First post, by bakemono
This is one of those weird things that I can't help be curious about...
MCGA supports CGA graphic modes (and presumably they get scan-doubled to VGA frequency). It has text modes with 8x16 character (can it also do 8x8?). And it can do two VGA graphic modes: 640x480x1bpp, and 320x200x8bpp (mode 13h).
That's kind of a wild combination of modes there, so it seems likely that it must have its fair share of configuration registers at the hardware level, similar to what VGA has. On VGA, this flexibility gave rise to mode X and various non-standard resolutions/scanrates. So what about MCGA?
On VGA 640x480x4bpp the memory is divided into four planes, and this resolution uses most of each plane. BTW, I recall reading that EGA cards with 64KB could do 640x350 restricted to two planes. MCGA has 64KB, so does that mean it could also do two planes? Like 640x400x2bpp? Or is it limited to one? Maybe scan-doubling could be switched off in CGA mode and produce 320x400x2bpp?