Commands can be sent by the computer to this fake Titanium through the OUT endpoint, but the TI-Nspire never responds. When connected to a computer linking software such as TI-Connect or TiLP, a TI-89 Titanium is strangely advertised by the USB descriptors (fixed in versions 2.44+). Texas Instruments has probably preferred to integrate a DBUS to the snap-in TI-84 Plus Silver Edition keypad and emulate it rather than to waste time on USB emulation. The TI-84 Plus/SE (and 89 Titanium) USB controller has a quite complicated port interface, and the TI-Nspire probably uses a different controller. The USB ports are not emulated, and events on the USB bus are not propagated to the memory-mapped port according to Calcsys and usb8x's USBTools and PortMon. One glitch known to happen with the LCD is that after the processor halts in low-power mode (turning the LCD off) and the LCD is turned back on, the contrast is reset to a particular (most likely incorrect) level. On Nspires with the version 2 operating system (2.53MP in 84+ emulation mode) the border is not filled with gray and remains white. The unused pixels outside this area are filled with gray. The TI-Nspire displays the TI-84+SE screen in a 288x192 pixel area, each 3x3 block of Nspire pixels corresponding to one TI-84+SE pixel. The emulated Z80 has several special opcodes, which control functions such as linking, Flash reading and writing, and lock/unlock the TI-84 Plus Silver Edition keypad.
These applications are restored on a full reset from the back of the case.
The TI-84 Plus Silver Edition ROM archive memory is set up with preinstalled Flash applications, but they can be deleted from the current memory image. Some features are disabled in the Nspire versions: the key combo for the self-test doesn't work, and the TI-84 Plus Silver Edition OS can't be upgraded (an error is returned by the computer link software). The version of the boot code is 1.02, according to 0x400F of ROM page 7F (see WikiTI). Starting with version 2.42 (and continued with 2.44 and 2.46), even-numbered versions of the TI-84 Plus Silver Edition OS are used while the latest version available for the real TI-84 Plus Silver Edition is 2.43. The speed is roughly the same, and the RAM and archive memory have equivalent sizes (the whole memory of the TI-Nspire is not visible from the emulated TI-84 Plus Silver Edition). Fortunately a ROM image of the emulated TI-84 Plus can be dumped through the DBUS with standard tools such as TiLP.ĭo not expect the emulated TI-84 Plus Silver Edition to offer more features than the real one. The OS code is encrypted and perhaps compressed with the rest of the TI-Nspire OS code in certificate field 8070. The archive memory of the TI-84 Plus Silver Edition is integrated to the TI-Nspire OS as 64KB files in a PK-Zip file (see the OS upgrade file format).
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