I/O Instructions
5-17
Select Instruction
The LSI53C1000 arbitrates for the SCSI bus by asserting
the SCSI ID stored in the
register.
If it loses arbitration, it tries again during the next
available arbitration cycle without reporting any lost
arbitration status.
If the LSI53C1000 wins arbitration, it attempts to select
the SCSI device whose ID is defined in the destination ID
field of the instruction. Once the LSI53C1000 wins
arbitration, it fetches the next instruction from the address
pointed to by the
register.
This way the SCRIPTS can move to the next instruction
before the selection completes. It continues executing
SCRIPTS until a SCRIPT that requires a response from
the target is encountered.
If the LSI53C1000 is selected or reselected before
winning arbitration, it fetches the next instruction from the
address pointed to by the 32-bit jump address field stored
in the
register. Manually set
the LSI53C1000 to the initiator mode if it is reselected, or
to the target mode if it is selected.
If the Select with SATN/ field is set, the SATN/ signal is
asserted during the selection phase.
Wait Disconnect Instruction
The LSI53C1000 waits for the target to perform a “legal”
disconnect from the SCSI bus. A “legal” disconnect
occurs when SBSY/ and SSEL/ are inactive for a
minimum of one Bus Free delay (400 ns), after the
LSI53C1000 receives a Disconnect Message or a
Command Complete Message.
Wait Reselect Instruction
If the LSI53C1000 is selected before being reselected, it
fetches the next instruction from the address pointed to
by the 32-bit jump address field stored in the
register. Manually set the LSI53C1000
to the target mode when it is selected.
If the LSI53C1000 is reselected, it fetches the next
instruction from the address pointed to by the
register.
Содержание LSI53C1000
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 28: ...1 12 Introduction...
Страница 234: ...4 124 Registers...
Страница 314: ...6 40 Specifications This page intentionally left blank...
Страница 318: ...6 44 Specifications This page intentionally left blank...
Страница 344: ...6 70 Specifications This page intentionally left blank...
Страница 350: ...6 76 Specifications Figure 6 42 LSI53C1000 329 Ball Grid Array Bottom view...
Страница 352: ...6 78 Specifications...
Страница 360: ...A 8 Register Summary...
Страница 376: ...IX 12 Index...