Design Guide
System Overview
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Intel
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855GM/855GME Chipset Platform Design Guide 25
2. System Overview
2.1. Platform Component Features
The technologies represented by the Intel Centrino brand will include the Intel Pentium M processor,
related chipsets, and 802.11 (Wi-Fi) wireless networking capability. The Intel Pentium M processor is a
higher performance, lower power mobile processor with several micro-architectural enhancements over
existing Intel mobile processors. Key features include: Dynamic Execution; data pre-fetch logic; 400-
MHz, source-synchronous PSB; on-die, 1-MB second level cache with Advanced Transfer Cache
Architecture; Streaming SIMD Extensions 2 (SSE2); and Enhanced Intel
SpeedStep
technology.
Intel Centrino mobile technology also incudes the 855GM chipset components: the GMCH and the
ICH4-M. The accelerated hub architecture interface (the chipset component interconnect) is designed
into the chipset to provide an efficient, high bandwidth, communication channel between the GMCH
and the ICH4-M.
The GMCH component contains a PSB controller, a graphics controller, and a memory controller, while
providing an LVDS interface and two Digital Video Out ports. The ICH4-M component integrates USB
host controllers (supporting the USB 1.1 and USB 2.0 specification), an Ultra ATA 100/66/33
controller, a LAN controller, and an AC’97 digital controller, while providing interfaces for PCI and
LPC devices, as well as FWH Flash BIOS.
The integrated Wi-Fi Certified Intel PRO/Wireless 2100 Network Connection has been designed and
validated to work with all of the Intel Centrino™ mobile technology components and is able to connect
to 802.11b Wi-Fi certified access points. It also supports advanced wireless LAN security including
Cisco* LEAP, 802.1X, and WEP in addition to providing software-upgradeable support for future
security protocols, like WPA and full Cisco compatible features. Finally, for comprehensive security
support, the Intel PRO/Wireless 2100 Network Connection has been verified with leading VPN
suppliers like Cisco, CheckPoint*, Microsoft* and Intel NetStructure™.
An ACPI-compliant Intel 855GM / Intel 855GME chipset based system can support the Full-On (S0),
Power On Suspend (S1-M), Suspend to RAM (S3), Suspend to Disk (S4), and Soft-Off (S5) power
management states. Through the use of an appropriate LAN device, the chipset also supports wake-on
LAN* for remote administration and troubleshooting. The chipset architecture removes the requirement
for the ISA expansion bus that was traditionally integrated into the I/O subsystem of PCIsets/AGPsets.
This removes many of the conflicts experienced when installing hardware and drivers into legacy ISA
systems. The elimination of ISA provides true plug-and-play for the platform. Traditionally, the ISA
interface was used for audio and modem devices. The addition of AC’97 allows the OEM to use
software configurable AC’97 audio and modem coder/decoders (codecs) instead of the traditional ISA
devices.