MV452    Pro Graphics 1024
 MV451?   Pro Graphics 1280

 MV462    DAC for the 1024


The Mediavision Pro Graphics 1024 uses two registers located at one of
these locations: 538h/539h, E88h/E89h, F48h/F49h, 60Ch/60Dh, 148h/149h.


279h (W):
bit 0-7  The base register (REG) is programmed by writing the following
         38 byte sequence to this register:
          00h 00h B2h D9h ECh 76h BBh 5Dh AEh D7h 6Bh 35h 9Ah CDh E6h F3h
          79h BCh 5Eh AFh 57h 2Bh 15h 8Ah C5h E2h F1h F8h 7Ch 3Eh 9Fh 4Fh
          27h 13h  <high>  <low>  00h 00h
         Where <high> and <low> are the high and low byte of the base
         register (REG). 538h, E88h, F48h, 60Ch and 148h are known to work.
NB: is this the unlock sequence instead ??

REG (R/W):  Index
bit 0-?  (W) Selects the indexed register to read or write at REG+1
         (R) 38h if the base register is programmed, FFh if not

REG index  0 ():
bit 3-7  (R) Always 7

REG index  1 (R/W):
bit 0-1  ??

REG index  2 (R/W):
bit 0-7  ??

REG index  5 (R/W):
bit   4  ??
      5  ??
      7  ??

REG index  8 (R/W):

REG index  9 (R/W):
bit   0  ??
      2  ??
      3  ??



Memory mapped registers:

M+000h

M+002h
bit 0-3
      4
      6