Search found 76 matches

by MMcM
Yesterday, 04:14
Forum: Workshop
Topic: Need help on a Tandy TRS-80 USB conversion
Replies: 8
Views: 578

Re: Need help on a Tandy TRS-80 USB conversion

MMcM wrote:
11 May 2020, 06:10
This initial version doesn't seem 100% reliable, unfortunately.
It's much more reliable after turning off the SOF interrupt on hasu's advice. I won't promise 100%, but it should definitely be usable now.
by MMcM
Yesterday, 04:07
Forum: Workshop
Topic: HP-HIL
Replies: 7
Views: 402

Re: HP-HIL

As for parity error, it seems that ISR(INT0_vect) is interfered by 'USB SOF' event and fails to track signal. After disable the event I don't see the error. Thank you very much for this. I have incorporated your patch into my branch, putting it under a conditional for Lufa's existing NO_SOF_EVENTS ...
by MMcM
28 May 2020, 15:50
Forum: Gallery
Topic: Space Cadet PCB? - SD16273
Replies: 10
Views: 517

Re: Space Cadet PCB? - SD16273

So it seems that 103S could refer to 103SD24-2 or 103SD30-? Yeah, and maybe other models that we haven't found yet. I've always assumed that it was <number of keys><switch type><category number>-<sequential number>, without any firm basis. I have 5, 24, and 30 for the first. And 1, 2, 3, and 5 for ...
by MMcM
28 May 2020, 15:21
Forum: Workshop
Topic: Epson Q703D-AA conversion
Replies: 29
Views: 497

Re: Epson Q703D-AA conversion

MMcM, I have a light hearted question if it doesn't offend you. mcmaxmcmc and I have met in real life, a million years ago when meetups were possible. DMA was there, too. MMcM is just initials, as you surmised. Full name isn't really like a secret: you could find it in RFC 742. MMCM is 2900 in Roma...
by MMcM
28 May 2020, 01:42
Forum: Keyboards
Topic: AEK II and tmk_keyboard - how to the keep Numlock LED on?
Replies: 2
Views: 147

Re: AEK II and tmk_keyboard - how to the keep Numlock LED on?

At the end of that same file, modify led_set itself to or in bit 1 before calling adb_host_kbd_led.
by MMcM
28 May 2020, 00:01
Forum: Gallery
Topic: Space Cadet PCB? - SD16273
Replies: 10
Views: 517

Re: Space Cadet PCB? - SD16273

That is a great find. It's been a very long time, but I seem to remember that the PCB already existed. From JLK's original notes: Using a Microswitch 103S keyboard. Again, I'm not 100% sure what this refers to; I guess we could see if John remembers. But my guess is a 103SD30-n to go with 108SD30-1 ...
by MMcM
26 May 2020, 07:01
Forum: Workshop
Topic: Epson Q703D-AA conversion
Replies: 29
Views: 497

Re: Epson Q703D-AA conversion

Second question is that I assume a logic analyzer will be handy and I'm wondering whether I could use this $13 from amazon? along with pulseview? There's a customer review there that says it works well with it. And it sure looks like all the other clones. What does "usually because of not evough mo...
by MMcM
26 May 2020, 06:27
Forum: Keyboards
Topic: RS232 to USB?
Replies: 3
Views: 185

Re: RS232 to USB?

Very nice. I see that there is another BCRU211G-001 for sale on eBay right now. You should be able to connect the terminal's RS232 port to USB on a Linux machine and do shell stuff. Just search eBay / Amazon for USB to DB25 Serial. Most of these will sell you an FTDI (or clone) to DB9 and then a DB9...
by MMcM
26 May 2020, 04:15
Forum: Workshop
Topic: Reviving a Unitek K-150M (K-151?) XT keyboard
Replies: 12
Views: 447

Re: Reviving a Unitek K-150M (K-151?) XT keyboard

Got it. Sorry for misreading what you said earlier.

If RESET being asserted all the time has been ruled out, then I guess, yes, wait and see how a new MCU does.
by MMcM
26 May 2020, 04:13
Forum: Keyboards
Topic: RS232 to USB?
Replies: 3
Views: 185

Re: RS232 to USB?

Real RS-232, with voltages up to like ±15 V? Or TTL level serial with the RS232 bit encoding? Most keyboards would have the latter. Full-blown terminals would have the former. For TTL serial to USB, there are standard chips like FTDI https://www.adafruit.com/product/70 or https://www.sparkfun.com/pr...
by MMcM
25 May 2020, 19:41
Forum: Workshop
Topic: Reviving a Unitek K-150M (K-151?) XT keyboard
Replies: 12
Views: 447

Re: Reviving a Unitek K-150M (K-151?) XT keyboard

Oh, this is encouraging. Please do post the binary file and/or disassembly someplace. (Some kinds of attachments are allowed here, but perhaps not those.) 4 is a strange place to be fetching all the time, so trying a replacement MCU seems like a solid idea. When reset, the program starts at 0, where...
by MMcM
25 May 2020, 18:01
Forum: Workshop
Topic: HP-HIL
Replies: 7
Views: 402

Re: HP-HIL

Okay. Had a closer look at the photos of 46081A Bitsavers to try to confirm for myself what it does. I had been parsing "HP-HIL / Audio Extension" all wrong. It isn't an Audio Extension. It's an HIL extension with audio thrown in. That is, it is a TTL repeater with an 8 Ohm speaker in the same box, ...
by MMcM
25 May 2020, 04:54
Forum: Keyboards
Topic: Weird HP keypad with 32 keys
Replies: 6
Views: 1017

Re: Weird HP keypad with 32 keys

by MMcM
25 May 2020, 04:44
Forum: Workshop
Topic: HP-HIL
Replies: 7
Views: 402

HP-HIL

For a change, I decided that rather than reverse engineering something that would ultimately turn out to be a simple protocol with funny voltages, I would have a go at something well documented but complicated: HP-HIL . This is a multi-device protocol, so like USB. But in a daisy-chain, so even more...
by MMcM
23 May 2020, 01:56
Forum: Workshop
Topic: Terminal Keyboard with Hi-Tek grid and NS SKI
Replies: 1
Views: 135

Terminal Keyboard with Hi-Tek grid and NS SKI

I picked up this little terminal keyboard because it had the look of being from before everything was standardized or so probably with something interesting going on. bridge-case-top.jpg The case is all metal: the top is aluminum and the bottom is steel. bridge-case-bottom.jpg It wasn't a total surp...
by MMcM
22 May 2020, 15:34
Forum: Workshop
Topic: Reviving a Unitek K-150M (K-151?) XT keyboard
Replies: 12
Views: 447

Re: Reviving a Unitek K-150M (K-151?) XT keyboard

The LEDs come up and stay on, right? I imagine they are active low and that will be the power-on state of those ports on the MCU. But it might be worth checking that, since if it has to drive them high, it might be alive. I imagine any 8039 will do, ignoring the manufacturer and process details. You...
by MMcM
22 May 2020, 04:34
Forum: Other external
Topic: Great/Interesting Finds
Replies: 23347
Views: 1589936

Re: Great/Interesting Finds

by MMcM
17 May 2020, 06:28
Forum: Other external
Topic: Great/Interesting Finds
Replies: 23347
Views: 1589936

Re: Great/Interesting Finds

Early Licon (Cortron / ITW):

https://www.ebay.com/itm/164203870608

Pretty sure this is from a Vydec word processor.
by MMcM
15 May 2020, 02:28
Forum: Other external
Topic: Great/Interesting Finds
Replies: 23347
Views: 1589936

Re: Great/Interesting Finds

Two revs of ITW/Cortron 80-551646: Rev A: https://www.ebay.com/itm/392797912706, the dark one. Rev C: https://www.ebay.com/itm/193449295181, the light one. The first looks to have five replacement keycaps, but they otherwise match. This layout has two ! legends! One on a key with four legends, so I ...
by MMcM
11 May 2020, 21:40
Forum: Workshop
Topic: Need help on a Tandy TRS-80 USB conversion
Replies: 8
Views: 578

Re: Need help on a Tandy TRS-80 USB conversion

Yes, as an earlier post from that same blog, http://nerdlypleasures.blogspot.com/2016/08/the-northgate-omnikey-to-tandy-1000.html, points out, the Tandy scan codes are clearly taken from the 83-key XT ones. This is apparent looking at the spec. Of course, with 90 keys, something has to be done about...
by MMcM
11 May 2020, 06:10
Forum: Workshop
Topic: Need help on a Tandy TRS-80 USB conversion
Replies: 8
Views: 578

Re: Need help on a Tandy TRS-80 USB conversion

I spent a little bit of time looking into what might be possible without a controller replacement. I too only have access to a Tandy 1000 keyboard, though it looks pretty much the same except for having a DIN-8 instead of a DIN-5. It might even be the same PCB. tandy-1000-top.jpg tandy-1000-bottom.j...
by MMcM
08 May 2020, 18:00
Forum: Keyboards
Topic: IDENTIFY THE KEYBOARD thread
Replies: 4170
Views: 304936

Re: IDENTIFY THE KEYBOARD thread

I bought these keycaps about a year ago on ebay. Does anybody by any chance know which keyboard they originally belonged to? It's obviously Micro Switch, but that's as far as I got. The System 10 had CTL for the F keys. https://archive.org/details/bitsavers_singersystnModel82DisplayApr75_1401913/pa...
by MMcM
04 May 2020, 04:57
Forum: Other external
Topic: Great/Interesting Finds
Replies: 23347
Views: 1589936

Re: Great/Interesting Finds

dcopellino wrote:
03 May 2020, 15:14
Radio shack keyboard 277-1020 replacement.
I believe these were surplus Coleco Adam keyboard insides. If so, they are (better than average) rubber domes.
by MMcM
04 May 2020, 00:49
Forum: Workshop
Topic: Man vs MicroSwitch: Converting a SD16234
Replies: 38
Views: 3442

Re: Man vs MicroSwitch: Converting a SD16234

There is an eBay seller who seems to have a bunch of these SD-16234 boards for sale. Specifically, as 99SD24-3. There are a couple listings up now. They look very similar to LessthanZero's board, except that a couple of the keys (Bell Off and Tab) are white. They come with a light-pen, which is perh...
by MMcM
02 May 2020, 19:11
Forum: Other external
Topic: Great/Interesting Finds
Replies: 23347
Views: 1589936

Re: Great/Interesting Finds

A Wyse terminal: https://www.ebay.com/itm/143558714664 Interesting for a couple of reasons. One, not only does it come with the original box. But the original box is addressed to Thinking Machines. From where over 35 years it made it to a thrift store in Danbury. Second, the keyboard, in all its ste...
by MMcM
20 Apr 2020, 16:26
Forum: Workshop
Topic: Need help on a Tandy TRS-80 USB conversion
Replies: 8
Views: 578

Re: Need help on a Tandy TRS-80 USB conversion

Here is the Service Manual for the Tandy 2000, which I believe is that specific model: http://bitsavers.org/pdf/tandy/26-5103_4_Tandy_2000_Service_Manual_1984.pdf. See section 7.6. The protocol looks to be the same as the Model II, discussed on the EEVblog: https://www.eevblog.com/forum/beginners/in...
by MMcM
18 Apr 2020, 23:18
Forum: Keyboards
Topic: How to figure out a keyboard protocol
Replies: 12
Views: 581

Re: How to figure out a keyboard protocol

Yeah, that photo is fine. Some of the earlier analysis was upside down. mai-4313.jpg Pin 3 of the connector goes to a pull-up resistor (R6) and then to pin 1 of the inverter. Pins 2 and 3 are shorted -- you can just make out the trace in the photo. This is the same trick as in the 4309. Then pin 4 g...
by MMcM
18 Apr 2020, 19:59
Forum: Keyboards
Topic: How to figure out a keyboard protocol
Replies: 12
Views: 581

Re: How to figure out a keyboard protocol

Okay, yeah, two inputs and no outputs doesn't sound right. There aren't any other unaccounted for signals on the connector, right? I've made mistakes like that before. The thing to do is gather more evidence, analyze the contradictions and figure out where it went wrong. It's possible that the data ...
by MMcM
18 Apr 2020, 01:04
Forum: Keyboards
Topic: How to figure out a keyboard protocol
Replies: 12
Views: 581

Re: How to figure out a keyboard protocol

MB74LS14 or MB74LOS14? MB is the manufacturer, specifically Fujitsu. Have a look at https://en.wikipedia.org/wiki/7400-series_integrated_circuits#Part_numbering. In short, stuff at the beginning and stuff at the end doesn't matter for figuring out what it does. A 74LS14 is a 6-way (hex) inverter (wi...
by MMcM
17 Apr 2020, 23:30
Forum: Keyboards
Topic: How to figure out a keyboard protocol
Replies: 12
Views: 581

Re: How to figure out a keyboard protocol

To start, I would bet that the protocol is going to turn out to be ASCII with the special keys sending funny codes. So making this into a working modern keyboard would mean scanning yourself. Of course, I could be dead wrong. There are a couple of other Mai terminals in Bitsavers. The 4398 , which h...

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