video7.txt

比较详尽的VGA端口寄存器的文档

3C4h index F5h (R/W): Foreground/Background Pattern
bit 0-7

3C4h index F6h (R/W):  1MB RAM Bank Select
bit 0-1  Write Bank no bit 2-3 if 256 color, bit 0-1 else.
    2-3  Read Bank no bit 2-3 if 256 color, bit 0-1 else.
    4-5  CRTC Bank (Address bit 16-17)
      6  Display address Wraps Around at bank boundary if clear
      7  Split Screen Wraps around at bank boundary if clear

3C4h index F7h (R/W):  Switch Readback
bit 0-7  Switch positions as read by the last write to the Switch
         Strobe Register (3C4h index EAh)

3C4h index F8h (R/W):  Extended Clock Control
bit   0  Clock select bit 3. Bits 0-2 are in index A4h bits 2-4.
    5-7  Clock Source: See index A4h bits 2-4.
Note: depending on mode and other bits in this register other
      values may be selected.

3C4h index F9h (R/W):  Page Select
bit   0  bit 16 of Video Memory Address. (Only needed if in a
         256 color mode, and 3C4h index FCh bit 1-2 = 1).

3C4h index FAh (R/W):  Extended Foreground Color
bit 0-3  Foreground expansion color.
         Bit 0 is written to plane 0 et cetera.

3C4h index FBh (R/W):  Extended Background Color
bit 0-3  Background expansion color
         Bit 0 is written to plane 0 et cetera.

3C4h index FCh (R/W):  Compatibility Control
bit   0  Enable Extended Attribute functions if set
         Extended attributes allows underlining using a mask
         in plane 3 for each character.
      1  256-Color 64K/128K paging Select. 128K pages if set, 64K pages else.
         Only active if bit 2 set
      2  256-Color Paging Enabled if set.
    3-4  Reserved.
      5  Enables sequential chain4 mode if set ??
      6  Reserved.
      7  If set allows enabling VGA via 102h bit 0 or 3C3h bit 0.

3C4h index FDh (R/W):  Extended Timing Select

3C4h index FEh (R/W):  Foreground/Background Control
bit   0  Unused
      1  Foreground/background source select
         Source is CPU data if set, 3C4h index F5h else.
    2-3  Foreground/background mode select
           0  Set/Reset Output (Standard VGA) mode
           1  Solid Color Expansion Mode
              A monochrome bitmap is expanded to color.
              For each bit of data written from the processor
              a zero bit causes the background color (3C4h index FBh)
              to be written in the corresponding pixel, and a 1 bit
              causes the ForeGround color (3C4h index FAh) to be written.
           2  Dithered ForeGround. The data from the processor is
              replaced by data from four Foreground Latches (3C4h index
              ECh to EFh). The normal VGA Read Latches function as normal.
           3  Uses Background Latch (transparent).
    4-7  Unused

3C4h index FFh (R/W):  16 bit Interface Control
bit   0  16 bit memory if set
      1  16 bit I/O if set
      2  Fast Write Enabled if set
      3  16 bit ROM access if set
      4  Enable bank selection (Access to memory >256K) if set.
    5-6  Cursor Pattern Page Select
         Select which 256k bank the cursor pattern is in.
      7  (Read only) Card in 8 or 16 bit slot

3d4h index 1Fh (R):  Identification register
bit 0-7  Returns bit 0-7 of the Start Address High Register
         (3d4h index 0Ch) XORed with 0EAh.

3d4h index 22h (R):  Graphics Controller Data Latch
bit 0-7  Data from one of 4 bit-planes selected through the
         RMS field of the Read Map Select Register (3CEh index 4)

3d4h index 24h (R):  Graphics Controller Data
bit 0-4  Attribute Index. Same as 3C1 bit 0-4.
      5  Palette source.  Same as 3C1h bit 5
      7  Does the Attribute Controller point to Index or Data .

3d4h index 30h-3Fh (W):  Clear Vertical Display
bit   0  if set speeds up video memory access by increasing the
         vertical Retrace Period.


46E8h (W):  ROM Map & Video Subsystem
bit 0-2  Enable VGA PC/AT
      3  Enable VGA PC/AT if set
      4  Enter VGA Setup Mode if set
         In Setup Mode only registers 102h, 3C3h and 46E8h
         are active.


    4BC4h,4BC5 used.


  Bank Select:

    Two methods exists:

    All models can use method 1:
      For 2 and 4 color modes bit 16 of the address is in 3C2h bit 5.

      For 16 color modes separate read and write banks can be selected
      through 3C4h index F6h.

      For 256 color modes the bank fields in 3C4h index F6h select
      bit 18&19 of the video memory address.
      Bit 16 is selected through 3C4h index F9h bit 0.
      Bit 17 is selected through Miscellaneous Output Register
             (3C2h/3CCh bit 5).
      Bit 16&17 are shared by read and write operations.

    For Version 4 (HT208-A) and above separate bank registers are available.
    Both read and write banks exists.


  ID Video 7 VGA Chip Set:

    vio($6F00);
    if rp.bx=$5637 then
    begin
      vio($6F07);
      SubVers:=(rdinx($3C4,$8F) shl 8) + rdinx($3C4,$8E);
      case SubVers of
     $8000..$FFFF:VEGA_VGA;
     $7000..$70FF:HT208 version 1-3
     $7140..$714F:HT208 rev A;
            $7151:HT208 rev B
            $7152:HT208 rev CD
            $7760:HT216 rev BC
            $7763:HT216 rev D
            $7764:HT216 rev E
            $7765:HT216 rev F
      end;
    end;


  Video Modes:
    40h  T   80   43  16
    41h  T  132   25  16
    42h  T  132   43  16
    43h  T   80   60  16
    44h  T  100   60  16
    45h  T  132   28  16

    60h  G  752  410  16  PL4
    61h  G  720  540  16  PL4
    62h  G  800  600  16  PL4
    63h  G 1024  768   2  PL1
    64h  G 1024  768   4  PL2E
    65h  G 1024  768  16  PL4
    66h  G  640  400 256  P8    V1024 w/VRAM
    67h  G  640  480 256  P8
    68h  G  720  540 256  P8    VRAM only
    69h  G  800  600 256  P8    VRAM only
    6Ah  G 1024  768 256  P8
    70h  G 1280 1024  16  PL4


  BIOS extensions:

----------106F00-----------------------------
INT 10 - VIDEO - INSTALLATION CHECK (Video7 VGA,VEGA VGA)
        AX = 6F00h
Return: BX = 5637h ('V7') indicates Video7 VGA/VEGA VGA extensions are present
           = 4850h ('HP') indicates HP Extended BIOS video functions present
----------106F01-----------------------------
INT 10 - VIDEO - Get Monitor Info (Video7 VGA,VEGA VGA)
        AX = 6F01h
Return: AL = monitor type code (HP and VEGA VGA only) (values are for HP)
              00h  non-HP card with ROM and possibly its own INT 10h driver
              41h  MultiMode video display adapter
              45h  standard monochrome display adapter
              46h  standard color display adapter
        AH = status register information
             bit  0 = display enable
                      0 = display enabled
                      1 = vertical or horizontal retrace in progress
             bit  1 = light pen flip flop set
             bit  2 = light pen switch activated
             bit  3 = vertical retrace if set
             bit  4 = monitor resolution
                      0 = high resolution (>200 lines)
                      1 = low resolution (<=200 lines)
             bit  5 = display type
                      0 = color
                      1 = monochrome
             bits6,7= diagnostic bits
        CL = current value of Extended Control register
             (HP, and only if AL=41h)
Note: bits 0-3 are the same as the EGA/VGA status register bits 0-3
----------106F02-----------------------------
INT 10 - VIDEO - HP Vectra (Video7 ?) - Set Monitor Info
        AX = 6F02h
        BL = new value for extended control register
             Bit 0  Screen resolution (0: 200 lines, 1: 400)
                 1  Underline enable (if set 'blue' bit of ForeGround color is
                    the underline bit)
                 2  Font. 0: Standard-8, 1: HP-Roman-8
                 3  Memory disabled for CPU access
                 4  Allow access to full 32K memory rather than wrap at 16K
                 5  Select 2nd 16K page rather than first
Note: this function is only valid when an HP MultiMode Video Display Adapter
      is installed. The Extended Control register is at I/O address 3DDh
----------106F03-----------------------------
INT 10 - VIDEO - HP Vectra (Video7 ?) - Modify Monitor Info
        AX = 6F03h
        BH = Exclude mask (set bits are not modified)
        BL = new value for bits indicated in BH
             Result = ((old value) and BH) or ((not BH) and BL)
Note: This function is only valid when an HP MultiMode Video Display Adapter
      is installed
----------106F04-----------------------------
INT 10 - VIDEO - Get Mode and Screen Resolution (Video7 VGA, VEGA VGA)
        AX = 6F04h
Return: AL = current video mode (see AX=6F05h)
        BX = horizontal columns (text) or pixels (graphics)
        CX = vertical columns (text) or pixels (graphics)
----------106F05-----------------------------
INT 10 - VIDEO - Set Video Mode (Video7 VGA, VEGA EXTENDED EGA/VGA)
        AX = 6F05h
        BL = mode:
              00h-13h = standard IBM modes (see AH=00h)
              40h-6Ah = see table above.
----------106F06-----------------------------
INT 10 - VIDEO - SELECT AUTOSWITCH MODE (V7VGA,VEGA VGA)
        AX = 6F06h
        BL = Autoswitch mode select
             00h select EGA/VGA-only modes
             01h select Autoswitched VGA/EGA/CGA/MGA modes
             02h select 'bootup' CGA/MGA modes
        BH = enable/disable (00h enable, 01h = disable selection)
----------106F07-----------------------------
INT 10 - VIDEO - GET VIDEO MEMORY CONFIGURATION (V7VGA,VEGA VGA)
        AX = 6F07h
Return: AL = 6Fh
        AH = bits 0-6 = number of 256K blocks of video memory
             bit 7    = DRAM/VRAM (0: DRAM, 1: VRAM)
        BH = chip revision (SR8F) (S/C Chip in VEGA VGA)
        BL = chip revision (SR8E) (G/A Chip in VEGA VGA)
        CX = 0000h