LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 117

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

Chapter 5
SCSI Operating
Registers
This section contains descriptions of all LSI53C875 operating registers.
Table 5.1
terms “set” and “assert” are used to refer to bits that are programmed to
a binary one. Similarly, the terms “deassert,” “clear,” and “reset” are used
to refer to bits that are programmed to a binary zero. Any bits marked as
reserved should always be written to zero; mask all information read from
them. Reserved bit functions may be changed at any time. Unless
otherwise indicated, all bits in registers are active HIGH, that is, the
feature is enabled by setting the bit. The bottom row of every register
diagram shows the default register values, which are enabled after the
chip is powered on or reset.
LSI53C875/875E PCI to Ultra SCSI I/O Processor
Note:
lists registers by operating and configuration addresses. The
The only register that the host CPU can access while the
LSI53C875 is executing SCRIPTS is the
(ISTAT)
interferes with the operation of the chip. However, all
operating registers are accessible with SCRIPTS. All read
data is synchronized and stable when presented to the PCI
bus. The LSI53C875 cannot fetch SCRIPTS instructions
from the operating register space. Instructions must be
fetched from system memory or the internal SCRIPTS
RAM.
register. Attempts to access other registers
Interrupt Status
5-1