23 Jun
1997
23 Jun
'97
1:59 p.m.
It was thus said that the Great Marvin once stated:
SUPRDAVE(a)aol.com wrote:
It supports two modes that CGA doesn't: 320x200 16 color and 640x200 4
color, in addition to the other CGA modes. The 320x200 16 mode isn't quite
EGA in layout though - the palette registers only support 2 bits of red, 2
of green and 2 of blue, and the layout of the pixels follows (more or less)
the CGA standard than the EGA bitplanes.
Each byte held two pixels (four bits per pixel) and the memory layout was:
0x0000: 2000 bytes of screen information, each line 40 bytes, lines
evenly divisible by 0
0x2000: 2000 bytes of screen information, each line 40 bytes,
line % 4 == 1
0x4000: 2000 bytes of screen information, each line 40 bytes,
line % 4 == 2
0x6000: 2000 bytes of screen information, each line 40 bytes,
line % 4 == 3
The 620x200 4 color mode was similarly laid (layed?) out, only there were
four pixels per byte (2 bits per pixel).
-spc (Although with proper programming, the CGA could support 160x100
16 colors (or was it 160x200?))
standard cga monitor into the back. if anyone's interested, i could post the
pinouts of the dongle so you can use cga. the last hamfest i went to have
As I recall, the PC Jr. does not use CGA but rather EGA. Something in
the back of my mind says that the REAL PC Jr. monitor is not quite EGA
but definetely better than CGA.