TI-83 and Other Calculators

[Moondandy]

The possibility of a TI-83 core was mentioned in another thread, and has come up before, so I thought it would be worth starting a thread for it and discussion about any other calculators.

I imagine a lot of us had to go buy one of these back in the day for school, and likely have them gathering dust in a box somewhere (I've had a look for my old one today but sadly can't find it). I have fond memories of mucking about writing basic code on mine, and one friend trolling another by making a "Chan-agotchi" which as you can imagine was a crude Tamagochi of our mate Chan, where no matter what option you took he would shit himself then die (so pretty accurate to an actual Tamagochi, you just get to the endgame a lot quicker). Fun times.

TI-83.png (243.94 KiB) Viewed 1403 times

I'm quite surprised nobody has taken on this system, or any other old calculators, as under the hook the TI-83 seems to be similar to a lot of the other old Z80 based 8-big PCs we have already.

Technical specifications
CPU: Zilog Z80 CPU, 6 MHz (TI-83, 83+), or 15 MHz (Silver Edition), or Inventec 6S1837 (TI-83+ revision A)[4]
ROM
24 kB ROM (TI-83)
Flash ROM: 512 KB with 163 KB available for user data and programs (83+) or 2 MB (Silver Edition)
RAM: 32 KB RAM with 24 KB available for user data and programs (128 KB on Silver Edition, however the extra 96 KB is not user accessible by default, this extra memory is used in some Applications such as Omnicalc for a RAM recovery feature and a virtual calc)
Display
Text: 16×8 characters (normal font)
Graphics: 96×64 pixels, monochrome 3" LCD
I/O
Link port, 9.6 kbit/s
50 button built-in keypad

Does any of that seem especially difficult to implement? I suspect the trickier parts would be the screen (handheld screens can be esoteric to implement we have seen) and also the controls, as all the keys would need to be mapped which would presumably be a faff - although I expect most people would be using the number keys to play games not COS, TAN, VARS etc.

A quick look sees the BIOS is dumped, and there are software emulators out there already. Someone I was talking to to raised the possible issue that successors to the TI-83 are still in production, and there is an official emulator you can buy, but presumably like other systems there wouldn't be any legal issues as long as no copyright material is included.

Any developer able to weigh in on this one on how viable/complex a core would be and any blockers/pain points I've overlooked?

Are there any other calculators out there that have a load of games and software made for them that are kicking about?

[PistolsAtDawn]

I would like to add to this that the 83 has some terrific games written for it in assembly. They were fast, smooth games (given they were run on a calculator) that sometimes looked less-than-great due to the slow LCD screen. Lots of ghosting. Something that an FPGA might improve or eliminate.

TICalc.org still hosts all of those games to the best of my knowledge.

There are certainly better gaming systems that have yet to be given the FPGA treatment, but I would still say that this would be a worthwhile device family to preserve.

[cmstar0]

There is an FPGA implementation in VHDL with a GPL-3.0 license.

https://github.com/hellux/z80ti-fpga

[Moondandy]

Oh, very interesting, I didn't know about this implementation. I wonder if this could serve as a starting point for someone interested in making a core of it.

[thisisamigaspeaking]

HP 48 (SX) would be interesting as well. It had a few good games. Unfortunately it has a nonstandard CPU.

[cmstar0]

There is also the Casio CFX 9850 Series from the 90's. I actually had this in high school (my parents meant well). Looks like there are some games for it floating around. Though I don't see any FPGA implementations and haven't looked at the specs.

[cmstar0]

Oh, very interesting, I didn't know about this implementation. I wonder if this could serve as a starting point for someone interested in making a core of it.

I posted that link in Discord a while back (I think). IIRC Birdy seemed slightly interested, but I don't think it went anywhere. I am also very likely misremembering.

[cmstar0]

And one rabbit hole later, here is some useful info and links if anyone likes a challenge for the Casio calc:

https://threadreaderapp.com/thread/1510 ... 83021.html

[thisisamigaspeaking]

639 HP 48 games: https://www.hpcalc.org/hp48/games/

[Newsdee]

The HP48 had a great library of grayscale games, which is amazing for a calculator that only has a b&w display. It helps that lots of owmers were engineering majors who wanted to impress their peers

(grayscale was done by refreshing the screen quickly, so it was a bit flickery, but usable)

[PistolsAtDawn]

The HP48 had a great library of grayscale games, which is amazing for a calculator that only has a b&w display. It helps that lots of owmers were engineering majors who wanted to impress their peers

(grayscale was done by refreshing the screen quickly, so it was a bit flickery, but usable)

The TI-83 series used the same technique for greyscale (I think the Game Boy did too). It was really impressive to me given I bought the calculator for school not for gaming, but guess what I did with it most?

[Newsdee]

The TI-83 series used the same technique for greyscale (I think the Game Boy did too). It was really impressive to me given I bought the calculator for school not for gaming, but guess what I did with it most?

Before I got my HP48 we were so bored we even made (bad) games on a Casio

A core of any of these would be neat; although I guess it would represent a lot of work for just playing a handful of games.