TI TMS9918

Texas Instruments · 1979 · Texas Instruments TMS9918 Video Display Controller

A 1979 video chip that popularised hardware sprites and became one of the most widely shared graphics designs of the 8-bit era — the ColecoVision, MSX and SG-1000 all used it, and Sega's Master System chip grew from it.

Texas Instruments introduced the TMS9918 in 1979 for its TI-99/4 home computer. It was a self-contained video display controller with its own 16 KB of dedicated video RAM, producing a 256 by 192 image from a palette of 15 colours plus transparent. Karl Guttag was one of its designers. The chip's most influential feature was its support for hardware sprites: up to 32 movable objects that the chip drew over the background without the CPU having to redraw them. The limitation was that only four sprites could appear on any single scanline; a fifth on the same line would not be drawn, so games either avoided lining sprites up horizontally or flickered them. The VIC-II designers at MOS Technology later took the TMS9918's sprite idea as one of their inspirations. Because it was available as an off-the-shelf part, the TMS9918 and its TMS9918A revision appeared across many machines from different companies: the ColecoVision, Sega's SG-1000 console, the Memotech MTX computers and the MSX standard, which made it effectively the shared graphics chip of a whole family of Japanese and European computers. Its descendants extended that reach. Yamaha's V9938 succeeded it in the MSX2, and the video processor of Sega's Master System was an evolution of the TMS9918 design.