Category:84PCSE:General Hardware Information

The TI-84+CSE uses the same ASIC as the TI-84+/SE, so the hardware ports are mostly the same. Ports 0E and 0F have always been functional, but they were previously useless; they are now used to swap flash. Port 21 now normally hold 02. Ports 10h and 11h are totally different. See also.

WARNING: The TI-84+CSE does not appear to have a hardware-based low-voltage shutdown on the ASIC. As a result, it appears that an assembly program can run the battery all the way down and render the battery useless. If your software overrides the OS interrupt handler, you must check the battery charge level yourself, or have some other way to prevent the battery from being run down.

A quick look at the ASIC PCB photos shows that the LCD backlight dimmer (CAT4004A or work-alike) is connected directly to the battery. Its low-voltage shutdown threshold is 2.0 V, by which point the battery is long past unrecoverable. There could be a hidden circuit that overrides the dimming control pin (and thereby turn the backlight off), but I doubt it.