[WTB: Strike Three! for the TI-99/4a]

Still looking? There are two on ebay at the moment. 
 

https://www.ebay.com/itm/285460008407

 

https://www.ebay.com/itm/296377248801

 

Edit I see you got one. Nevermind! 

 

[Question for all you Hardware Guru's]

Let me plug @JasonACT's Pico PEB.  Full thread here: 

Here's my summary of the feature set:

 

- Speech Synthesizer implementation
- 32KB / SAMS / Myarc Foundation Memory
- GRAM/GROM Cartridge + Multi-bank RAM/ROM + MiniMem-RAM
- USB subsystem keyboard + joystick + mouse
- Disk image (.dsk) + TI Files (on SD) support
- Network clock
- RS232 - Via Pico's free Serial2 port
- P-Code Card implementation
- And more... see the file "PPEB2.ino" in the Pico PEB download zip for more details

 

The Pico PEB features are controlled/ enabled via a configuration file as well as TI BASIC commands. 

 

Currently this is a DIY project, so nobody is selling these.  You have to build one (or have someone build it for you).  There is probably a handful of users (4 including Jason, that I know of).

 

Edit Here's a picture of one that I built, it plugs into the TI's side expansion port:

 

 

[TI Related -- Ebay / Heads Up Notice]

Silver side port. If I didn’t already have a QI, I’d take a chance on it. $30 shipped isn’t too bad if it boots.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

10 minutes ago, JasonACT said:

I was wondering what everyone else who has made a Pico PEB has?

Silver & Black: LTA5282

Beige: LTA3983

QI: LTA4383

[Pascal on the 99/4A]

1 hour ago, Tursi said:

we had someone build a top-end AMS tester a few years ago. Does it handle more than 1MB? If yes, what was its approach?

 

I know nothing about implementation, but JediMatt's RAM tester sees greater than 1MB on Classic99, as well as JasonAct's PicoPEB:

 

 

According to the github, the tester will see up to 16MB: https://github.com/jedimatt42/ti994a-memtest

 

[Backbit 32K doesn't work with speech synthesizer?]

I don’t know anything about your RAM expansion, just taking a guess. Did you try plugging in the Ram first, and then speech synthesizer into the Ram?

 

Does the Ram expansion require an external power supply?

[QI model schematics]

4 hours ago, Gary from OPA said:

oh'well.. i guess I can't update the AVR on my FG99

Try a different, preferably non-QI console?

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

Ok, I did the QI mods:

1. Pulled out the resistor pack

2. Pulled out U32 and put in a "shunt" connecting the data lines

 

 

The QI is now able to run carts from the PicoPEB (previously it didn't work):

I am currently running a SAMS burn-in test.

 

I also tested the FinalGrom99 (without the Pico attached) - it doesn't work with Ralph's 1.3 firmware.  It still needs the QI specific firmware to work correctly.

 

Let me know @JasonACT if you would like to see any other testing.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

I would be inclined to touch up the pins on the sd card socket as well. 

[restoring the keyboard]

9 hours ago, PasadenaBrad said:

I really am interested in your Atari experience.

I actually don't have any, other than playing friends' 2600s and 5200s.  The video I link was for an Atari machine, but the keyboard was made by Mitsumi. It appears to have the same mylar design as our TI keyboard, and therefore I thought it might be useful to try the same fix.

[Trying to trace my TI origins...]

A history of Texas Instruments (the company) - price wars at about 33:20

[restoring the keyboard]

Nice writeup, Brad!

 

I recently had a go at this as well, and did not have the success you did.  I did not do everything that you did, so I will go back and try it when I get some time.

 

When I received my keyboard, only one key worked.  Now, most of the keys work but there are few that do not.  Of the ones that do work, there are many that need debouncing.  That is, when I press a key once, I get 4 - 5 characters on screen.

 

My research found a lot of the same fixes as described in your post, but I did find one other possible fix.

 

1. Max's video, which heats the mylar with a heatgun.  I tried this but it had no effect for me.

2. Cleaning the carbon pads with alcohol.  I did this and it certainly improved things for me.

3. Fixing the traces on the keyboard and mylar.  I did not do this, but will go back and do so.

4. Making the keys stiffer, using some heat shrink.  I tried this but don't have the right sized heat shrink, and gave up on it.  Here's the video:

 

 

I think that over time, a lot of things can degrade on this model keyboard.  Each keyboard may have its unique failure points; so a particular fix for one keyboard might not resolve issues with a different keyboard.

 

 

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

11 hours ago, JasonACT said:

a mod that may make it work like an original model

Just curious, can you explain a little more? Does the mod make the side port and the cartridge port behave like the original?  Do you see any other potential behavior changes?

 

11 hours ago, JasonACT said:

I don't want anyone breaking their QI model TI

When I do this, I'd like to do it non-destructively.  My thought was to socket both the resistor pack and U32.  For connecting the blue lines in your image, I was planning on doing that with another socket, which could be removed when needed. That way I can have the non-QI behavior by removing the components and inserting this connector socket; or, if I need the QI behavior I can re-insert the original components.  By doing this there is not a need to cut W7.  Does my theory hold up?

 

I am a little short on time at the moment, but hope to get to it in the 2nd half of April.  Anyone else is certainly free to give it a try.

[Another Youtube Video]

 

I just watched this, it was more a history of TI (the company) than it was about the computer.

[The Joel Test for Software Development]

Decent read. a lot of great points in the article.

 

I found it interesting though that he says developers shouldn't bother each other because it is a productivity downer; however later he says they should run their UIs by others.  I don't know, maybe he's saying it's ok to bother people in the hall ("hallway usability testing"), but not at their desks? Anyway, just questioning out loud... probably only "Joel" can answer that one.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

1 hour ago, JasonACT said:

There'll be no more changes to the new V3 board unless there's a problem, I promise.

I was of course just joking about having an obsolete board. Change is normal and expected, so don’t worry about it too much.

 

Now I need to explore the features on the boards that I have. I’m super excited about it. Thanks again.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

On 2/3/2024 at 6:35 PM, JasonACT said:

I'm extremely reluctant to post this, I have not had circuit boards made from these files, so the files are completely "unverified".  But here are the DipTrace and generated Gerber files with R4 moved and re-purposed from a 10K ohm pull-up to the 470 ohm current-limiter for the SD clock.  I really hope the files have no issues.

Finally got mine built yesterday, and now it's obsolete 🙂.  I put the latest 266mhz 2MB firmware on it.  The SAMS burn-in ran 3 times on one of my TIs, so this PCB works.

 

I might bodge this particular build in the future for the 8MB SAMS upgrade, but am not in a hurry to do so.

 

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

I don't see RickyDean's virus issue when I try to save the page.  I am running Windows 11, using MS Edge.  (Just a data point for the site admins.)

[xdt99: New TI 99 cross-development tools available]

24 minutes ago, RXB said:

Yea I am a GPL programmer and this is the Assembly section as far as I can tell.

It is the installation instructions for all of the tools. If you can get to the point where you are invoking the assembler’s help instructions, the tools have been installed correctly. At that point you should be able to do something similar with the gpl assembler.  That is, get the help for it.

[xdt99: New TI 99 cross-development tools available]

Windows install guide here: https://github.com/endlos99/xdt99/blob/master/doc/WINDOWS.md

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

16 hours ago, JasonACT said:

Ah, that's one more TI working then.  Attached is one last attempt (another NOP added conditionally) to see if I can't get this working on them all.

Works on all 3 of my TIs.  Sams burn-in ran at 3 times on each.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

18 hours ago, JasonACT said:

Here's another 266MHz 2MB SAMS firmware, I've conditionally included an extra NOP when the speed is set at 266MHz or above.

I was able to test this on my 3 TIs.  It passed on 2 of the 3: Silver TI and QI TI.  For some reason the SAMS burn-in fails on the beige one.

 

I will probably just use the 264 mhz versions.  As I said before, I am perfectly happy with those. 

 

Of course I am available to do testing should you release new firmware.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

Well glad to help, and thank you for the Pico PEB!

 

I thought I'd run some more tests yesterday.  I tested the 266mhz 2MB SAMS firmware, and the results weren't good for me. 

 

The beige and silver TIs had errors when doing the memory test. This was with the FG as well as with the Pico cart functionality.

The QI TI was able to run 3+ passes on the memory test.  FG only, as Pico carts don't work on the QI.

 

If you want to see screenshots of the errors, I can post them.

 

I am plenty happy with the 264 mhz firmware though, and will be using that for now.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

The 264 mhz 2 MB firmware works on all 3 of my TIs.  I get 3+ passes in the memory tester.

[Pi Pico[W] Peripheral Expansion Box Side Port Device]

Here are more results from my testing as well.  I only tested a single PI, but it seems they both run at 266 mhz.

 

I tested these firmwares: 252 mhz (1MB SAMS), 260 mhz (2 MB SAMS), and 266 mhz (1 MB SAMS)

 

These all passed the SAMS burn-in (3+ passes) on both the silver TI and the beige TI.  I tested using the onboard cart functionality (without FG).

 

I hadn't mentioned it before, but I have another beige TI.  It came with a Mitsumi keyboard, which isn't working.  I did a keyboard swap so I could do some testing using the PI Pico.  The TI is a QI model (non v2.2 1981 ROM), so it has potentially some differences in the motherboard timings.

 

I had to test with the FinalGROM on the QI TI because the Pico onboard cart would not work.  I was able to choose the cartridge but after the reset, the cartridge would not show as an option.

 

In any case, I tested using the same firmwares as the other two TIs.  All passed the SAMS test.

 

I will try to test the 264 mhz 2 MB SAMS firmware next, as the others have been accounted for.