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Ultra SCSI controller
Ultra SCSI controller
The Adaptec 7880 chip is used for on-board support for Ultra SCSI. The user
can enable or disable this feature through the BIOS Setup screen. Connection
to the SCSI device is available on the front panel and the rear I/O transition
module via a 68-pin, high-density connector.
4
The Ultra SCSI circuitry provides for automatic termination when a device is
plugged into the rear or front. Devices can be connected to the rear, the front,
or both at the same time. Ground pins on the SCSI connector are reassigned to
act as cable or device detects. Two ground pins are used to distinguish between
16-bit or 8-bit devices. The active terminator used is a Dallas Semiconductor
DS2105Z. This part has a power down pin (PD-) that disconnects the
termination from the bus when driven low. This pin has an internal pull up
resistor.
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