I'm new to Cemetech and only somewhat familiar with phpBB, so forgive me if I mess anything up! Hello ^_^

I recently got a TI-84 Plus CE Python edition, and was given a complimentary 4-year subscription to the TI-84 Plus CE online calculator. I've gotten a lot of use out of my physical calculator, but the online calculator has been intriguing me a lot more. I can see a lot of good use cases for it - I'm limited to a Chromebook in school, and being able to show the teacher (and my friends) what I'm doing on a bigger screen would be awesome! It has a lot of limitations, though, which... only intrigues me more. I want to try to understand how this thing works.

Here's some of what I've found!

When you first start the online calculator (or reset it), it boots with the "RAM Cleared" screen.


This made me wonder about any self-test results, so I did! I immediately thought I was going crazy, as all the self-test text was highlighted red instead of green.




I learned that this was because none of the tests had actually been run. I attempted to run the "RAM / SHIP" test, but it hung on the "RAM test - running..." screen for more than a few minutes, so I gave up.


I also plugged in my physical calculator and tried the "USB A>B B>A" test just for fun, but it understandably didn't work. In the end, I was able to successfully run every test except for "RAM / SHIP" and "USB A>B B>A".


Something that caught me off-guard was running the "FLASH/Prot" test. On my physical calculator, this shows that something (the flash memory?) is locked, along with some other stuff. Here, I get... something else in a very different layout from what I see on my physical calculator.


My only reference is my physical calculator, so I don't know if this is special or if this is something you can actually see on a physical calculator. If anyone else has information, I'd really appreciate knowing more about that! Tari shared that this is emulating parallel flash. My calculator uses serial flash, which explains the different screens.

I have a lot of hopes for this project - maybe I (or someone else) will be able to import applications into the online calculator...? Even if not, it'll be fun to document.

TI's SmartView emulator doesn't fully emulate the calculator's hardware - several OS calls check if the calculator is being emulated, and if so request the emulator to do certain operations rather than accessing the hardware through the usual interface. So, a lot of "non-user-accessible" functionality like the self-test screen and things that you can only do using assembly don't work quite right.

If you want a more accurate emulator, you can use TI Planet's project builder, which contains the CEmu emulator core compiled for WebAssembly.

Since you're focused on the self-test, you might want to see previous discussion of the CE self-test. The sector protection display you show here is the same as that discussion's version (aside from different reported protected sectors). I believe the code for this self-test lives in the boot code, so if it's different on your physical calculator that might indicate you've got a different boot code version.

LogicalJoe claimed in chat that the self-test code is part of the OS and not the boot code as I had guessed, and that it behaves differently depending on whether the calculator has parallel or serial flash; OSes since 5.3.6.0018 display something like this for the flash protection test when running on a calculator with serial flash:

Serial flash has been used in new CEs since around 2019 (I assume somebody else could tell you exactly what hardware revision made that change, but I'm not plugged into that scene enough to say), so if your physical calculator is reasonably new then we'd expect you to see that kind of screen.

Since the web-based emulator TI provide is almost certainly a version of SmartView which is known to emulate parallel flash, the result you shared is consistent with expectations.

This is pretty much what I expected, but that's also exactly what I'd be interested in learning more about.


I'll take a look at that - thanks!


I'll edit my post to reflect that. Thank you!