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TI Mini Expansion System


Artoj
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Hi All,

I just received my prototype board for the TI Mini Expansion System, it uses Peter Schuberts AT mini system cards from about 1986. I will post more info soon, here are some pics. Please note there are empty 40 pin sockets, these are there for adding a RP Pico or an ATMega 32, for future expansion. Regards Arto.

 

 

MiniExpVer1.JPG

MiniExpPicVer1.JPG

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Two things on the SAMS board: the memory chips to make it into a 4096K board are really finicky (and seriously expensive new--over $120 each). That said, you might want to stay with the 512Kx8 chips for 1M. The other thing is the footprint on U16 looks like you used a .400 chip here, which is probably wrong unless you are using a really odd chip (.400 chips are not at all common).

 

It definitely looks interesting. . .

 

 

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Thanks speccery, I use EasyEDA at the moment, looking at using Kicad. As an Artist the interface is where the rubber hits the road,  I have used Diptrace for a few years, also Express PCB before that. Each has there niche design advantages. I started on AutoTrax and even made my own using Corel, so much good software now, I was even working on a TI99 version at one point, maybe when I make the V9938 card I might start programming in earnest. 

I hope to finalise my PCB work for the TI very soon, I am looking forward to making a TI card that interfaces with my Basic Ternary Computer design, one gate at a time, one computer function at a time. I am so amazed at the TI community, there are so many talented engineers and hobbyists. I would say without a doubt that the TI99 has proven to be a unique machine that seems to attract the most gifted. Regards Arto.    

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Thanks @Artoj interesting to hear what people are using. I used to use eagle but have recently moved over to Kicad. I am still very much in the learning curve, but I have already created 6 PCB designs with it. Every single one has worked. Still kicking myself for not making the move earlier. But as you know, there's always a learning curve and each one of these programs has its own kinks. The nice thing about Kicad is that it's now so widely used that there's a lot of information available, as well as plenty of reference designs.

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One note on the quirks of the Mechatronic design and the TI console: the console power up routines set a few VDP variables that have no meaning on a 9918/9929 system, but which have strange effects on the 9938/9958, as those settings mean something to the later chips. The console comes up with a black screen when entering BASIC. Easily reset (there is a program to do so in the Mechatronic manual), but a pain nonetheless. Not a reason to avoid this project, but it is some useful background data to help avoid confusion during project realization.

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17 hours ago, Ksarul said:

One note on the quirks of the Mechatronic design and the TI console: the console power up routines set a few VDP variables that have no meaning on a 9918/9929 system, but which have strange effects on the 9938/9958, as those settings mean something to the later chips. The console comes up with a black screen when entering BASIC. Easily reset (there is a program to do so in the Mechatronic manual), but a pain nonetheless. Not a reason to avoid this project, but it is some useful background data to help avoid confusion during project realization.

Sorry to advertise my own project - but this is something which probably can be fixed with a TI-GROMmy board.

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Thanks Ksarul and speccery,

There is a momentary switch to enable the external interrupt(sets Low EXTINT Card Edge no 4) via a 74HC125A, to reengage the console from a blank screen and allow the V9938 to initialise. If that does not occur and you have no issues, turn off the console and then slide switch 2 of dip 2 to off, then all is OK. It all depends on which version of TI Console you have. The TI Basic sends VDP register codes while powering up that is not compatible with the V9938. In the future versions I hope to make this procedure redundant or speccery by his TI-GROMmy and could by pass these codes depending if the V9938 is on board. Regards Arto  

 

Dip SW2
S1: ON = NTSC. OFF = PAL
S2: ON = Button interrupt is allowed. OFF = button interrupt is not allowed. 
S3: ON = US ASCII. OFF = German Char Set

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Hi All,

Another first draft for the Mini card series, based on the Thierry Nouspikel IDE card. A few more cards (RS232, SD, USB, 48 bit IO , Ternary) should complete my work here before I start to work on some software, while I wait for lots of parts to arrive. Regards Arto. 

TI99-IDecardpicv1.png

Edited by Artoj
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20 hours ago, Artoj said:

Version 2 Draft, I cleaned up a few connections and decided to use the BQ4802YDW, so I added a battery. Regards Arto.    

 

you did put a 5k resistor between VSS and RST on the BQ4802 correct?  If not, the clock chip will not be detected.

 

 

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2 hours ago, Shift838 said:

you did put a 5k resistor between VSS and RST on the BQ4802 correct?  If not, the clock chip will not be detected.

Thanks, it was shown in the product sheet, it is now in draft v3. Regards Arto 

Edited by Artoj
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12 hours ago, Archimedes5000 said:

Can you share this with me on KiCad?

axel.ahlborn@online.de

Greetings Axel

All the files will be made public when all the projects are finished and working. 80% are already available as schematics on this site. 20% is both mine and Peter Schuberts work, not in KiCad format yet. Waiting for lots of parts and boards, then testing, testing, testing and some programming. Regards Arto.  

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Hi, sorry my mistake. I wanted to ask for TinkerCad because the pictures above look if you use TinkerCad. In TinkerCad you are able to share projects. Thats the Reason for my E-Mail Adresse above. My Tronxy x3s is a little bit older, but I am able to print 330x330x400 mm. Hope it should be enough for the STL Files. 

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46 minutes ago, Archimedes5000 said:

Hi, sorry my mistake. I wanted to ask for TinkerCad because the pictures above look if you use TinkerCad. In TinkerCad you are able to share projects. Thats the Reason for my E-Mail Adresse above. My Tronxy x3s is a little bit older, but I am able to print 330x330x400 mm. Hope it should be enough for the STL Files. 

Sure, I will share them, still I am not quite finished designing them. When I get the base board completed and at least one card made, I will go over the exact sizes, I want to make they sure all will fit nicely in the box. The lid has not been made yet, it will probably have an optional set of sockets for my Ternary expansion board. I was also considering adding a front area and a socket for future expansion as well.  I will email you soon when I have made some adjustments, regards Arto.   

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