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99/5 TI documents Quest

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Well, I just happened to be browsing the forum at the right time. Back in 1998 I talked with a person who had a binder full of 99/5 documentation. He photocopied it for me and was going to send it to me, but some house moves occurred and it got forgotten about in all the moving. Anyway, he might still have the docs, and maybe could send you the photocopies he made if he still has those. His name is Erik Olson. He was still active on the TI groups as recently as 2012, so he should still be out there lurking.

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Hi Bryan,
Thank you for your reply !

I contacted Erik a few years ago about his TI-99 prototypes et peripherals, he told me that he has sold most of his TI stuff, only very few documentation remained, he still has got some papers like a documentation about test data for the TI-99/4 (not A) cassette output (maybe interresting for you) , but nothing about the 99/5 ou 4B for exemple.

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Micheal Becker had a TI-99/5 unit in 1999 I know. There's also this article from 1994:


By Glenn Bernasek

(March 1994)

TI-CHIPS Cleveland, Ohio



What you are looking at are UN-retouched pictures of an actual TI-99/5! Yes, you read me right! This is a real TI- 99/5. I for one didn't think there vas such a thing, and I'll be the first to admit it! (My sincere apologies to Messes Cohen and

Woodward.) It wasn't until I posted a message on comp.sys.ti that the 99/5 didn't exist; that I received an e- mail missive that informed me that the TI-99/5 did indeed exist!


The first thing I did was to send an e-mail reply offering to buy this machine or at least get some form of documentation. Well TIers, needless to say, I had to settle for sole pretty super photographs, and here's a couple of what was sent to me.


The owner informed me that the TI-99/5 or 4B was being developed to replace the 99/4A when TI pulled the plug.

(Probably to go head-to-head with the C-64. THE 5 WOULD HAVE WON HANDS DOWN!)


Anyway, here's what was built into the TI-99/5.


1. The cassette port vas replaced with a hexbus port. (The

hexbus was an eight wire, four bit wide communication cable,

Devices designed for the hexbus Included a floppy disk controller, a serial port, streaming tape drive, 80 column video controller (doesn't that make your mouth water?),

portable printers and portable plotters, to name most of them.

In a way It was a return to the old “choo choo train"



2. The insides were greatly simplified by the transition to

the 9995 processor!


3. The TI-99/5 also had the 32K memory expansion and

speech synthesizer built Into the console.


If you still have doubts, a chip on the motherboard picture has a white label on it. The label reads, in part, '99/5 11/22/83' and “TI-99/5” is prominently printed on the circuit board!


There are probably sole of you who will be fortunate enough to say, 'Yeah, I've seen one of those before in a garage sale or at a Faire.' You are very fortunate Indeed because there were ONLY TEN TI-99/5s MADE! I think this makes the TI-99/5 a pretty rare animal, don't you? I'll be carrying the original photos around with me to show to those who would like to take a look at the FABLED TI-99/5.


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I only had a memory map document for the 99/5, Fabrice--and you have that already. Unfortunately, no 99/5 information was in the collections of data I've acquired over the years from three different TI engineers who were members of the design teams for different 99-related products. I was able to assemble most of the information on the 99/8, a little on the 99/4B, and a lot on the various PEB cards that were in development. I'm not sure if I've put up the main document identifying specifics of the 99/4B yet--but I think I've scanned it. I'll try to put it up on WHT in the next few days if I do have it scanned.


I also have a prototype motherboard/daughter board for the original 99/4--but the rest of the surrounding machine was scrapped by the previous owner, as he had no clue what it was--and he was just saving the parts he thought would be able to sell as electronics scrap.

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The best thing to do is run down Erik Olson and see if he can provide you with the name of the person he might have sold the 99/5 docs to. Right now that would be your best option. Here some neat 2009 info from Erik:



At first, the TI-99/4B was a minor upgrade to the 4A planned to reach the market in June 1982. In January 1982, the design of the 4B was:


Same 9900, 9918A, 9919A chips


ROM expanded from 8K to 16K paged.


Scratch pad ram 8 times larger. Fills >8000 to >87FF with a hole for sound chip address



RS232 printer out replaces CS2. There would be a new Y cable to connect both a cassette recorder and a TI Impact Printer.


New ROM with Extended Basic was considered but not expected to make it in.


Meanwhile a TI-99/4B revision of TI Basic was specified which would use the extra RAM.

The 4B would still have 3 GROMS. TI Basic would use the additional 8K ROM as well.


The 4B anticipated using more 9900 assembly in GROM, for download to the expanded scratchpad RAM.


Some part changes:

2x6810 SRAM replaced by 4x TMS2114 SDRAM VDP ram TMS4116 replaced by a more expensive chip

3 TTL chips replaced by 12L6, 16L2 PALs

9904 clock chip, 48mhz Crystal replaced by 12mhz (already planned for 4A)


A constraint for the 4B was no changes in plastics or styling. The 4B was to be compatible with all Command Modules in GPL or assembly language.

Another goal was cost savings through 0.5 hour less labor and $5 less parts. However, the 4B parts were going to cost $21 more, with the ROM and RAM upgrade eating up any savings. In fact, even the PAL chips cost more than the ICs they replace.



TI-99/4B Product Specification 18 Jan 1982 TI internal memos


I believe this plan was changed soon after - and a 9995 was contemplated instead. I have one memo quoting a 9995 cost for the 4B. This could have evolved into the 99/5.

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@Bryan: Thank you again for your interest.
The 99/5 owned by Michael is mine, he kindly accepted my proposal and sold it to me in 2002. The article written by Glenn Bernasek in March 1994 and the one gave by Erik Olson about the /4B are already parts of my documents collection that I have assembled during the years. The /4B and /5 are two related but different projects. Both are very interesting :-)
I'll try to contact Ron Wilcox, thank you!

@Jim: Yes, I have already this document. The documentation that you've assembled is already great! I cross my fingers for you'll find new documents again.
I would be so happy to see some pictures of your motherboard/daughter board for the original 99/4, It would be a rapture for my eyes!

Thank you so much to have saved this master piece!

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Yes, My TI-99/5 is fully fonctionnal :-)
Since it arrived at home, I took an extremely care to preserve this computer in good condition of use.
I regularly clean the electronic of the motherboard and also of the power supply to be sure that it receives stable tensions.

Of course, I can dump the EPROM for you :-) I had already dumped this EPROM but the file is stored in one of my computers left in a distant house. The quicker is to re-dump the EPROM.

The prototype is equiped with the TI-Basic (3 COB GROM chips on a mini PCB). No Extented Basic inside, alas) but the working E/A cartridge permits me to launch many programs coded for the 99/4A. I have made the HX5102M clone especially for the 99/5: to be able to load programs stored in floppy dsks.
Here is a link (already posted on AtariAge): http://www.ti99.com/misc/hexbus/HX5102M2.mp4
The video shows my HX-5102M working on the 99/5 (opened, to have the pleasure to see its electronic):
Some programs crash (but many of them work) which is not surprising because the 99/5 has many special and new hardware. Non-working cartridge: TI-Exetended Basic but most of the other TI cartridges work, with (for some of them) a new pleasure... the speed! The speed scrolling and sprites moves are amazing in Parsec! So rapid that it is very difficult to refuel in speed 1! I can make a video of the 99/5 playing Parsec if you want to see :-)




1 CPU TMS9500 2 MP9807 3 VDP TMS9129NL 4 Speech Synthesizer TMS5200 5 ROM Speech 6 System ROM 7 CF40067 8 RAM Mapper TMS4500 9 DRAM TMS4416 X 6 10 I/O Controller TP0381 11 Keyboard connector 12 Joystick Port DB9 13 Hexbus port 14 K7 port DB9 15 Video connector DIN 16 GROM port (cartridges) 17 TI Basic GROMs 18 VRAM TMS4416 X2 19 Audio chip SN76496 20 Power connector 21 Unkwown connector (support for additional ROM/GROM?)


Edited by fabrice montupet
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I already own one of the best computers in this world - a Geneve 9640, so I know what real performance looks like. :)


As I said, the 99/5 is more like a long-term goal, and I must be careful not to let me distract from all those things that wait for completion. Maybe some day I can raise enough interest in someone on this list to pick up that challenge.


So yes, please preserve it as good as you can.

Edited by mizapf
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Nice idea to implement the 99/5 in MESS! But it will be a hard part to implement the unknown chips like the MP9807 or CF40067. What do you think, Michael?


And Fabrice, please show us the difference between the 99/4a Parsec and the 99/5. Is it possible for you to show both parsec sessions side by side? That would be great!

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One of those is possibly the Hombre chip designed for the 99/4 LPC (Lowered parts Count) computer, also called the 99/4B. We have the specs for that chip up on WHT in with the 99/8 documents.


The I/O chip may be a variant of the Hex-Bus chip used on the 99/8 as well, so we have some possible places to start.

Edited by Ksarul
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It's done :-) I just made a video of Parsec on the Home Computer 99/5.
I also thought about a video showing Parsec on the 99/4A and the 99/5 at the same time, but it was hard to do because I had to play exactly the same way. And then, I said to myself that everybody who's used a TI-99/4A already has played Parsec, so you'll be able to see the difference :-) You will notice that I avoid to let the fire key pressed, it can be done with the 99/4a during few seconds until the ship overheats and explodes, but on the 99/5 the ship explodes too quickly.
Here is the video. (sorry for the brightness changes on the first sequences, it's due to automatic correction done with an iPad, it's not a real (and good) camera): http://www.ti99.com/misc/hexbus/Parsec-ti99-5.mp4

Edited by fabrice montupet
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The easiest way is not to play on both sessions, then they are identically. ;-)


It seems it would really hart to play. Its seems that the fuel tunnel scrolls too fast, so you miss the entry all the time.

Edited by HackMac
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Nice idea to implement the 99/5 in MESS! But it will be a hard part to implement the unknown chips like the MP9807 or CF40067. What do you think, Michael?


I'd do that the way it is done with all other custom chips. For instance, we cannot look inside the Gate Array of the Geneve, but its functionality is documented well enough. If we understand what the chips inside the 99/5 actually do - with the help of the ROM dump - we can try to implement them by functionality.


By the way, since MAME's and MESS's rationale is to preserve all kinds of arcade and computing systems - even the rare ones - such an attempt would be more than welcome, also by the other devs. However, I just cannot afford enough time for it. I'm in dire need of some more helping hands.

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I have replaced the video by an other one (same link, gave in my previous message). Added a normal mode sequence where the speed of Parsec is like it could be played on a 99/4A. The video has also been cropped in 4:3 for a best display.
Yes, enter into the tunnel is hard, Sometimes, I do but when the tunnel becomes more longer, the speed of the scrolling is too high to go out of it.

Edited by fabrice montupet
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Hi Fabrice,


The TI99/5 appears to use a TMS9500 processor, a TMS9995 derivative. Karl Guttag (the 9995 designer) does not recall such a derivative version ever being made, but is was long ago and he does not exclude the possibility that the home computer division used a different number for the same chip. Do you have a photograph of the actual on-chip markings? I'm not doubting you, but would like to see if I can dig up more info on this chip.


By the way, here is a memo from the home computer division asking for revisions to the tms9995:


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pnr, thank you so much for this memo! I didn't kwow! It is full of interesting informations.


The sticker than you can see on the picture of my 99/5 motherboard has been removed. I took it off many years ago, in the hope of discovering an inscription on the CPU. Alas, no information on it, graved or painted :-(
Long time ago, I had read somewhere that the 9500 was a 9995 on which a feature has been modified, but no information about this feature... My doubts were focused on the 256 bytes of on-chip RAM but I have absolutely no certitude.


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