make a parallel keyboard

[Dutchie]

Hi, I am making a keyboard that can be connected with a parallel port on the computer, does anyone have any good links with info ???

 

[kinjalgp]

How many keys do you need?

 

[john1]

Hi Dutchie,

I think the keyboards on some early PCs used RS232,
you might find that would interface easily with the
parallel port.

But you might have to write something to the chips
to make them look at the parallel port instead of
the usual keyboard socket ...

Best of luck with it, John

 

[Exo]

Hi, I am making a keyboard that can be connected with a parallel port on the computer, does anyone have any good links with info ???

Is it supposed to be a full grown keyboard to replace the normal keyboard, or just a extra keypad?

If it's supposed to be a full keyboard then you're going to run into troubles on the software side, native keyboard support is integrated into the bios, so you would have to write your own bios routines and burn them to the pc's flash chip.

 

[Dutchie]

No, i just want like 10 to 15 extra buttons for some commands .... maybe even multiplexed to a digital input for the computer

 

[Exo]

well, 16 buttons can be converted to 4 lines with a binairy priority encoder (search a little in the 74-series), these 4 lines can be connected to the input pins of a parallel port.

Just poll the 4 input lines with software and you're off.

 

[Dutchie]

yes, wel that is not a problem, I already made such a conversion + keyboard, I am looking for info on the interface with the pc

 

[mugzzzzy]

well if u really want to make it parralle....

hi, what i suggest if u really want to have it paralle.... is to use a uart to get the serial code send by the keyboard (8 data bit odd parity one stop bits),the uart will give u a paralle data...but the thing is that the keyboard sends scan code not the ASCII ...so u'll need to decode the scan code and make it ASCII...but if u attend to have only 0-15 extra buttoms.... i sugest u use a keypad with a keypad encode that has a 4x4 matrix

have fun :roll:

 

[pwollner]

there are some other ways of doing that:

if it does not have to be limited to the lpt port you can use the serial port and the attached file

its great; you are not limited to one keyboard but to as many remote controls as you can find

use girder to configure the whole thing
www.girder.nl