Run different os

[megatroy]

Hi

I would be interested to know if there is any possible way to run the ti-89 os on my ti-84 calculator.

Any answers would be appreciated.

Megatroy

[Cure]

I'm afraid it's not possible. The TI-83+/84+/SE family of calculators uses a Zilog Z80 processor, while the TI-89/TE family uses the Motorola 68000 processor.

[Harrierfalcon]

I believe the closest you can get is by using Emu8x, but it only supports up to 86 as far as I know.

[Cure]

Emu8x only runs the OSes the run on Z80 calcs. You can't run a 68k OS on a Z80 processor without making changes to the OS.

[DarkerLine]

Running a TI-89 OS on the 84+ would also be impossible because the 89 is much more powerful than the 84+, and as mentioned the 68k and z80 difference is also a big deal. However, if you're looking for the mathematical functionality of the 89, you may be interested in Symbolic, an application for 83+ series calculators which has a lot of useful functions in it, notably one for symbolic differentiation.

On a related topic, is there a way to run a TI-73 OS on a TI-83+? The processors should be compatible, and I don't see a reason why not, but I'm not an expert in the subject and I don't even know how to get it on the calculator (I'm sure TI-Connect will complain if I try the simple way).

[Recursive Acronym]

[critor]

I've tried with TILP to send a TI-73 OS file to a TI-83+.

The calculator displays "Receiving OS 0%", but TILP immediately stops sending by displaying "ERROR: NACK received".


Does anyone know a way around that?

[FloppusMaximus]

You're not *supposed* to be able to do that. The TI-73 OS gets rejected because it's marked as a TI-73 OS, not a TI-83+ OS.

To get around that:
- replace the header block with one from an 83+ OS
- mark OS as pre-validated (change value at address 0056 to 5A)
- ...
- profit

If you do so, you'll also find that the large font is not displayed properly (due to a possibly-intentional boot code bug on the 83+) along with various other minor issues.

Won't work on an 83+ SE or any 84+, of course. (It might be possible to get the 73 OS running on one of those calculators, but it would require a lot more hacking.)

[Galandros]

[critor]

Thank you for your fast replies.


So I'm still trying to send a TI-73 update file to a TI-83+.

[FloppusMaximus]

The OS upgrade file is in a modified Intel Hex format. The first 8 hex digits on each line are metadata (byte count, address, and record type.) You're looking for the line that begins with ":20004000". 0056h is the twenty-third byte after that. In a normal OS upgrade file, that byte is set to FF, and it's followed by A5FFC3.

The last two digits on each line are a checksum; you may have to update the checksum depending on what program you use to send the file to the calculator (I don't remember if TiLP verifies the checksum or not.) The new checksum would be the existing checksum minus 59h, modulo 100h.

[critor]

Thank you very much for explaining me the anatomy of a 8XU/73U file.

I've finished patching the 73U files, and the system can now be transferred to a real TI-83+ without any error.
It boots without any problem.

There is just that big-font-display-bug, but I suppose I would require much more hacking.


By the way, I had to substract 5Bh modulo 100h to the checksum (not 59h).



But anyway thank you very much for your great help!
Having solved that "difficult" question in less than a week, makes me say your forum is great, and you people are great too!
:biggrin:

[TheStorm]

One of the main issues you'll have when tring to run the 73 os on an 83 is the different boot codes. if the os were to call any of the boot code's bcalls it would surly cause issues because it will not preform the function expected.

[FloppusMaximus]

Actually, the TI-73 and TI-83+ boot codes are surprisingly similar. There are 63 boot code entry points on the TI-83+. Of these, the last two (SetAppLimit and BatteryError) don't exist on the TI-73, and where the TI-73 has Load_LFont, the TI-83+ has a second pointer to Load_LFontV. All of the other routines are essentially equivalent. Most of the important stuff, like the code for writing to Flash and reading the calculator certificate, is identical between the two models. The major differences are the aforementioned font issues (in addition to having two pointers to Load_LFontV, the TI-83+ doesn't support the tallLFont flag) and differences in the arrangement of system RAM areas.

If you wanted to make a complete conversion from a TI-73 to a TI-83+ or vice versa, the thing to do would probably be to rewrite, or at least write a wrapper for, each of the boot code routines that behave differently. This wouldn't be as difficult as it sounds; I wrote a replacement boot code a while ago, which works for pretty much everything except installing Flash apps.

[critor]

You're amazing! :)

Do you have any link, so that I can test that boot code on my emulator?
(as I can't modify the TI-83+ boot code...)

[FloppusMaximus]

Well, I never made a website for it or anything. I think this is the latest version.
[attachment=2601:bootfree_11.241.zip]

[TheStorm]

This might be of interest to you as it is the exact opposite of what you are attempting to do. Chameleon I know BrandonW was working on it for quite a while and it was an insane project to attempt but he seems to have done it.

[FloppusMaximus]

Oh, that's very cool. Patching the OS is one thing, but patching it automatically for any version of the boot code? That's quite an accomplishment.

(...and you too can be the proud owner of a Playskool themed TI-83 Plus! )

[magicdanw]

Hey, I just checked on Amazon, and while the cheapest 83+ is $50, the cheapest 73 is less than half that! I don't need either right now, since I already have an 84+SE, but it could be good advice to pass along to anyone looking to buy an 83+ that they can get an equivalent device for under $25 with a bit of hacking.

[brandonw]