TI runs all its low-level calculator stuff on Z80 emulators which are then helpfully run by whatever actual chip they are putting in the calculators these days.
Nope; with one exception, the Z80-family calculators are still run by real, bona-fide Z80s (or, in the case of the new TI-84 Plus CE, an eZ80).
(That "one exception" was the TI-84 Keyboard for the original Nspire, which did run the 84's firmware in a Z80 emulator on the Nspire's ARM processor.)
