LSI 53C810A - Manual (Page 75)

LSI53C810A PCI to SCSI I/O Processor 5-1
Chapter 5
Operating Registers
This chapter describes all LSI53C810A operating registers. Table 5.1 , the
register map, lists registers by operating and configuration addresses.
The 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.
Note: The only register that the host CPU can access while the
LSI53C810A is executing SCRIPTS is the
Interrupt Status
(ISTAT) register. Attempts to access other registers
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 LSI53C810A cannot fetch SCRIPTS instructions from
the operating register space. Fetch instructions from
system memory.