Avago Technologies LSI53C896 - Manual (Page 260)

5-32 SCSI SCRIPTS Instruction Set
Version 3.3 Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.
CD Compare Data 18
When this bit is set, the first byte received from the SCSI
data bus (contained in the
SCSI First Byte Received (SFBR) 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 LSI53C896 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
LSI53C896 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 LSI53C896 waits
for a previously unserviced phase before comparing the
SCSI phase and data.
If the Wait for Valid Phase bit is cleared, the LSI53C896
compares the SCSI phase and data immediately.
MC Data Compare Mask [15:8]
The Data Compare Mask allows a SCRIPTS to test
certain bits within a data byte. During the data compare,
if any mask bits are set, the corresponding bit in the
SCSI First Byte Received (SFBR) 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