Sega Master System / Mark III / Game Gear
This page is incomplete. You can refer to http://www.smspower.org/maxim/HowToProgram/Palette for additional information.
For the SMS in mode 4, the displayed colours are updated immediately after a write to CRAM.
For the GG in SMS mode 4, the behaviour is the same as an SMS.
For the GG in GG mode, any writes to an even address will go to a latch, and CRAM is unchanged. Any subsequent write to an odd address (even a non-consecutive one) will write two bytes to CRAM to define a single palette entry:
Mode 0,1,2,3 (most commonly mode 2) are legacy MSX1 style compatible video modes. They are used all SG-1000/SC-3000 software. The Mark III, Master System and Game Gear have some form of support for those legacy modes but the palettes are quite off. Unlicensed Korean or Taiwanese conversions of MSX1 games typically use the legacy video modes. Those games would be best played on a SG-1000 or SC-3000 but are modernly commonly experienced on a Master System with the wrong colors.
These are the colours corresponding to the colour indices on an NTSC TMS9918a:
(Colour values are taken from http://bifi.msxnet.org/msxnet/tech/tms9918a.txt)
The SMS VDP converts the TMS9918a colours into approximate equivalents in the SMS's standard 64-colour palette.
|Value||Name||Palette value||SMS Colour
The rightmost column is a comparison to the standard TMS9918a colours. As you can see, they are markedly different (generally, darker).
The Game Gear maps the TMS9918a colours to the corresponding palette indices. However, it does not set the palette, so they are all black (or possibly other values on a console with a BIOS). If a valid palette is written, games are playable; some pirate games were hacked to do this and there is a hacked Tototek menu available that does the same thing.