Hnnnng. I cannot wait until I get my CSE

This is looking awesome, great work!

If it's still a bit active, is there a way to make it work with the TI-83 Premium CE ?

I believe that a properly optimized emulator could run significantly faster on the eZ80 units. OS and flash app performance are crippled by an insane number of wait states on flash reads. RAM, however, is less crippled, and there exists the potential to get better MIPS from RAM programs than the old Z80 series could provide. So an emulator that runs entirely in RAM might be able to be much faster, though it would be limited in the size of ROMs it could handle (but at least 256 K).

It's kind of technical, but basically, the eZ80 runs at 48 MHz (the TI-83+SE, TI-84+/SE, and TI-84+CSE ran at 15 MHz), but the bus feeding data to and from the CPU is so slow that the CPU spends about---I'm taking a guess here---80 % of its time idle, waiting for data. Essentially, the benefits of a much faster CPU clock speed are entirely negated by the awful bus performance for code running from flash. The eZ80 models still get a little bit better performance because the eZ80 is also tightly pipelined, such that its performance is limited by the external bus performance; the Z80, by contrast, is limited by both its lack of pipelining and slow ALU. The upshot is that on the rare occasion the eZ80 does get data, it processes it in fewer clock cycles than the Z80, so even with a much slower bus, it can still process data a bit faster. As a bonus, C code on the eZ80 gets a relative boost to C code on the Z80 because the eZ80 is much far efficient with stack frames.

RAM is subject to less than half the wait states of flash, which is partly why display operations are so much faster. Overall, programs running from RAM might be twice as fast as a flash-based apps, which is good news for us, because we don't have an app signing key anyway.

The screen interface is entirely different between the CE and CSE, and display performance is subject to a completely different set of performance rules. The Z80 is ridiculously slow when using the IN and OUT instructions, which were used for talking to the LCD. The eZ80 is far faster with IN and OUT, but TI instead decided to use a memory-mapped display, which is great for some purposes, but actually slower for drawing sprites. Which is odd, because sprite-like drawing is most of what the calculator needs anyway. The memory-mapped display requires a lot of pointer arithmetic, so it's a good thing the eZ80 is considerably faster at pointer arithmetic. The memory-mapped display also uses a DMA that steals about 10 % of the bus bandwidth. Good news, though: the new display supports palletized modes, which use fractionally less bus bandwidth depending on the bits-per-pixel setting (e.g. 4 bits-per-pixel uses a quarter of the bandwidth that the normal 16 bits-per-pixel mode uses).

Somebody should probably put all of that on Wiki or something other than WikiTI, which is only read by programmers.