
Tandberg Data
Hardware Interface
___________________________________________________________________________
Tandberg SLR Reference Manual
8-17
8.5.2. Reset Condition
The Reset Condition occurs when one of the devices on the SCSI-bus asserts RST. It is used
to immediately clear all devices from the bus, and reset their associated equipment.
Regardless of prior bus phase, the bus enters the Bus Free Phase. The Reset Condition must
last at least 25 µs.
8.5.3. Phase Sequencing
The bus phases follow a prescribed sequence. However, the Reset Condition can abort any
phase and force the bus to the Bus Free Phase. The Phase Sequence for systems with or
without Arbitration are shown in the figures below:
RESET condition
BUS FREE
phase
ARBITRATION
phase
SELECTION or
RESELECTION
phase
COMMAND or
DATA or
STATUS or
MESSAGE phase
Figure 8.10 Phase Sequencing for systems using Arbitration
RESET condition
BUS FREE
phase
SELECTION
phase
COMMAND or
DATA or
STATUS or
MESSAGE phase
Figure 8.11 Phase Sequencing for non-arbitrating systems