Avago Technologies LSI53C876E - Manual (Page 191)

LSI53C876/876E PCI to Dual Channel SCSI Multifunction Controller 5-1
Chapter 5
SCSI SCRIPTS
Instruction Set
After power up and initialization, the LSI53C876 can be operated in the
low level register interface mode or in the high level SCSI SCRIPTS
mode.
Chapter 5 is divided into the following sections:
•
Section 5.1, “Low Level Register Interface Mode”
•
Section 5.2, “High Level SCSI SCRIPTS Mode”
•
Section 5.3, “Block Move Instruction”
•
Section 5.4, “I/O Instruction”
•
Section 5.5, “Read/Write Instructions”
•
Section 5.6, “Transfer Control Instructions”
•
Section 5.7, “Memory Move Instructions”
•
Section 5.8, “Load and Store Instructions”
5.1 Low Level Register Interface Mode
With the low level register interface mode, 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
allows 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.