6845
CRT controller
19891016/wjvg

0   w ...nnnnn  register select
1  rw nnnnnnnn  register read/write

registers:

00  w nnnnnnnn  horizontal total characters (-1)
01  w nnnnnnnn  horizontal displayed characters
02  w nnnnnnnn  horizontal sync character position (-1)
03  w nnnn....  vertical sync width rasters
    w ....nnnn  horizontal sync width characters
04  w .nnnnnnn  vertical total lines
05  w ...nnnnn  vertical total adjust rasters
06  w .nnnnnnn  vertical displayed lines
07  w .nnnnnnn  vertical sync position line (-1)
08  w nn......  skew of CUDISP output signal
    w ..nn....  skew of DISPTMG output signal
    w ......n1  video mode
    w .......1  interlace sync mode
09  w ...nnnnn  maximum raster address
0a  w .n......  cursor blink
    w ..n.....  cursor blink period
    w ...nnnnn  cursor start address
0b  w ...nnnnn  cursor end address
0c rw ..nnnnnn  start address (h)
0d rw nnnnnnnn  start address (l)
0e rw ..nnnnnn  cursor (h)
0f rw nnnnnnnn  cursor (l)
10 r  ..nnnnnn  light pen (h)
11 r  nnnnnnnn  light pen (l)

end