Open SCSI Integrator's Manual for NonStop S-Series Servers

The SCSI SAC
Open SCSI Integrator’s Manual for NonStop Servers—422988-002
7-4
Supported Bus-Phase Transitions
Table 7-2. Bus-Phase Transitions Supported by the SCSI SAC
From
Phase
Transition TO Phase
Sel-
ect
Re-
sel-
ect
Msg
Out
Msg
In Cmd
Data
Out
Data
In Status Bus-Free
Bus-Free OK OK NA NA NA NA NA NA NA
Select NA NA OK OK Error Error Error OK Reset or
Timeout
Reselect NA NA OK OK Error Error Error OK OK
Msg Out NA NA SDTR ~ABT &
~BDR
~ABT &
~BDR &
~IDE &
~MPE
~ABT &
~BDR &
~IDE &
~MPE &
WR OP
~ABT &
~BDR &
~IDE &
~MPE &
RD OP
~ABT &
~BDR
Reset
Msg In NA NA OK ~CMP &
~DIS
~CMP &
~DIS
~CMP &
~DIS &
WR OP
~CMP &
~DIS &
RD OP
~CMP &
~DIS
Reset or
CMP or
DIS
Cmd NA NA OK OK Error WR OP RD OP OK Reset
Data Out NA NA OK OK Error OK Error OK Reset
Data In NA NA OK OK Error Error OK OK Reset
Status NA NA OK OK Error Error Error Error Reset
Term NA NA OK Error Error Error Error Error OK
~ABT Message sent is not Abort
~BDR Message sent is not Bus Device Reset
~CMP Message received is not Command Complete
CMP Command Complete message received
~DIS Message received is not Disconnect
DIS Disconnect message received
Error Invalid transition
~IDE Message sent is not Initiator Detected Error
~MPE Message sent is not Message Parity Error
NA Not applicable
OK Valid transition
RD OP Read operation
Reset SCSI RST signal asserted
SDTR Synchronous Data Transfer Request message (five bytes)
Timeout Timeout while waiting for BSY signal during the selection phase
WR OP Write operation
& “and”: links a group of conditions, all of which are necessary for the transition to
occur.