Amiga Hardware Database Expansion cards



SCRAM 500 Software
Company
Norman Jackson / MegaMicro, Australia
 Amiga
A500
 Interface
side expansion port
 Autoconfig ID
4096 / 3,4
  • SCSI + RAM for A500, a public domain kitware project
  • schematics, building instructions and driver software are all published
  • custom logic (GALs, PALs, etc.) are not published, these chips have to be ordered from the author
  • the four custom logic chips:
    • Bertie - controls the memory autoconfigure logic
    • Cyril - 8 bit SCSI autoboot controller chip
    • Griswold - master timing controller for the DRAMs
    • Humphrey - controls RAM operation
    SCSI controller
  • National Semiconductor DP8490V SCSI controller IC - an enhanced version of NCR 53C80
  • autoboot ROM - autobooting requires Kickstart 1.3
  • autoboot disable switch for older Kickstarts or for game compatibility
  • supports the Rigid Disk Block standard
  • external DB25 SCSI connector
  • SCSI access LED
  • termination power option - jumper selectable +5V on pin 25 for using passive terminator
  • non-DMA transfer
  • custom synchronising logic
    memory
  • 16 ZIP sockets accept up to 8 MB RAM
  • takes 256k×4 or 1M×4 ZIPs
  • ZIP sizes cannot be mixed
  • possible configurations are 0, 2, 4 or 8 MB
  • static column ZIPs work, but not improve performance
  • zero wait state
  • RAM access LED
  • autoconfigure LED
    notes
  • connects to the side expansion port
  • passthrough connector is optional
  • the case is wide enough for a companion board, the SCRAM-Jet - a 030 accelerator with 32 bit RAM, but it was never published
  • works with the A1000




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