commandblockguy wrote:
There's no real benefit to having an entirely custom bootcode over a slightly patched TI bootcode, at least in terms of custom OSes. It's like nine bytes difference to disable all OS validation checks. You also couldn't load any OS you wanted - most operating systems rely on processor features like virtual address spaces to run processes, so you could probably only run OSes specifically designed for embedded systems.


So does this mean stuff like Alpine Linux or really smally versions of linux could run with some hacking?
fm'latghor wrote:
commandblockguy wrote:
There's no real benefit to having an entirely custom bootcode over a slightly patched TI bootcode, at least in terms of custom OSes. It's like nine bytes difference to disable all OS validation checks. You also couldn't load any OS you wanted - most operating systems rely on processor features like virtual address spaces to run processes, so you could probably only run OSes specifically designed for embedded systems.


So does this mean stuff like Alpine Linux or really smally versions of linux could run with some hacking?



Definitely not Linux. However, I bet some Unix-like operating system can be made. As for Linux however, the smallest version of Linux i've heard of is Tiny Core Linux, and that's 12 MB.
As far as hardware specs are concerned, only the most expensive graphing calculator models can run real Linux distros:
* the Nspire CX I & II, and the HP Prime G1 & G2, have enough raw power (all ARM processors), RAM and Flash memory;
* the older monochrome Nspires (Clickpad, Touchpad), also ARM-based, have slower processors, less RAM and less Flash. Linux had been ported, but it's not really advisable to run it.
All of these models have 320x240 screens, so desktop environments and GUI applications aren't usable in practice, though they have been shown to work.

The jury's still out on the Casio fx-CG50 (Graph 90+E in France). All three of the 8 MB of RAM, the 32 MB of Flash and the SH ISA would be annoying, so if some user-space programs can be run by modern Linux on that setup, then they can only be quite minimal.

On the lesser graphing calculator series, no dice. Improper processors, highly insufficient amounts of RAM and Flash memory, etc.
*Bump
How is the project going? Razz
Beck is currently trying to dissociate the quantum flux of the inverse gravitational capacitor within 300-400 terra-flopping Magikarps of the distributed sinographic cosine algorithmic predictive quantitative analysis protocol.


jk. But seriously though, he's still working on it, in between spurts of helping me with a not-so-secret project.
Alvajoy:
Renamed Open-CE to Noti, because the name OpenCE is used by another software.
[removed]
[removed]
Well the CE died for a worthy cause. Do you have any idea what went wrong?

EDIT: Nice work on getting this far though, this is a great project.
beckadamtheinventor wrote:
Long story short, it did not work. Calc is bricked and will likely never work again. Thankfully this is only one of the three I own. DO NOT TRY THIS.

Shouldn't it be possible to reprogram the flash chip itself, either in-place or desoldered into a dedicated programmer? It would require some hardware and time, but I bet it's far cheaper than buying TI calculators in bulk.
boricj wrote:
beckadamtheinventor wrote:
Long story short, it did not work. Calc is bricked and will likely never work again. Thankfully this is only one of the three I own. DO NOT TRY THIS.

Shouldn't it be possible to reprogram the flash chip itself, either in-place or desoldered into a dedicated programmer? It would require some hardware and time, but I bet it's far cheaper than buying TI calculators in bulk.

With a steady hand and soldering tools, one could get the flash chip off, but it has like 40 pins. Sad
beckadamtheinventor wrote:
With a steady hand and soldering tools, one could get the flash chip off, but it has like 40 pins. Sad

Then it would be a better idea to prototype using models containing a Flash chip with SOIC-8 packaging since it'd be much easier to resurrect dead calculators.
With a steady hand and soldering tools, one could get the flash chip off, but it has like 40 pins. Sad[/quote]

Is there an emulator that you could use to try out the code? Haven't worked with emulators myself, but if they require a ROM, it makes sense to me it would be reasonable.

Of course I could be completely wrong, wouldn't be the first time.
byates wrote:

boricj wrote:
With a steady hand and soldering tools, one could get the flash chip off, but it has like 40 pins. Sad


Is there an emulator that you could use to try out the code? Haven't worked with emulators myself, but if they require a ROM, it makes sense to me it would be reasonable.

Of course I could be completely wrong, wouldn't be the first time.

There is in fact an emulator Smile
CEmu
Build it by running build.sh (or build.bat on Windows) assuming you have the C toolchain / fasmg installed. The ROM will be found as bin/NOTI.rom

and yeah... that chip aint getting reflashed any time soon.
Noti-eZ80 now has the ability to load an OS from a FAT32 formatted USB drive! This will only work in a specific branch of CEmu, that you have to build yourself, and run on Linux. (with super user USB privileges or super user) Sorry to Mac and Windows users, your OS sucks and does not support the required access

My original warning of don’t install this still stands. DO NOT install this on hardware!
Very nice! I wonder if virtual USB peripherals such as a MSD can be incorporated into CEmu as opposed to relying on hardware passthrough?
Noti-ez80 now has a partial implementation of sprintf. %d, %u, %c, %x, %X, %o, and %s should all work now. However none of the third/fourth character combos are implemented as of yet.
How long do you think it'll take to reach the ability to reflash TI-OS? So that it might be tried safely on a real calculator?
lennartVH01 wrote:
How long do you think it'll take to reach the ability to reflash TI-OS? So that it might be tried safely on a real calculator?


noti-ez80 will not likely ever be safely installable on physical hardware. Even if I can get it to work safely I still would not reccomend it. There is really no point to having a fully custom bootloader on physical hardware, aside from boot menus/recovery modes; which can be accomplished without completely reflashing the bootcode.
  
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