Avago Technologies LSI53C1030 - Manual (Page 36)

2-6 Functional Description
Version 2.2 Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
B_LED/. The LSI53C1030 firmware controls HB_LED/ (heartbeat LED),
which indicates that the IOP is operational.
A 2-wire serial interface provides a connection to a nonvolatile external
serial EEPROM. The serial EEPROM stores PCI configuration
parameters for the LSI53C1030. Refer to
Section 2.6, “Serial EEPROM
Interface,” for more information concerning the serial EEPROM.
2.1.2 SCSI Channel Module Description
The LSI53C1030 provides two independent Ultra320 SCSI bus channels.
Separate Ultra320 SCSI cores, datapath engines, and context managers
support each SCSI channel. Refer to
Section 2.4, “Ultra320 SCSI
Functional Description,” for an operational description of the LSI53C1030
SCSI bus channels.
2.1.2.1 Ultra320 SCSI Cores
The Ultra320 SCSI cores control their individual SCSI bus interface.
2.1.2.2 Datapath Engines
The datapath engines manage the SCSI side of DMA transactions
between their individual SCSI bus and the host system.
2.1.2.3 Context Managers
The context managers are ARM966E-S processors. Each context
manager controls the SCSI channel side of the LSI53C1030 Fusion-MPT
architecture for their individual SCSI bus. The context managers control
the outbound queues, target mode I/O mapping, disconnect and reselect
sequences, scatter/gather lists, and status reports.
2.2 Fusion-MPT Architecture Overview
The Fusion-MPT architecture provides two I/O methods for the host
system to communicate with the IOP: the system interface doorbell and
the message queues.
The system interface doorbell is a simple message passing mechanism
that allows the PCI host system and IOP to exchange single 32-bit Dword