5-22
SCSI SCRIPTS Instruction Set
The Set instruction is used to assert SATN/ on the SCSI
bus. The Clear instruction is used to deassert SATN/ on
the SCSI bus. The corresponding bit in the
register will be set or cleared
depending on the instruction used. Since SATN/ is an
initiator signal, it is not asserted on the SCSI bus unless
the LSI53C1000 is operating as an initiator.
The Set/Clear SCSI ACK/, ATN/ instructions are used
after message phase Block Move operations to give the
initiator the opportunity to assert attention before
acknowledging the last message byte. For example, if the
initiator wishes to reject a message, it issues an Assert
SCSI ATN instruction before a Clear SCSI ACK
instruction.
R
Reserved
[2:0]
5.3.2 Second Dword
This section describes the second Dword of the I/O Instruction register.
Figure 5.6
Second 32-Bit Word of the I/O Instruction
SA
Start Address
[31:0]
This 32-bit field contains the memory address to fetch the
next instruction if the selection or reselection fails.
If relative or table relative addressing is used, this value
is a 24-bit signed offset relative to the current
register value.
31
24 23
16 15
8
7
0
DSPS 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...