The TI-99/4A is the home computer from Texas Instruments, released in June 1981 as a revision of the 1979 TI-99/4 — the main change being a proper keyboard in place of the original calculator-style membrane. It is the first home computer built around a 16-bit processor, the TMS9900, an architecture inherited from the company's minicomputers.
Texas Instruments made its own chips, and the TI-99/4A spread them widely: its TMS9918A video chip and its sound generator later turned up in the ColecoVision, the SG-1000 and the MSX machines. The computer became famous for its speech synthesis module, given away with purchases for a while, and for an American advertising campaign fronted by Bill Cosby.
Its story ends abruptly: the price war waged by Commodore with the VIC-20 and then the C64 pushed Texas Instruments into selling at a loss, and the company left the home computer market in October 1983. Its library remains endearing, with Parsec, TI Invaders, Munch Man, Alpiner and Tunnels of Doom.
It is the only emulator offered for this system, and it is available on every board, from the Raspberry Pi 3 and Pi Zero 2 up to the PC. As it is not a libretro core, netplay and softpatching are not available, and RetroAchievements are not supported. CRT output is handled.
A keyboard is mandatory on this system: the TI-99/4A home screen is navigated from the keyboard and most programs require one. Recalbox still ships a pad-to-keyboard file out of the box, which maps pad buttons to keys — see the TI-99/4A guide.
The system cartridge is mandatory: without it, nothing boots. The two other files add optional features of the real machine.
| File name | Description | MD5 | Emulators |
|---|---|---|---|
ti994a/TI-994A.ctg |
System cartridge — the console ROMs (mandatory) | 412ecbf991edcb68edd0e76c2caa4a59 | ti99sim |
ti994a/spchrom.bin |
Speech synthesis module ROM (optional) | 7adcaf64272248f7a7161cfc02fd5b3f | ti99sim |
ti994a/ti-disk.ctg |
Disk controller, the machine's disk operating system (optional) | 04714f43347cefb2a051a77116344b3f | ti99sim |
Place your BIOS files like this:
/recalbox/share/bios/ti994a/
├── TI-994A.ctg
├── spchrom.bin
└── ti-disk.ctg
The name
TI-994A.ctgis uppercase, with a dash and no slash. The BIOS checker will tell you what is missing.
Put your games in:
/recalbox/share/roms/ti994a/
Accepted extension: .ctg
.ctg is the cartridge format specific to ti99sim: it packs the various ROM and GROM chips of a retail cartridge into a single file. Dumps distributed in other shapes therefore have to be converted to .ctg before being copied into the roms folder. No other extension is recognised by this system, archives included.
The TI-99/4A guide details the mapping between pad buttons and keyboard keys, which is very handy to navigate the machine's home screen.