Intel 82600 manual Main Memory, LAN Subsystem

User Guide XB1 COM Express Module

Main Memory

The XB1 COM Express Module is equipped with two sockets for installing 200-pin SO-DIMM modules (module height = 1.25 inch). Supported are unbuffered DDR2 SO-DIMMs (VCC=1.8V) without ECC featuring on-die termination (ODT), according the PC2-3200 or PC2-4200 specification. Minimum memory size is 128MB; maximum memory size is 2GB. Due to the video requirements of the i915GM chipset (some of the system memory is dedicated to the graphics controller), a minimum of 2x256MB memory is recommended for the operating systems Windows NT 4.0, Windows 2000 or Windows XP.

The contents of the SPD EEPROM on the SO-DIMMs are read during POST (Power-on Self Test) to program the memory controller within the chipset.

The i915GM chipset supports symmetric and asymmetric memory organization. The maximum memory performance can be obtained by using the symmetric mode. To achieve this mode, two SO-DIMMs of equal capacity must be installed in the memory sockets. In asymmetric mode different memory modules may be used with the drawback of less bandwidth. A special case of asymmetric mode is to populate only one memory module (i.e. one socket may be left empty).

LAN Subsystem

The Ethernet LAN subsystem is comprised of the Intel 82573 Gigabit Ethernet controller, which provides also legacy 10Base-T and 100Base-TX connectivity.

<Single PCI Express lane linkage

<1000Base-Tx (Gigabit Ethernet), 100Base-TX (Fast Ethernet) and 10Base-T (Classic Ethernet) capability

<Half- or full-duplex operation

<IEEE 802.3u Auto-Negotiation for the fastest available connection

<Jumperless configuration (completely software-configurable)

The NIC (Networking Interface Controller) is connected by a single PCI Express lane to the chipset southbridge (ICH6). Its MAC address (unique hardware number) is stored in a dedicated EEPROM. The Intel Ethernet software and drivers for the 82573 is available from Intel's World Wide Web site for download (link provided on the EKF website).

By specification, the XB1 COM Express Module does not provide any I/O connector. Instead, the carrier board must provide the RJ45 receptacle with integrated magnetics for copper twisted pair Ethernet. All MDI (Media Dependent Interface) signals of the Ethernet PHY are routed to the connector J-COM A-B.

The 82573 controller is connected to the PCI Express lane #3. As an alternate stuffing option, this lane is available across the J-COM connector instead, for carrier board applications which require 4 PCIe lanes (typically configured as PCIe x 4 link). If this stuffing option had been ordered, no Ethernet connectivity is provided on the XB1 itself, but may be replicated on the carrier board.

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