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Turbo XT woes

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Reply 20 of 33, by FAMICOMASTER

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Horun wrote:

Good job FAMICOMASTER ! Think I would stick with the original BIOS until you get the KB thing figured out.

Thanks! Both BIOSes came out of the same kind of board - Both were DTK Turbo 640s.
One just happens to be a Phoenix BIOS (original to this specific board) and one happens to be a Turbo XT BIOS (which came from my parts board).

I think I like the Turbo XT BIOS better, since the Phoenix BIOS makes the cursor look weird in DOS and because it will show some of the configuration on boot.

One of these days I'll find someone to loan me an EPROM programmer for a weekend to work on getting a better BIOS for it - Until then I think between the two chips it should be a-okay.

Anonymous Coward wrote:

In my experience, the model Ms don't really work properly on XT computers. I had the same problem with my turbo XT board...the keyboard worked intermittently. I ended up having to use an AT to XT keyboard converter to get it working properly.

There is a special model M for XT computers that doesn't have LEDs. It was sold with a later XT motherboard that had a BIOS that supported the extra keys. Not sure if that particular keyboard works on normal XTs, or if that motherboard supports regular model Ms, but maybe both are required to work.

Damn. This keyboard works flawlessly with every other machine I have, excluding one cheap eMachines which has some wonky USB to PS/2 adapter.

Was kinda hoping to find a way to get this keyboard to work for now so I don't have to go all the way to my parent's house (Where I store a lot of my computer stuff while I'm living in this apartment), which is a good 4 hour drive one way...

Maybe I'll see if they can mail the Model F to me, that should work with an XT, right? the F1-F10 keys are arranged vertically on the left, I think I got it from a yard sale or something. It may or may not be in pieces.
If it turns out a model F should work, I'll talk to them about getting it down here, I need the face plate for my ST-251 anyways.

Reply 21 of 33, by Caluser2000

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FAMICOMASTER wrote:

.The problem with one of those adapters is that not only is it out of stock, .

Received an email from JD. The PS/2-XT adapters should be back in stock in a week or so. So it may be worth while giving MonoTech PC an email if you are interested in getting one.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 22 of 33, by Anonymous Coward

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I bought a home brew keyboard adapter from somebody on vcfed. Not sure if it's still in production, but doesn't hurt to ask. I don't think it was very expensive.

There shouldn't be any issues with the model F, as long as it's the XT version and not he 84-key AT version.

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Reply 23 of 33, by FAMICOMASTER

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Anonymous Coward wrote:

I bought a home brew keyboard adapter from somebody on vcfed. Not sure if it's still in production, but doesn't hurt to ask. I don't think it was very expensive.

There shouldn't be any issues with the model F, as long as it's the XT version and not he 84-key AT version.

Well, it never worked with any of my AT machines. Ever. I had no idea why initially, I got it before I knew there were different scan codes.

Is there any way to do the translation in software? I don't need it during BIOS, just afterwards in DOS - Is there a TSR that will make the scancodes sensible to MS-DOS?

Reply 24 of 33, by HanJammer

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FAMICOMASTER wrote:
Anonymous Coward wrote:

I bought a home brew keyboard adapter from somebody on vcfed. Not sure if it's still in production, but doesn't hurt to ask. I don't think it was very expensive.

There shouldn't be any issues with the model F, as long as it's the XT version and not he 84-key AT version.

Well, it never worked with any of my AT machines. Ever. I had no idea why initially, I got it before I knew there were different scan codes.

Is there any way to do the translation in software? I don't need it during BIOS, just afterwards in DOS - Is there a TSR that will make the scancodes sensible to MS-DOS?

No, AT and XT protocols are different and keyboard support is done by MCS-48 series microcontrollers on the motherboard and in the keyboard running their own software (which is not really something you can change using any software running in the OS layer). It would require reprogramming both controllers (one on the motherboard and one in the keyboard - I doubt anybody did that) which is not really a good idea. So you need a hardware component which will do translation on the fly between the keyboard and motherboard - there is no need for(overpriced) specialized AT-XT keyboard adapter - you can buy the cheapest Arduino compatible board, DIN5 plug and DIN5 socket, hook them up to Arduino, load this software: https://github.com/kesrut/pcxtkbd/ and you are good to go. Can't be cheaper and easier than that. -> https://www.youtube.com/watch?v=HJOUtIbPJsg

Also Super Turbo XT BIOS I mentioned earlier has solid support for Enhanced 101 key keyboards (still keyboard has to support XT protocol) in case you need it for some reason.

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Reply 25 of 33, by FAMICOMASTER

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Agh, that sucks. I suppose I'll just get my model F and hope it works right.

Reply 26 of 33, by Horun

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Hmm you don't have an old AT style KB that has the nice XT/AT switch on back laying around ? They work great for testing purposes.
BTW picked up a Leading Edge DC-2014 xt KB for $5 at a thrift store a few months ago, was very clean and works great, not as nice as a model F but am not complaining 🤣

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 27 of 33, by FAMICOMASTER

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Horun wrote:

Hmm you don't have an old AT style KB that has the nice XT/AT switch on back laying around ? They work great for testing purposes.
BTW picked up a Leading Edge DC-2014 xt KB for $5 at a thrift store a few months ago, was very clean and works great, not as nice as a model F but am not complaining 🤣

I only have three keyboards with the 5-pin DIN connector total.
IBM Model F, an SIIG Suntouch Jr, and a generic AST keyboard which has a slew of bad switches. The SIIG and AST work in AT class machines and neither have a switch anywhere.

I don't usually buy keyboards - Either I use the ones I have (by themselves or with an adapter), or they come with the machine.

No keyboard came with this machine.

Reply 28 of 33, by FAMICOMASTER

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Damn, just found out my IBM Model F says "IBM Personal Computer AT" on the badge. Any chance it will still work with the XT, or am I going to have to get a different keyboard? If so, any recommendations for a good, cheap model? I'd rather not use an adapter.

If I pull the keyboard microcontroller from a dead IBM 5170 motherboard, do you think it would work properly in an XT board?

Reply 29 of 33, by Horun

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Cheapest decent XT KB I could find: https://www.ebay.com/itm/Vintage-Fujitsu-FKB4 … U4AAOSwZNtb~d0D
I would verify it is XT not AT before buying...

I think HanJammer could probably answer this better but think if the inputting an AT keyboard scan into an XT and have a XT rescan the KB input thru a XT KB controller, it will not work.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 30 of 33, by HanJammer

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Horun wrote:

I think HanJammer could probably answer this better but think if the inputting an AT keyboard scan into an XT and have a XT rescan the KB input thru a XT KB controller, it will not work.

Well, if it would be as easy as putting 8042 (AT KBC) in place of 8046 (XT KBC) and connecting AT keyboard then this would be extremally popular thing to do (a common knowledge) and people simply wouldn't pay 40+ USD for XT keyboards or look for alternatives like creating hardware adapters because 8042 and compatible KBCs are still readly available. Yet nobody does that and I guess there is a reason. It's not only that AT and XT keyboard protocols are different - there is also a problem with scan codes passed by keyboard controller which are different as well and BIOS needs to know how to interpret these scan codes. So short answer is no - simply switching the KBC from AT motherboard to XT motherboard won't do the trick. I'm not an expert, but I guess that even if the XT BIOS would be able to interpret AT scan codes, and even after replacing 8046 with 8042 (which has pretty much the same pinout) there still could be issues.

Also this is a good read http://www.hth.com/filelibrary/TXTFILES/keyboard.txt

PS: 40$ for this Fujitsu keyboard is a decent price if it's AT/XT.

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Reply 31 of 33, by FAMICOMASTER

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There's no AT/XT switch and I don't know how to tell if it's truly an XT keyboard.

How much are the scan code converters?

To put what I'm asking in different words...
What is the absolute cheapest possible way to use a keyboard on this machine? Pennies count here.

Reply 32 of 33, by HanJammer

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FAMICOMASTER wrote:

There's no AT/XT switch and I don't know how to tell if it's truly an XT keyboard.

Google it.
This is very good reference: https://deskthority.net/ and another one is: https://geekhack.org/

Some keyboards are XT/AT autosensing and they will have no switch (but usually will have something like "XT/AT Autosense" stated on the sticker).

FAMICOMASTER wrote:

How much are the scan code converters?

To put what I'm asking in different words...
What is the absolute cheapest possible way to use a keyboard on this machine? Pennies count here.

There are dedicated AT2XT converters like this one: https://monotech.fwscart.com/PS2_to_XT_Keyboa … 4_19714002.aspx but prices start at 25 USD. Cheapest possible is 1-2 USD Arduino Nano https://www.ebay.com/itm/For-Arduino-5V-16MHz … P8AAOSwZfRdb1m8 and 5 USD DIN5 extension cable (https://www.ebay.com/itm/6-25Ft-DIN5-DIN-5-Pi … -59D89GG8TxeP0w) or male and female DIN5 plugs - all what you need to build converter yourself (I linked instructions and code in previous posts).

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Reply 33 of 33, by FAMICOMASTER

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I'll probably end up with the Monotech. I've got a couple Arduinos already, but I'm really not interested in using them for this.

Thank's much for the advice!