C.1.11.1 Host Adapter
The host adapter is a Symbios Logic PCI-SCSI I/O processor IC. The host adapter
and all target devices comply with the Fast-20 single-ended drivers and receivers
characteristics. The electrical characteristics of the output buffers include:
Vol(output low) equals 0 to 0.5 VDC with Iol at 48 mA (signal asserted)
Voh(out high) equals 2.5 to 3.7 VDC (signal negated)
trise (rising slew rate) equals520 mV per nanosecond maximum (0.7 to 2.3 VDC)
tfall (falling slew rate) equals 520 mV per nanosecond maximum(2.3 to 0.7 VDC)
The Fast-20 electrical characteristics for the host adapter and target device include:
Vil(input low) equals 1.0 VDC maximum (signal true)
Vih(input high) equals 1.9 VDC minimum (signal false)
Iil (input low current) equals +/- 20 mA at Vi equals 0.5 VDC
Iih (input high current) equals +/- 20 mA at Vi equals 2.7 VDC
Minimum input hysteresis equals 0.3 VDC
C.1.11.2 Supported Target Devices
The SCSI subsystem supports a maximum of four internal devices, including the host
adapter. The CD-ROM drive is a narrow device. A unipack with one drive or a
six-pack, accommodating six drives, can be used as external devices.
Functional Description 269