There are 32 of these registers (xx = 00-31) and together with the banking
bits they address the 256 locations in the color palette. There are
actually two sets of color regs, selection of which is controlled by
the LOCT reg bit. When LOCT = 0 the 4 MSB of red, green and blue
video data are selected along with the T bit for genlocks the low
order set of registers is also selected as well, so that the 4 bits-
values are automatically extended to 8 bits.This provides
compatibility with old software. If the full range of palette values
are desired, then LOCT can be set high and independent values for
the 4 LSB of red, green and blue can be written. The low order
color registers do not contain a transparency (T) bit.
The table below shows the color register bit usage.
T = TRANSPARENCY,
R = RED,
G = GREEN,
B = BLUE
T bit of COLOR00 thru COLOR31 sets ZD_pin HI, When that color is
selected in all video modes.