LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 228

no-image

LSI53C875

Manufacturer Part Number
LSI53C875
Description
PCI to Ultra SCSI I/O Processor
Manufacturer
LSI Logic
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LSI53C875-160QFP
Manufacturer:
LSI
Quantity:
20 000
Part Number:
LSI53C875J
Manufacturer:
NS
Quantity:
4 490
Part Number:
LSI53C875J
Manufacturer:
LSILOGIC
Quantity:
20 000
6-32
CD
CP
WVP
DCM
Instruction Set of the I/O Processor
Bit 19
0
0
1
1
Compare Data
When this bit is set, the first byte received from the SCSI
data bus (contained in
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.
Compare Phase
When the LSI53C875 is in 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
LSI53C875 is operating in Target mode and this bit is set,
it tests for an active SCSI SATN/ signal.
Wait For Valid Phase
If the Wait for Valid Phase bit is set, the LSI53C875 waits
for a previously unserviced phase before comparing the
SCSI phase and data.
If the Wait for Valid Phase bit is cleared, the LSI53C875
compares the SCSI phase and data immediately.
Data Compare Mask
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
Byte Received (SFBR)
a mask of 01111111b and data compare value of
1XXXXXXXb allows the SCRIPTS processor to
determine whether or not the high order bit is set while
ignoring the remaining bits.
Result of
Compare
False
True
False
True
SCSI First Byte Received (SFBR)
data byte is ignored. For instance,
Action
Jump Taken
No Jump
No Jump
Jump Taken
SCSI First
[15:8]
18
17
16

Related parts for LSI53C875