5-32
SCSI SCRIPTS Instruction Set
CD
Compare Data
18
When this bit is set, the first byte received from the SCSI
data bus (contained in the
register) is compared with the Data to be
Compared Field in the Transfer Control instruction. The
Wait for Valid Phase bit controls when this compare
occurs. The Jump if True/False bit determines the
condition (true or false) to branch on.
CP
Compare Phase
17
When the LSI53C1000 is in the initiator mode, this bit
controls phase compare operations. When this bit is set,
the SCSI phase signals (latched by SREQ/) are
compared to the Phase Field in the Transfer Control
instruction. If they match, the comparison is true. The
Wait for Valid Phase bit controls when the compare
occurs. When the LSI53C1000 is operating in the target
mode and this bit is set it, tests for an active SCSI SATN/
signal.
VP
Wait For Valid Phase
16
If the Wait for Valid Phase bit is set, the LSI53C1000
waits for a previously unserviced phase before comparing
the SCSI phase and data.
If the Wait for Valid Phase bit is cleared, the LSI53C1000
compares the SCSI phase and data immediately.
MC
Data Compare Mask
[15:8]
The Data Compare Mask allows a SCRIPT to test certain
bits within a data byte. During the data compare, if any
mask bits are set, the corresponding bit in the
data byte is ignored. For instance,
a mask of 0b01111111 and data compare value of
0b1XXXXXXX allows the SCRIPTS processor to
determine whether or not the high order bit is set while
ignoring the remaining bits.
Bit 19
Result of
Compare
Action
0
False
Jump Taken
0
True
No Jump
1
False
No Jump
1
True
Jump Taken
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...