Avago Technologies LSI53C1010 - Manual (Page 252)

11-2 Using the SCRIPTS Processor in Target Applications
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Table 11.1 SCSI Protocol and Target SCRIPTS Instructions
Bus Phase Definition
SCRIPTS
Instruction
Bus Free Indicates that the SCSI bus is available. N/A
Arbitration Allows the initiator to gain control of the
SCSI bus. N/A
Selection During this phase, the target responds to
the initiator’s selection. WAIT SELECT
Message Out Target can receive messages from the
initiator, such as queuing and error
recovery information. MOVE WITH
MESSAGE OUT
Command Target can receive commands in the
form of a CDB to the target buffer. MOVE
Data In/Out Data In and Data Out phases send data
to the initiator or to the target and are
used dependent on the information
transferred during the Command phase.
This phase is optional. For example, a
Test Unit Ready command does not
require a data transfer. MOVE
Status Target sends status information to the
initiator about the previously executed
CDB. MOVE
Message In Target sends messages to the initiator.
These messages can acknowledge or
reject previously sent initiator messages.
They also can provide other information
like queuing, disconnect, or parity errors. MOVE
Disconnect Ends the target device's connection with
the bus. DISCONNECT
Bus Free After successful completion of an I/O
operation and a request for disconnect,
the bus returns to the Bus Free state,
indicating that it is now available. DISCONNECT