LSI LSI53C896, Technical Manual

Page: 229 / 370

LSI53C896 PCI to Dual Channel Ultra2 SCSI Multifunction Controller 5-1
Chapter 5
SCSI SCRIPTS
Instruction Set
After power-up and initialization, the LSI53C896 can operate in the low
level register interface mode, or use SCSI SCRIPTS.
With the low level register interface, the user has access to the DMA
control logic and the SCSI bus control logic. An external processor has
access to the SCSI bus signals and the low level DMA signals, which
allow creation of complicated board level test algorithms. The low level
interface is useful for backward compatibility with SCSI devices that
require certain unique timings or bus sequences to operate properly.
Another feature allowed at the low level is loopback testing. In loopback
mode, the SCSI core can be directed to talk to the DMA core to test
internal data paths all the way out to the chip’s pins.
The following sections describe the benefits and use of SCSI SCRIPTS.
•
Section 5.1, “SCSI SCRIPTS”
•
Section 5.2, “Block Move Instructions”
•
Section 5.3, “I/O Instructions”
•
Section 5.4, “Read/Write Instructions”
•
Section 5.5, “Transfer Control Instructions”
•
Section 5.6, “Memory Move Instructions”
•
Section 5.7, “Load/Store Instructions”
5.1 SCSI SCRIPTS
To operate in the SCSI SCRIPTS mode, the LSI53C896 requires only a
SCRIPTS start address. The start address must be at a Dword (four
byte) boundary. This aligns all the following SCRIPTS at a Dword
boundary since all SCRIPTS are 8 or 12 bytes long. Instructions are
*