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IBM XT 5160 keyboards

I'm going to have an XT soon myself. I have a few ps/2-> AT converters, but if I've got the older BIOS (which I think I do) then I might join you in making a signal converter as well! Maybe we'll both be able to try to make one work... of course, I have to really brush up on my electronics.
 
sqpat said:
I'm going to have an XT soon myself. I have a few ps/2-> AT converters, but if I've got the older BIOS (which I think I do) then I might join you in making a signal converter as well! Maybe we'll both be able to try to make one work... of course, I have to really brush up on my electronics.
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Sounds like fun.
 
Terry Yager said:
Without a keyboard?
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Doh. Better go take my pills.

lutiana said:
So the Chip will say either U18 or U19 on it.
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No. All components on the circuit card are given a designation. For example, the crystal is "Y1". You wil find the component designations printed on the circuit board right next to the component.

lutiana said:
Relative to the keyboard jack (ie if it is on the top right) where on the board are these chips?
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With the keyboard jack in top-right corner (and looking at component side of board), U18 and U19 are the chips to the immediate right of the block of switches.
 
modem7 said:
With the keyboard jack in top-right corner (and looking at component side of board), U18 and U19 are the chips to the immediate right of the block of switches.
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U18 = 1501512
U19 = 5000027

So I have the 11/08/82 bios revision and I am not sure what this means exactly. Would a 101-Key Keyboard with an AT/XT switch work with this BIOS?
 
lutiana said:
So I have the 11/08/82 bios revision and I am not sure what this means exactly. Would a 101-Key Keyboard with an AT/XT switch work with this BIOS?
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The 101 keyboard postdates your BIOS.
The answer to your question is, either not at all, or perhaps some the keys that are new to the 101 keyboard would not work. You would be taking a chance.
I seem to remember that there was discussion on this recently (that's pretty good since my pills haven't kicked in yet!)

The 101 keyboard is not officially supported until the next revision of the BIOS, the 01/10/86 revision.
 
lutiana said:
Hmm, interesting idea.

Are there any resources out there on this? I tried to google such a thing, but could only find a way to make an XT keyboard work with an AT system, and obviously I want to go the other, less common, route.
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There are quite a few projects out there using the PS/2 keyboard. Here's an example. Try googling "AVR PC Keyboard" and "PIC PC Keyboard".

AVRs and PICs are very inexpensive to get into and there is a ton of resources available. What makes me think that a project like this would be fairly easy is that (a) there is a lot of existing code to interface to PS/2 keyboards and (b) there's +5 on the keyboard connector to power the thing--the whole affair shouldn't be much more than a lump in the cable.

...and you can make the 5150 owners happy as well.
 
So I have done a little more research and I think such a device would be quite simple to make. The hardest part would be writing the software to translate the AT scan codes to XT ones.

There are quite a few projects out there to convert these codes to some other things (RS-232 being the most common), so it may be as simple as modifying these.

I need to do way more research to come up with a design, and will most likely need help with the actual design.

Stay tuned.
 
So my preliminary research on this is good. I have been talking to a friend of mine that is familiar with ASM coding and he thinks modifying some code out there to output XT scan codes (versus RST-232 or ASCII) should be pretty easy and he is prepared to help.

Once he codes it, we will look at getting the parts and bread boarding a mach up and get some testing going.

I am thinking we can add a switch on the device to be able to set it for 101, 83 or 82 key emulation. In this case the device would simply ignore any extended keys that are pressed, and making it more compatible with the older 5160 or 5150 BIOSes. Any thoughts on this?
 
Lots more research, and I am more and more convinced that I can get this right.

I think that it could also be possible to include a USB to XT option aswell. Theoretically I could have a PS/2 and USB plug on the device and an XT cable on the other end. First I want to get it to work with PS/2 and AT scan codes.

My programmer might be a bit flaky, and I am completely unable to do the programming needed on the PIC (certainly not in assembler).

So is there someone out there that is able to code this? Or is there a higher level language that can be used on the PIC PLCs?
 
There are C compilers available for both PIC and AVR.

But if you want to use the minimum amount of hardware possible, assembly coding is a must. You might even be able to fit the whole thing (sans USB functionality) into a single PIC12F629 8-pin DIP.
 
I am going to use a PIC16F84-04/P 18Pin controller.

I will look up the one you mentioned, if I can code it in C I think I might be able to do it. I just have to learn C first :D
 
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