imagine.txt

比较详尽的VGA端口寄存器的文档

#9 Imagine 128

304pin chip


REG+18h
bit  6-7  Video memory. 0: 4Mb, 1: 8Mb, 2: 16Mb, 3: 32Mb
      10

REG+1Ch
bit    2


  **** The PCI Interface registers ****
  Some of these may not be implemented. The ones marked with ; are in doubt

Byte 00h W(R):  Vendor ID
bit  0-15  105Dh for ??

Byte 02h W(R):  Device ID
bit  0-15  2309h for the Imagine 128

Byte 10h D(R/W):  Base0 (MW0 AD)
Bit     3  (R) Pre-fetchable. Set if memory is cacheable, clear if not.
    22-31  Memory Base. Upper 10bits of the base address.

Byte 14h D(R/W):  Base1 (MW1 AD)
Bit 22-31  Memory Base. Upper 10bits of the base address.

Byte 18h D(R/W):  Base2 (XYW AD(A))
Bit 22-31  Memory Base. Upper 10bits of the base address.

Byte 1Ch D(R/W):  Base3 (XYW AD(B))
Bit 22-31  Memory Base. Upper 10bits of the base address.

Byte 20h D(R/W):  Base4 (RBASE_G)
Bit 16-31  Memory Base. Upper 10bits of the base address.

Byte 30h D(R/W):  ROM Base
Bit     0  ROM BIOS Decode. Set to enable BIOS access
    15-31  BIOS Base Address. Upper 14-17 bits of the BIOS location. Depending
           on the BIOS size in bits 11-14 the lowest 1/2/3 bits may be forced
           to 0.