FPGA Central

Hi,

I want to make a custom PS/2 keyboard.

I have a Xilinx SpartanII part on my custom keyboard and I am
looking to implement a PS/2 keyboard interface so that I can
plug my custom keyboard into a standard PC PS/2 port.

Googling for an opencore has so far been fruitless.

I've tried opencores.org, but they only have a PS/2 keyboard interface
that would be implemented on the host side (not keyboard side).

Verilog is my preferred HDL.

Thanks for any help,
Jason.

On Thu, 5 Feb 2004 05:50:58 -0800, "Antti Lukats" <[email protected]>
wrote:

>"Jason Crawford" <[email protected]> wrote in message
>news:1075949641.602326@sj-nntpcache-3...
>> Hi,
>>
>> I want to make a custom PS/2 keyboard.
>>
>> I have a Xilinx SpartanII part on my custom keyboard and I am
>> looking to implement a PS/2 keyboard interface so that I can
>> plug my custom keyboard into a standard PC PS/2 port.
>>
>> Googling for an opencore has so far been fruitless.
>
>there is possible no keyboard side core available as it is not a very comman
>thing to have

It's also not commonly done in an FPGA.
Most PS/2 keyboards use a mask programmed 8048, although I did once
find one (from Fujitsu) that used a mask programmed 6805.

If you really must use an FPGA, you could probably write the code in a
few minutes, once you find a reference to the protocol
... googling ...
http://govschl.ndsu.nodak.edu/~achap...ro/PS2/ps2.htm
or
http://www.networktechinc.com/ps2-prots.html
http://www.networktechinc.com/technote.html

Regards,
Allan.

Jason Crawford <[email protected]> wrote in message news:<1075949641.602326@sj-nntpcache-3>...

> I have a Xilinx SpartanII part on my custom keyboard and I am
> looking to implement a PS/2 keyboard interface so that I can
> plug my custom keyboard into a standard PC PS/2 port.
>
> Googling for an opencore has so far been fruitless.
>
> I've tried opencores.org, but they only have a PS/2 keyboard interface
> that would be implemented on the host side (not keyboard side).

Build one yourself.
To receive the codes is more complicated then sending them and in a
lab course I teach it takes my students about four hours to build a
PS2 receiver.
So a sender should be no problem.

The protocol is described here:
http://govschl.ndsu.nodak.edu/%7Each...ro/PS2/ps2.htm

The scancodes are here
http://govschl.ndsu.nodak.edu/%7Each...cancodes2.html

For most keys you just have to shift out one byte when the key is
pressed and two bytes when it is released.

I expect that interpreting whatever it is that you use for your keys
is a lot more complicated then the PS2 part which I estimate at 10
lines VHDL at most.
(Plus any FIFOs that you might want to add)

Kolja Sulimma

"Jason Crawford" <[email protected]> wrote in message
news:1075949641.602326@sj-nntpcache-3...
> Hi,
>
> I want to make a custom PS/2 keyboard.
>
> I have a Xilinx SpartanII part on my custom keyboard and I am
> looking to implement a PS/2 keyboard interface so that I can
> plug my custom keyboard into a standard PC PS/2 port.
>
> Googling for an opencore has so far been fruitless.

there is possible no keyboard side core available as it is not a very comman
thing to have

I would personally probably do it a little tweaking, putting a PicoBlaze
processor onto the FPGA
it takes one Block RAM and about 70 Slices. It does fit into any spartan. So
you can use it
even in XC2S15. Even though a simple PS2 SIE (serial interface engine)
itself is smaller than
PicoBlaze then if you add full keyboard control status leds etc.. I think
you will end up in similar
Slice count or more.

antti