Title says everything I want to know how to do. Well I mainly want to find a way to upgrade the RAM so less programs have to be archived. If anybody has any ideas on how to even start trying to this it would be highly appreciated!!

Not possible (without essentially building a calculator from scratch): http://www.cemetech.net/forum/viewtopic.php?t=8294&start=0

Why do you want your programs to be unarchived ? You can run archived programs with zStart and DoorsCS so I can't even understand the aim of unarchiving them.

DoorsCS can run programs from the archive. If you have a Ti 84+SE, you have like 3.5MB of free ROM, so you should really be set in the way of memory. 3.5MB ROM also means 93 app pages.


There IS a hack that a guy named thepenguin77 made (he's on omnimaga). He made a hack that frees about 12KB more RAM iirc. The hack is very unstable, though.

Nothing is impossible with electronics. You just have to have the right knowledge. And it's not that I need the space I really just want to find a way to do it.

I'm not so sure. From what KermM has said and others, the cpu on the ti 84+SE is all in one chip with the RAM and other core stuff. If you wanted to add a new CPU and RAM chip, its possible, but you'd have to make an entirely new ASIC.

Well is it possible to just disable that portion of the chip?

No, it's all built onto the same silicon wafer and it's impossible to change anything about it.

Indeed. Some of the older calculators have discrete RAM and a discrete z80 CPU, and I have a few of them in my collection, but they're fairly hard to find these days.

Well let's say that we could get all the hardware separately. Could I transfer the OS onto that hardware?

One COULD make a new ASIC if they had an illegally-obtained schematic from TI and a spare zilog z80 cpu (I do ), money, time, a compatible RAM and ROM chip, patience, time, and all the nano-sized chips and crap, a real pointy soldering iron, patience, a microscope, and a whole lot of aspirin. Oh and did I mention patience?

Yes, you could transfer the OS. You'd need a ROM, more specifically, because there would be no boot code/boot instructions on the ROM. It'd just be plain old piece of metal.

What you might want to consider doing is downloading/loading BrandonW's great programs, usb8x and msd8x. Usb8x is a usb peripheral driver for the ti 84+/SE and msd8x is the GUI to run usb8x. All you'd need is a Usb A Female to Usb A Mini Male converter cable. That way, you can use a flash drive/mouse/keyboard with your calculator. The flash drive feature will allow you to store whatever the heck you want off the calculator and all you have to do is load/erase the programs to your calculator as you please.

That would be exactly what I mentioned in the first place (building a calculator from scratch).

I think of building from scratch as designing it too. I've already got the design not the parts though.

You don't have the design. That implies you have the schematic for the ASIC, which you do not have, and you're not going to be able to get easily.

If you want a schematic, you should probably hit up KermM. HE has the most knowledge of the hardware onboard these calculators.

The ASIC is fabulously complex, more like a coprocessor than some simple PLD sketch. Your best bet would be to find one of the old calculators with a discrete z80, RAM, Flash, and ASIC, and try to work with that, but even so simplified it would take a lot of EE experience and skill to do what you're proposing.

You know what would be a much better choice? Grab a TI-86, and modify it to have a Flash chip for archiving. The 86 has 128k of RAM, but only around 96k useable. (most of the rest is still unused, so it's safe to use in assembly programs anyway)

People have done this in the past, but now the hardware they used is so old it's hard to get ahold of anymore. The schematics are also difficult to find, as the site hosting them has gone the way of the internet, but fortunately The Web Archive did a backup, including images.

Note that even while we think we have all of the documentation, we are still proven wrong. Take ports 0x0E and 0x0F. We had the completely wrong idea what these were for before the TI84PCSE. Also, look at the USB. Most of the documentation lives in the mind of BrandonW and I doubt that he knows what every bit of every USB port does (Although I would love to be proven wrong ).

If a BASIC program has sub-programs, only the main program can be archived. (unless you use an ASM lib to copy/unarchive archived programs temporarily)

You'd have to rewrite many parts of the OS. The Z80 itself requires help from extra hardware to access more than 64 K of data. The OS code that manipulates regular variables isn't programmed to use that hardware. In fact, the current one goes out of its way to ensure you CAN'T trick it into doing so.