the parkbd adapter anywhere near me.

I was hoping I could find it, but I suppose the following might be
enough for you to build the adapter:

It's really simple, just two diodes and two resistors in this
arrangement:

            ______
+5V -------|______|--.
                     |
INPUT PIN -----------|
		     |--- KBD PIN
OUTPUT PIN ---|<|----'

Now for KBD CLOCK you use STROBE and ACK pins on the parallel port and
for KBD DATA you use AUTOFD and BUSY pins on the parallel port. I don't
remember the value of the resistor used, but something like 5k should
work OK. It's not completely necessary anyway.

And then you'll also have to connect the keyboard +5V and GND pins. For
+5V you can either use the real keyboard or mouse connectors, get +5V
from the joystick connector or from an external power supply.

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR