Then request your CSE that is powerd by four AAAs, and if they don't give it to you sew 'em

Looking at the PCB, it seems that the TI-84+CSE was originally intended to support running on AAAs. The PCB still has the same pads at the bottom for accepting power from AAAs, the circuit it connects to is populated, and the battery compartment is tall enough, but it's not quite thick enough. I think that could be solved with a little bit of dremeling. TI added thick plastic (maybe one or two millimeters) between the battery and the PCB which I believe accounts for the difference. There's definitely hardware modding potential there. I think TI should have left in the ability to run it on AAAs as a backup solution.

EDIT: I'm silly. The pads I'm talking about are where the charging bay connectors connect. The size of the battery bay is simply because TI's engineers didn't feel like changing the CAD design. Nevertheless, the modding potential remains.

MSD8X will NOT work on the new TI-84+SEs. They do not have the extra RAM pages.

Attached is USB8X 0.13 and MSD8X 0.96.

MSD8X requires the extra RAM pages, yes. However, USB8X itself doesn't. MSD8X uses them for buffering data.

I don't think anybody's said this explicitly yet: The TI-84+ series ASICs do not support the 512 K flash chip TI used for the TI-83+. Specifically, the (easily disabled) circuits that are supposed to censor the cryptographic certificate and prevent the boot code from being modified only support mapping 1, 2, 4, and 8 MB flash chips.

As suggested above, TI probably wants to retain the TI-83 Plus name that has remained the most popular graphing calculator for over a decade. Getting rid of the traditional TI-83 Plus hardware also lets them simplify manufacturing. It also lets them bring the joys (or lack thereof) of USB linking to the TI-83 Plus market. Perhaps TI will drop the TI-84 Plus non-SE, since the non-SE is now the same as the TI-83 Plus. And with any luck, TI will offer the new TI-83 Plus at the same price point as the old TI-83 Plus, a move they really should have made five years ago.

Dropping the B&W screen models seems like a bad idea for one simple reason. When was the last time you changed your calculator's batteries? The TI-84 Plus line is quite power efficient. The fact that students normally don't need to change or recharge their calculator every week is a major plus. Also, teachers giving exams are more likely to be able to provide a spare set of AAAs than a spare lithium-ion battery.

You can indeed erase the border. I'm not sure how often the OS redraws it, but it actually isn't very often because TI actually did try a tiny bit of optimization. The run indicator will come back, of course, unless the assembly program also turns it off.

Wait, so the ASIC actually divides the clock for cpu speeds 2 and 3 if you replace some 0 ohm resistors?

Uh, no, not 0 ohm. For 20 and MHz mode, you need ca. 2.5 and 2.9 kOhm resistors; the resistance controls the precise frequency.

Any idea if it's possible to do this with a TA1 ASIC?

No, not as of yet. I doubt it though; part of the purpose of the TA1 was to reduce pin count. (Pins are like a penny a piece.)

I once replaced the crystal in my M revision 84+SE with a faster one but the lcd didn't update at all, current draw indicated the calc was working though.

Replacing the crystal would definitely not make your calculator run faster. The 32768 Hz crystal has nothing to do with CPU speed; it's used for timing purposes only. The 48 MHz one also has nothing to do with CPU speed; it's used exclusively with the USB controller.

Why would TI have support for ~25 mhz in the ASIC and not enable it by not populating some resistors?

It may have to do with saving battery power, although with the TI-84+CSE, the CPU plays pretty much no role is overall power usage. (The backlight consumes probably 95% of all power.) They may also have had concerns about whether the flash chip could handle such speeds, although it's probably a moot point with today's chips. The most likely answer is that TI is staffed by intelligent engineers and idiotic, bureaucratic managers who wouldn't give you the time of day unless you paid them ten thousand dollars and signed an NDA.

I'm retracting my claims about IM 2. I ported the program to my new TI-84+CSE (which has the same ASIC) and it AAARGHs!s.