Motorola 6847

The MC6847 is a video display generator (VDG) first introduced by Motorola and used in the TRS-80 Color Computer, Dragon 32/64, Laser 200, TRS-80 MC-10, NEC PC-6000 series, Acorn Atom, and the APF Imagination Machine among others. It is a relatively simple display generator compared to other display chips of the time. It is capable of displaying text and graphics contained within a roughly square display matrix 256 pixels wide by 192 lines high. It is capable of displaying nine colors: black, green, yellow, blue, red, buff (almost-but-not-quite white), cyan, magenta, and orange. The low display resolution is a necessity of using television sets as display monitors. Making the display wider risked cutting off characters due to overscan. Compressing more dots into the display window would easily exceed the resolution of the television and be useless.

Mitsubishi clone M5C6847
Motorola 6847 Pinout[1]

Video modes
Video ModeResolutionColoursBytes
Alphanumeric Internal 32 × 16 2 512
Alphanumeric External 32 × 16 2 512
Semigraphics 4 64 × 32 8 512
Semigraphics 6 64 × 48 4 512
Color Graphics 1 64 × 64 4 1024
Resolution Graphics 1 128 × 64 1 + Black 1024
Color Graphics 2 128 × 64 4 2048
Resolution Graphics 2 128 × 96 1 + Black 1536
Color Graphics 3 128 × 96 4 3072
Resolution Graphics 3 128 × 192 1 + Black 3072
Color Graphics 6 128 × 192 4 6144
Resolution Graphics 6 256 × 192 1 + Black 6144
gollark: I agree. Although the performance is not great, even in moderately optimized Rust.
gollark: It moves outward from an initial starting location in concentric square "rings", filling each pixel with a randomly chosen adjacent one with some random variation.
gollark: No idea. The original project was called "fractalart", so I kept the name. It generates them using a process which sounds slightly fractal, at least.
gollark: I can tweak a bunch of parameters too.
gollark: I fixed my Rust port of a Haskell program for these. It's very fast.

See also

References
  1. Chip datasheet in PDF
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