Sega Master System / Mark III / Game Gear
The Master System VDP is an extended version of the TMS9918a VDP, with an enhanced mode for "SMS mode" graphics, featuring:
This is known as "mode 4", with "mode 5" appearing on the Genesis. Modes 0-3 are the standard TMS9918a "modes", seen in SG-1000 and SC-3000 software.
Mode 4 is enabled by setting bit 2 of VDP Register 0. This is the mode used by almost all Master System and Game Gear games.
When in mode 4, the TMS9918a mode bits enable extended height modes. One of these is used by some Codemasters games, such as Micro Machines, to enable a 256x224 resolution.