A home computer created by Texas Instruments and released in 1981. It was the first home console to feature a 16-bit processor and included a prototype plug-and-play serial bus similar to what would become known as USB.


The TI99/4A shipped on June 12, 1981 with a price tag of $525 and was a successor to the less popular TI99/4 which was released two years earlier at double the price. The TI99/4A made several improvements over its predecessor including added graphics capabilities and lowercase letters, though it was still just the standard ACSII output but smaller.
The TI99/4A is best known for being the first home console to include a 16-bit processor, a full 10 years before the SNES. The system was however limited by the system RAM which created a bottleneck down to 256 bytes.  It also offered full Plug and Play capabilities that included not only system peripherals but printers and other home computing devices. Using a prototype high speed serial bus it could be seen as a prototype to today's USB plug-n-play hot-swappable systems.

Technical Specifications

  • CPU: TI TMS9900, 3.0 MHz, 16-bit
  • Memory: 16KB VDP RAM (expandable to 192 KB with the use of YAMAHA V9938)
  • Video: TI TMS9918A VDP
    • 32 single-color sprites 
    • 16 fixed colors 
    • Text mode: 40×24 characters
    • Graphics mode: 32×24 characters
    • Bitmap mode: 256×192 pixels
    • Multicolor mode: 64×48 pixels
  • Sound: TI TMS9919, later SN94624
    • 3 voices, 1 noise (white or periodic)
    • Voices generate square waves from 110 Hz to approximately 115 kHz
    • Console ROM includes interrupt-driven music list playback

TI-99/4A games