Avago Technologies LSI53C895A - Manual (Page 77)

SCSI Functional Description 2-51
The first option is to have the LSI53C895A load its PCI Subsystem ID
using a serial EPROM on power-up. If bit 15 in this ID is set, the
LSI Logic BIOS and operating system drivers (not all versions support
this capability) will ignore the chip. This makes it possible to control the
assignment of the mainboard SCSI controller using a configuration utility.
The second option is to provide mainboard and system BIOS support for
NVS. You can then enable or disable the LSI53C895A using the SCSI
BIOS configuration utility. Not all versions of the LSI Logic drivers support
this capability.
The third option is to have the system BIOS not report the existence of
the SCSI controller when the SCSI BIOS and operating systems make
PCI BIOS calls. This approach requires modifications to the system BIOS
and assumes the operating system uses PCI BIOS calls when searching
for PCI devices.
2.2.18 Chained Block Moves
Since the LSI53C895A has the capability to transfer 16-bit wide SCSI
data, a unique situation occurs when dealing with odd bytes. The
Chained Move (CHMOV) SCRIPTS instruction along with the Wide SCSI
Send (WSS) and Wide SCSI Receive (WSR) bits in the
SCSI Control
Two (SCNTL2) register are used to facilitate these situations. The
Chained Block Move instruction is illustrated in Figure 2.8 .