OK, back story, I'm particularly interested in the TMS9900 because my dad used TI 990 machines in some way in his first job out of school at Chrysler (maybe as a CAE machine and embedded development platform for early auto electronics he was working on?) so, growing up, poring through the bookshelves, I would stumble across documentation for this "strange" TI 990 system and I've always been kind of intrigued by it... I've never seen a TI 990 system in the wild, and only a few folks are displaying 990 architecture SBCs or actual TI-990 systems so the obscurity factor is there a little bit... Last but not least the architecture is somewhat unique and the instruction set is nice. I was visiting my parents over the holidays and, being the more historically inclined of the two of us, offered to help my dad get rid of some old obsolete "ephemera" ;) So, amongst a fairly huge "data dump", my dad set me off to start with a large binder left over from an introductory seminar on the 990 from the 70s and a few ICs from his junk box... TMS9901s... we couldn't find any CPUs for some reason though my dad was certain he had a few kicking around somewhere. We'll look again next time I visit. I did some research and it seems that straight TMS9900s are hard to find (and harder to find cheap) and they are frustrating to work with because they require three different voltages to operate, and four clocks (ideally supplied by the equally difficult to find TIM9904). So, I'm with you, I did decide to use the TMS9995 to do my 990-architecture machine. (I'll just use my stock of DIP 68000s when I want to build something with a 16-bit data bus...) The reason I asked here is that I'm really wary of the parts from China and Hong Kong, I have read a lot of stories where people have bought these ICs and they have turned out to be completely re-marked, totally bad, somewhat defective, etc. I'm trying to find a local source if I can... I was able to source the 9995s locally from a guy here in MI... I got the 9901s from my dad. Just need a few 9902s and I should be ready to roll... if I get desperate I might try the China suppliers but I'd rather get it from a list member, or at least an onshore eBay seller. Has anyone bought ICs from one of these Chinese suppliers and found that they were bona fide and in general functional (I know, now 100% guarantees on random old ICs...)? I'd be very interested to hear endorsements. The offshore sellers have a lot of interesting old ICs and the prices are in general very low... I would go to town if I felt safer, LOL. I have seen those parts kits you mention and I have wondered about them as well... I assume they are targeted at guys like me, people trying to build home brew 990 machines? I do wonder about the origins... I could believe they were maybe 99/4a machines at some point in time sent overseas to be scrapped, with the remainder... the EPROM, SRAM and glue, made up from other sources. However, I've closely scrutinized a picture of the 99/4a motherboard and I don't see a TMS9902 on there so it might not be so easy to just say, oh, someone pulled all the bits off a 99/4a and threw some extra stuff on top; I'm just not sure. Best, Sean On Sat, Jan 3, 2015 at 10:55 AM, Al Kossow <aek at bitsavers.org> wrote:

On 1/3/15 9:25 AM, Sean Caron wrote: I have at least 6 990s (/4 /10 /12) and several truckloads of boards/documentation/software that no one here has expressed any interest in after talking about them a couple of times over the years. Dave Pitts has several and has written an emulator that runs most of the OSes for them http://www.cozx.com/~dpitts/ti990.html

On Sat, 03 Jan 2015 10:31:24 -0800 Al Kossow <aek at bitsavers.org> wrote: Too bad they are 3000 miles away from me; shipping would be a killer :^(. Can't count the times I had 990 stuff lined up to get, and, well, stuff happened. C'est la vie, etc. Still have my /10 and BS1500, though, incredibly, and most of my 4A and Geneve stuff, although not all in the best condition, now. Hanging on to it all through a lot of trials, trauma, and general BS turned me into a bit of an antisocial jerk for a while, but I'm still glad that I did. For Caron: I followed this thread with interest, because lately I've been considering some 9900/9995/99000-based projects, and/or add-on cards for 990's and even 4a's, or maybe a homebrew, so the chipsets on Ebay look promising. Look like some kind of 9900 and 9995-based MSX2+ SBC's, like a souped-up Tomy Tutor or something. Those Altera chips would be the key to system, but I don't see any mention of documentation, schematics, etc. Presumably these are hot hobbyist items in Japan or the MSX community, and are well-documented somewhere, but I'm not familiar with them. The 9902 is not present in the 99/4A console. You need an RS/232 peripheral or card for that. Readily available from any of sources, though, like Al says.

I loved the 9900! it was screaming fast compared to x86 in 1980 or so. I bought one of their SBCs, the TI 990 'University Board', it came with a 200+ page course and tutorials on the processor. Later found their video chip 9918 and adapter board from Eyring Research. Other than the 99/4 these parts had little use. TI did make another stab at video chip coprocessors that ended up in the Truevision (AT&T) AT-VISTA framegrabber boards. Some trivia: The TI processors had lots of use in TI's industrial PLCs, the PM520 and PM550. I was in a design meeting with these guys, when management said 'What can we do with the PLC line to compete with Allen Bradley?' One of the more vocal TI engineers stood up, and said, 'Don't force us to use TI processors.' Their next gen PLC, the 560, was a standard bus, VME and 68000 based. I think it still ships today under the Siemens brand, TI sold off the PLC group and got out of programmable logic controllers altogether.

On Sun, 18 Jan 2015 07:06:06 -0800 Al Kossow <aek at bitsavers.org> wrote: Point taken. I'm updating my website and will put something up. jbdigriz