SCSI Registers
4-63
ERL
Enable Read Line
3
This bit enables a PCI Read Line command. If this bit is
set and the chip is about to execute a read cycle (other
than an opcode fetch), the command is 0b1110.
ERMP
Enable Read Multiple
2
If this bit is set and cache mode is enabled, a Read
Multiple command is used on all read cycles when it is
legal.
BOF
Burst Opcode Fetch Enable
1
Setting this bit causes the LSI53C1000 to fetch
instructions in burst mode. Specifically, the chip bursts in
the first two Dwords of all instructions using a single bus
ownership. If the instruction is a Memory-to-Memory
Moves type, the third Dword is accessed in a subsequent
bus ownership. If the instruction is an indirect type, the
additional Dword is accessed in a subsequent bus
ownership. If the instruction is a table indirect block move
type, the chip accesses the remaining two Dwords in a
subsequent bus ownership, thereby fetching the four
Dwords required in two bursts of two Dwords each. If
prefetch is enabled, this bit has no affect. This bit also
has no affect on fetches out of SCRIPTS RAM.
MAN
Manual Start Mode
0
Setting this bit prevents the LSI53C1000 from
automatically fetching and executing SCSI SCRIPTS
when the
register is
written. When this bit is set, the Start DMA bit in the
register must be set to begin SCRIPTS
execution. Clearing this bit causes the LSI53C1000 to
automatically begin fetching and executing SCSI
SCRIPTS when the
register is written. This bit normally is not used for SCSI
SCRIPTS operations.
Содержание LSI53C1000
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 28: ...1 12 Introduction...
Страница 234: ...4 124 Registers...
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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...