SCRAM 2000 is a SCSI for A2000, A3000, A4000
- SCSI + RAM for A2000, 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 five custom logic chips:
- Bertie - controls the memory autoconfigure logic
- Cyril - SCSI autoboot controller chip
- Griswold - master timing controller for the DRAMs
- Ronald - controls RAM operation
- Dennis - main address decoder
- SCSI controller
- provides sockets for either an 8 or 16 bit SCSI controller IC:
- National Semiconductor DP8490V - an enhanced version of NCR 53C80
- NCR 53C94 - the card performs 50% faster with it
- the two controllers require different custom logic chips and autoboot ROM
- autoboot ROM - autobooting requires Kickstart 1.3
- autoboot disable switch for older Kickstarts or for game compatibility
- supports the Rigid Disk Block standard
- place for a 3.5" hard disk on the card
- hard disk power connector
- 50 pin internal SCSI header
- external DB25 SCSI connector
- SCSI access LED connector
- termination power option - jumper selectable +5V on pin 25 of the external connector and pin 26 of the internal header for using passive terminators
- 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
Autoconfig ID: 4096 / 3,4