PS/2 to PCjr Keyboard Converter - Schematic and Source

Hardware questions and modifications

Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Sun May 10, 2015 8:25 pm

OH! I see. It's when Num Lock is on, they function just like the keys on the number pad, so holding SHIFT down does things like making 7 Home and 1 End. That might be a bit of a perplexing problem to solve since it's essentially the system's interpretation of the key presses that's doing that. I mean, essentially the solution would have to be to have the microcontroller check the Num Lock flag and send out a Num Lock make/break before and after each number key stroke when it's active.
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Sun May 10, 2015 8:58 pm

So, I just implemented the solution I listed above (it's actually very simple to put in compared to how I thought it would be) and it works unless the PCjr misses one of the NumLock key strokes. Then everything's haywire until you reboot the computer.
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Sun May 10, 2015 9:15 pm

Okay, in order to improve things a bit, I decreased the bit cell timing just a tad and increased the number of stop bit cells the microcontroller sends out at the end of each scan code. Things seem to be much more reliable now, at least on my end.

I don't have the new sources committed yet, but if anyone wants to text the fix out, here is a link to the hex file. You should be able to upload it directly to the PIC using whatever programmer you have:

http://mkgraham.dx.am/PS2PCjr_12F617_NumlockFix.hex
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jharre » Sun May 10, 2015 9:20 pm

jmetal88 wrote:OH! I see. It's when Num Lock is on


Ah, exactly! I did have the Num Lock on. I was about to drag out another jr to see if it was only this machine, but you fixed it before I could do that. You da man!
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Sun May 10, 2015 9:32 pm

I gotta say, I'm surprised by the amount of stability increase I got from increasing the number of stop bit cells. Decreasing the bit cell timing always seemed to help marginally up to a point, and now I see why it was only up to a point. Decreasing it to the point where the PCjr could reliably read each bit wasn't giving enough time between scan codes for the PCjr to do its processing on everything, so adding more stop bit cells actually helped dramatically. Let me know how things go when you flash the hex file! The reason I was reluctant to change the timing so much originally was because I was afraid my PCjr's keyboard timing might be off compared to others', but if it doesn't negatively affect your experience, I'll make this timing the new default.
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby James » Mon May 11, 2015 10:05 am

Hooked up the keyboard adapter and other than the numlock problem, it has been working flawlessly. I am using an old Compaq, circa 1990s, keyboard. It is better than my typing skills allow. It seems to be completely compatible with the PCE keyboard buffer routines. It even works with the now redundant lights on the PCE Configuration Plus cartridge.
-PCjr (1989)-DOS 3.3, Racore Drive II, jrIDE-128 MB DOM, jrExcellerator, Tandy Mod, Serial Card, Combo v2, Config Plus, IBM Parallel Port, Megaboard, Xircom PE3-10BT
-PCjr (2001)-DOS 3.3, jrIDE-128 MB DOM, NEC v20, Parallel Port, Comswap, Xircom PE3-10BT
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Tue May 26, 2015 2:06 pm

Just so everyone knows, I'm looking at possibly moving soon to accept a job at a company that's about a 3-hour drive away. It might be a little premature, but I've begun trying to pack the apartment up already so I can be ready to leave as soon as possible when the time comes. As a result, the four units I have left (again, two 'iffy' units and two 'solid' units) will probably remain packed until after the move, thus they will be unavailable for sale for a while.
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jharre » Tue May 26, 2015 9:24 pm

Good luck with the job! The first job out of school is kind of exciting.

A thought for the future if you do another run of boards - a couple mounting holes in the board would be handy. Looks like there is space. I plan to put mine in a small plastic box and think I've found a couple likely spots to drill. This IS a two layer board, right?

Anybody have software for a K150 style PIC USB programmer that programs this chip (a 12F617)? Though my programmer came from LA, apparently that's just a mailing point and the shop owner is in China. Their "support" consists of sending me to various Chinese web sites in search of software. My knowledge of Chinese is non-existent, so I haven't had much luck getting it going with this particular PIC part. :(
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Thu May 28, 2015 11:19 am

Thanks! Turns out they found someone more qualified for the position I had applied for, but they called me back to interview for a different position. I feel like the second interview didn't go so well, though, so I'm not so confident I'll be moving soon after all. But I guess we'll see. It sounded like they only had one other candidate for this other position, so either the other guy does better and he gets the job or he does worse and I get the job.
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Re: PS/2 to PCjr Keyboard Converter - Schematic and Source

Postby jmetal88 » Sun Jun 28, 2015 12:03 pm

I kind of forgot to come back to this thread after that last post... I did get the job. I am working as a bench test technician in their quality department now. I am 100% moved out of the old apartment, so all the parts and whatnot are here, but I don't have a whole lot actually unpacked yet. If someone wants to order one now, though, I can go look for them.
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