TI-74 TI-95 8x32K banked RAM/FLASH cart soon, ROM images needed

[Jeff_Birt]

A friend and I have been working on new 8x32K banked RAM/FLASH carts for the TI-74 and TI-95. The carts size and the fact that TI chose to put the female connector on the cart presented a packaging problem. My friend (known online as Stardust or The Fugu) managed to fine a connector that would work and squeeze all the components into the space left over. There was just enough space left over that I managed to wrap a nice 3D printed case around it, which slots into the machine nicely. 

Some images are attached. The one of the enclosure is a 3D rendering, with the rear part of case 50% translucent. The rear part of the case snap on/off to provide easy access to the DIP switches. I have printed these but have not taken a picture yet. 

While the carts are electrically and physically exchangeable the firmware is not.  We could however load all 8 known images onto one FLASH cart and the user would need to take care to select the correct ones for the machine they are using. It is also possible for the user to install ROM images on the RAM cart using TIFF/TIFF2 and then use the write protect switch to prevent overwriting the contents.

It would be nice if we could include the known original ROMs with the FLASH cart. So far, we have only found three thanks to another friend who had dumped them. Below is a list of the cart images we have and those that we do not have. If you happen to have the missing carts and can or have dumped them, we would appreciate getting a copy. If you have the carts and would consider loaning them to us to be dumped perhaps, we can work something out.

Images we have for TI-74
•    Finance
•    Math
•    Pascal


Missing TI-74
•    Statistics
•    Chemical Engineering


Missing TI-95
•    Statistics
•    Math
•    Chemical Engineering

[RPNerd]

This is a project that I'd be interested in. Sadly I have no ROM cartridges that I can donate but I would be very interested in getting one of these when the time comes, particularly the Pascal ROM for TI-74.

[rprosperi]

I agree, I will be getting one of these!

I have one of the ROMs for the 95, but don't recall which one. I'll dig into my TI stash in the next week or so and once in-hand, I'm happy to send it to you (Jeff) to extract the image to load and share. I'll contact you when I have the module.

And thanks to you and your pal for the effort to make and share these, no doubt many readers here have long wondered about trying out some of these rare devices.

[Jeff_Birt]

(10-12-2024 11:57 AM)rprosperi Wrote:  I agree, I will be getting one of these!

I have one of the ROMs for the 95, but don't recall which one. I'll dig into my TI stash in the next week or so and once in-hand, I'm happy to send it to you (Jeff) to extract the image to load and share. I'll contact you when I have the module.

And thanks to you and your pal for the effort to make and share these, no doubt many readers here have long wondered about trying out some of these rare devices.

Thanks Bob, the modules come up on eBay infrequently. Would love to have them all archived for all to have access to.

[Jeff_Birt]

(10-12-2024 07:02 AM)RPNerd Wrote:  This is a project that I'd be interested in. Sadly I have no ROM cartridges that I can donate but I would be very interested in getting one of these when the time comes, particularly the Pascal ROM for TI-74.

I should have a few ready shortly. Got the user's manual back from another friend who is an excellent proofreader and beta tester. If we can get the remaining ROMs we can preprogram the FLASH with all of them. (Of course, you can reprogram the FLASH with whatever you want was well. It uses the same programming adapter as the 'Dial-A-ROM' products.)

[Gene]

Jeff - let me dig too. I may have the others in my stash. Let me see.

[Jeff_Birt]

I have the missing TI-74 carts on the way. The fella who had them found a couple of 3rd party carts too which is exciting. I did not know any 3rd party carts were made.

[badaze]

(10-12-2024 06:23 PM)Jeff_Birt Wrote:  I have the missing TI-74 carts on the way. The fella who had them found a couple of 3rd party carts too which is exciting. I did not know any 3rd party carts were made.

TI 74 were used by insurers and car resellers.

[Jeff_Birt]

Some glamor shots of the case. Realized last evening I forgot the detent dimples so those have been added now. This PCB version uses regular DIP sw so the rear of the cover comes off for access. Next version we are going with piano type vertical mount DIP sw which will be accessible from a hole in the rear cover.

Pic1

Pic2

Pic3

[Dave Britten]

I am definitely interested in a couple of these once they are available to order.

Are there any plans for an eventual RAM+flash ROM combo module? I would mainly want the RAM, but having the ROM images available by flipping a few switches would be handy.

I have both the Math and Statistics modules for the TI-95, by the way.

EDIT: And I was able to find my CI-7 cassette interface, so if there's a ROM-dumping program for either the 95 or 74, I could load it via WAV and save the ROM dump back to tape/WAV.

[rprosperi]

Looking great Jeff, I too will be needing 2, 1/ea for 95 and 74. Is it clear that the only modules ever produced are the 5-6 you listed above (not counting 3rd-party units)? If so, that was a lot for effort by TI, to only release 2 or 3 modules for each machine. I suppose a lot less effort than building the TI-88 and then cancelling it, but still, non-trivial amount of time and effort...

[Jeff_Birt]

(10-14-2024 09:59 PM)Dave Britten Wrote:  I am definitely interested in a couple of these once they are available to order.

Are there any plans for an eventual RAM+flash ROM combo module? I would mainly want the RAM, but having the ROM images available by flipping a few switches would be handy.

I have both the Math and Statistics modules for the TI-95, by the way.

EDIT: And I was able to find my CI-7 cassette interface, so if there's a ROM-dumping program for either the 95 or 74, I could load it via WAV and save the ROM dump back to tape/WAV.

There is not enough real estate for RAM + FLASH + battery. You can also add ROMs to the RAM cart and set the write protect switch to keep from overwriting it.

I have three FLASH and three RAM available at this time. These are 8x32K banks each. Toward the end of the year the 16x32K bank versions should be ready. I don't want to ship the FLASH until I'm able to program in all the available ROMs.

I just grabbed a near mint TI-95 lot which included all three TI-95 carts

[Jeff_Birt]

(10-14-2024 10:52 PM)rprosperi Wrote:  Looking great Jeff, I too will be needing 2, 1/ea for 95 and 74. Is it clear that the only modules ever produced are the 5-6 you listed above (not counting 3rd-party units)? If so, that was a lot for effort by TI, to only release 2 or 3 modules for each machine. I suppose a lot less effort than building the TI-88 and then cancelling it, but still, non-trivial amount of time and effort...

I read elsewhere that TI did not release an SDK and were the ones who developed the 3rd party carts. Kind of an odd business plan.

I have three FLASH and three RAM available at this time. These are 8x32K banks each. Toward the end of the year the 16x32K bank versions should be ready. I don't want to ship the FLASH until I'm able to program in all the available ROMs.

I just grabbed a near mint TI-95 lot which included all three TI-95 carts

[dmh]

Put me down for 1 or 2 of these too :-)

Have you worked out the price yet?

[Dave Britten]

(10-14-2024 11:34 PM)Jeff_Birt Wrote:  There is not enough real estate for RAM + FLASH + battery. You can also add ROMs to the RAM cart and set the write protect switch to keep from overwriting it.

Yeah, I figured there wouldn't be nearly enough space to fit both chips on the board. Wasn't sure if there was some neat hybrid SRAM + flash chip you were eyeing for future revisions. I think adding ROM images to the RAM cart should be plenty sufficient for most purposes.

What is the transfer mechanism for getting ROM images into the carts? Some kind of USB/TTL cable with the pins stuck into the cart connector?

(10-14-2024 11:34 PM)Jeff_Birt Wrote:  I just grabbed a near mint TI-95 lot which included all three TI-95 carts

Nice! The Math and Statistics ones will no doubt have the broadest appeal. The Chemical Engineering module looks like it has a lot of good stuff, but it's obviously going to have a much narrower audience.

[dmh]

I read in another forum that the 74 only recognises 8Kb of RAM and the 74S will recognise 32Kb.

Have you tested and can you advise?

There was also mention that it could be ROM dependent.

Does the calculator know the different between RAM and ROM as it can recognise 32Kb of ROM?

Just thinking about the option of loading ROM into your RAM module and having it work in a standard 74.

(10-14-2024 11:34 PM)Jeff_Birt Wrote:  

(10-14-2024 09:59 PM)Dave Britten Wrote:  I am definitely interested in a couple of these once they are available to order.

Are there any plans for an eventual RAM+flash ROM combo module? I would mainly want the RAM, but having the ROM images available by flipping a few switches would be handy.

I have both the Math and Statistics modules for the TI-95, by the way.

EDIT: And I was able to find my CI-7 cassette interface, so if there's a ROM-dumping program for either the 95 or 74, I could load it via WAV and save the ROM dump back to tape/WAV.

There is not enough real estate for RAM + FLASH + battery. You can also add ROMs to the RAM cart and set the write protect switch to keep from overwriting it.

I have three FLASH and three RAM available at this time. These are 8x32K banks each. Toward the end of the year the 16x32K bank versions should be ready. I don't want to ship the FLASH until I'm able to program in all the available ROMs.

I just grabbed a near mint TI-95 lot which included all three TI-95 carts

[rprosperi]

(10-14-2024 11:35 PM)Jeff_Birt Wrote:  

(10-14-2024 10:52 PM)rprosperi Wrote:  Looking great Jeff, I too will be needing 2, 1/ea for 95 and 74. Is it clear that the only modules ever produced are the 5-6 you listed above (not counting 3rd-party units)? If so, that was a lot for effort by TI, to only release 2 or 3 modules for each machine. I suppose a lot less effort than building the TI-88 and then cancelling it, but still, non-trivial amount of time and effort...

I read elsewhere that TI did not release an SDK and were the ones who developed the 3rd party carts. Kind of an odd business plan.

I have three FLASH and three RAM available at this time. These are 8x32K banks each. Toward the end of the year the 16x32K bank versions should be ready. I don't want to ship the FLASH until I'm able to program in all the available ROMs.

I just grabbed a near mint TI-95 lot which included all three TI-95 carts

I sure find it strange that TI would release an expandable product, the follow-on for the hugely successful Ti-58/58C/59, but then only release 2 application ROMs. It's really no wonder it didn't do well, but I guess TI was shifting it's focus to other markets, like education, where they did a bit better, so maybe the right decisions after all....


I don't need one any time soon, so please let others grab the current carts available, as I'll not have any time to explore them for several months, too tied-up with other projects, but I do want to get some eventually.

[brouhaha]

(10-14-2024 11:35 PM)Jeff_Birt Wrote:  I read elsewhere that TI did not release an SDK and were the ones who developed the 3rd party carts. Kind of an odd business plan.

For the TI-74, there might not have been an "SDK", but there was definitely software developer documentation on the internals, which was hundreds of pages, and much more comprehensive than the "TI-74 BASICALC Technical Data Manual" which can be found online. A friend worked at a company that developed their own software for the TI-74, and programmed their own EPROM modules. Years ago my friend gave me his copy of that documentation, but unfortunately I no longer have it.

I have no idea whether there was any comparable internals documentation for developers for the TI-95.
[/quote]

[Jeff_Birt]

(10-15-2024 06:19 AM)brouhaha Wrote:  For the TI-74, there might not have been an "SDK", but there was definitely software developer documentation on the internals, which was hundreds of pages, and much more comprehensive than the "TI-74 BASICALC Technical Data Manual" which can be found online. A friend worked at a company that developed their own software for the TI-74, and programmed their own EPROM modules. Years ago my friend gave me his copy of that documentation, but unfortunately I no longer have it.

I have no idea whether there was any comparable internals documentation for developers for the TI-95.

This perhaps: https://www.scribd.com/document/34233052...manual-pdf

[Jeff_Birt]

(10-15-2024 01:51 AM)dmh Wrote:  I read in another forum that the 74 only recognises 8Kb of RAM and the 74S will recognise 32Kb.

Have you tested and can you advise?

There was also mention that it could be ROM dependent.

Does the calculator know the different between RAM and ROM as it can recognise 32Kb of ROM?

Just thinking about the option of loading ROM into your RAM module and having it work in a standard 74.

The TI-74 can indeed only see 8K of RAM though it has no problem with 32K of ROM. As you mentioned the 74S can access the whole 32K. The TI-95 does not know to look for more than 8K but there is a hack to write into the memory available registers (from keyboard) to let it know 32K is available. All the address lines are there on each model but the ROM just does not know to look for more than 8K.