Amiga Hardware Database Expansion cards



GDA-1
Company
GfxBase, USA
 Date
1991
 Amiga
A2000, A3000, A4000
 Interface
Zorro II
 Autoconfig ID
2142 / 1,0
    graphics card
  • GDA = Graphics Display Adapter
  • 512 kB or 1 MB VRAM
  • the 512 kB GDA-1 is upgradable to 1 MB with four 256k×4 VRAMs
  • there is no graphics chip or graphics coprocessor on the card
    screen modes
  • 256 colours from the 16.7 million palette
  • 640×480, double buffering with 1 MB VRAM
  • 800×600, 16 colours with 512 kB, 256 colours with 1 MB VRAM
  • 1024×768, 16 colours with 512 kB, 256 colours with 1 MB VRAM
  • refresh rate is entirely dependent on the speed of the processor driving the card
  • since the display is driven by VRAMs (dual ported DRAMs) the processor will not be slowed down by display refresh like the standard Amiga graphics hardware
    notes
  • HD15 VGA connector
  • maps its memory directly into the Zorro II address space - limits the amount of fast RAM to 7 or 7.5 MB
  • the card can be used as regular RAM expansion when not used for display
  • a basic memory mapped frame buffer that is accessible to the programmer as one contiguous memory space
  • supported by the X Window System
  • does not support standard AmigaDOS screens



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