Considering nobody with more experience has answered you here I'll venture forth..
There's two viable routes, Retrocomputing and Stack Overflow, which give 9 and 290 search results respectively (including questions and answers reffering the TI-84 model). I list RC first as I would personally consider it a safer option, but your mileage will vary.
Although the numbers suggest there is a larger acceptance for these devices in general on SO, consider further if your intent is to understand why a behaviour occurs from the device's use, or to produce or avoid specific behaviour when coding for the device.
Here are some crucial cues to help decide which destination is most appropriate, depending on your intentions.
Retrocomputing
- How to use or preserve computing equipment that is no longer manufactured or supported by the manufacturer.
- Hardware, including peripherals, and software, including operating systems and applications.
- Are questions about calculators on-topic?
Stack Overflow
- A specific programming problem
- A software algorithm
- Software tools commonly used by programmers
- A practical, answerable problem that is unique to software development
- Not about general computing hardware and software unless directly involving tools used primarily for programming.
- Do we need [texas-instruments]?