RAID Controller Circuit Boards
50
•Cache DIMM memory
I/O Circuit Board The I/O circuit board provides the interface between the
enclosure and a host, as well as general support functions.
The I/O circuit board provides the following:
•Connections to the host
•Connections to the enclosure
•Dual switching power supply for +3.3 V and +2.5 V
•Hot pluggability for the controller
•Support for the BBU
The I/O circuit board has two SFF optical transceivers
supporting shortwave multimode fibre on the host side and a
90-pin controlled impedance (50 Ohm) connector on the
device side. An HSSDC connector with repeaters on the
expansion loop provides for a copper connection between
one of the device channels and an expansion module. Port
bypass circuitry on the I/O circuit board enables quadplex
operation on a second host loop. The I/O board has seven
LEDs to indicate subsystem status.
Ethernet Circuit
Board The ethernet circuit board provides a 10BASE-T/100BASE-
TX LAN connection for out of band service for the RAID
controller. Features of the ethernet circuit board include:
•PCI ethernet controller chip
•Enhanced scatter-gather bus mastering
•Operation in either full duplex or half-duplex mode
•Auto-negotiation for speed, duplex, and flow control
•RJ45 ethernet connector with integral activity and link status
LEDs
The PCI ethernet controller is a fully integrated 10BASE-T/
100BASE-TX controller consisting of both the media access
controller (MAC) and physical layer (PHY) in one package.