M3099GX/GH OEM Manual 3-9
INTERFACE
Signal Values
Signals may assure true or false values. These are two methods of
driving these signals. In both cases, the signal shall be actively driven
true, or asserted. In the case of OR tied drivers, the driver does not
drive the signal to the false state, rather the bias circuitry of the bus
terminators pulls the signal false whenever it is released by the drivers
at every SCSI device. If any driver is asserted, then the signal is true.
In the case of non OR tied drivers, the signal may be actively driven
false. In this standard, whenever the term negated is used, it means
that the signal may be actively driven false, or may be simply released
(in which case the bias circuitry pulls it false), at the option of the
implementor.
Signal Source
Table 3.4. indicates which type of SCSI device is allowed to source
each signal. No attempt is made to show if the source is driving
asserted driving negated, or is passive. All SCSI device drivers that are
not active sources be in the passive state. The RST signal may be
asserted by any SCSI device at any time.
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