Realtek RT 3106    -  Upto 1 Mbyte.

RTG3105  100pin
RTG3106



3CEh index 0Ah (R/W):

3CEh index 0Bh (R/W):
bit 0-1  Divide the Video Dot Clock by: 0: 1, 1: 1.5, 2: 2, 3: 4

3CEh index 0Ch (R/W):
bit   2  Always set ??
      4  If set doubles the number of pixels in a "character clock"
           Pixels per character clock:
                                  clear         set
            16color modes           8           16
           256color modes           4            8
         Also there are two clock pulses per pixel.
      5  Clock Select bit 2. Bits 0-1 are in 3C2h/3CCh bits 2-3.
      6  ??


3CEh index 0Fh (R/W): Extended Function.
bit   2  Single/Dual bank.
         If set 3D6h is the read bank number and 3D7h is the write bank
         number, if clear 3D7h is used for both read and write operations.

3d4h index 19h (R/W):
bit   0  Interlace enabled if set. If set the display offset in 3d4h index 13h
         is the number for two scanlines, rather than one.
      1  Enable memory beyond 64K (256colors)
      4  Display Start Address bit 16.
      5  Enables display to cross 256K boundary if set
      6  Display Start Address bit 17.
      7  Enables display to cross 512K boundary if set

3d4h index 1Ah:
bit 6-7  Chip version.
           0 = Version 0  (RTG3103 ?)
           1 = Version 1  (RTG31030?/RTG3105)
           2 = Version 2  (RTG3106)
           3 = Version x ??

3d4h index 1Eh:
bit 0-1  Video Ram. If Chip version =0: 0=256k, 1=512k, 2=768k and 3=1MB
                    If chip version >0: 0=256k, 1=512k, 2=1MB and 3=2MB.
      2
    4-6
      7  Must be set to access the extended CRTC registers ????

3D4h index 1Fh (R/W):
bit 0-1  Emulation mode: 0=VGA, 1=EGA, 2=CGA, 3=MDA
    2-5

3D6h (R/W): Bank register
bit 0-3  64k Bank register   (Read bank if 3CEh index Fh bit 2 set)

3D7h (R/W): Bank Register
bit 0-3  64k bank number.    (Write/single bank)


Test for Realtek Chip:

if testinx2(base,$1F,$3F) and tstrg($3D6,$F) and tstrg($3D7,$F) then
  case rdinx(base,$1A) shr 6 of
    0:Realtek RT3103
    1:Realtek RT3105
    2:Realtek RT3106
  end;


  Video modes:

    18h  T     80   30  16  (9x16)
    19h  T     80   43  16  (9x11)
    1Ah  T     80   60  16  (9x8)
    1Bh  T    132   25  16  (9x14)
    1Ch  T    132   30  16  (9x16)
    1Dh  T    132   43  16  (9x11)
    1Eh  T    132   60  16  (9x8)
    1Fh  G    800  600  16  PL4
    20h  G    960  720  16  PL4
    21h  G   1024  768  16  PL4
    22h  G    768 1024  16  PL4
    23h  G   1024  768   4  PL2
    24h  G    512  512 256  P8
    25h  G    640  400 256  P8
    26h  G    640  480 256  P8
    27h  G    800  600 256  P8
    28h  G   1024  768 256  P8
    29h  G   1024 1024 256  P8
    2Ah  G   1280 1024  16  PL4
    38h  G    320  200 64K  P16
    39h  G    512  512 64K  P16
    3Ah  G    640  400 64K  P16
    3Bh  G    640  480 64K  P16
    3Ch  G    800  600 64K  P16

----------105F00------------------
INT 10 - VIDEO - Realtek VGA - RETURN CHIP VERSION
        AX = 5F00h
Return: AH = 00h if successful
        AL = Chip version
               00h  RTG3103 ?
               01h  RTG31030/RTG3105
               02h  RTG3106 ?
               3Fh  Not a Realtek chip
----------105F01------------------
INT 10 - VIDEO - Realtek VGA - GET RTVGA BIOS STRING
        AX = 5F01h
        ES:DI -> buffer to receive BIOS ID string
Return: AL = 00h if successful
        ES:DI -> buffer with zero terminated BIOS ID string
----------105F02------------------
INT 10 - VIDEO - Realtek VGA - GET VIDEO MEMORY SIZE
        AX = 5F02h
Return: AH = 00h if successful
        AL = Memory size. 0: 256K, 1: 512K, 2: 768K, 3: 1024K
----------105F03------------------
INT 10 - VIDEO - Realtek VGA - SET ??
        AX = 5F03h
        BL = 0-3 ??
Return: AH = 00h if successful