Compaq W4000 manual Tx/Rx Lan Phy I/F

Chapter 5 Input/Output Interfaces

5.9NETWORK INTERFACE CONTROLLER

These systems include a 10/100 Mbps network interface controller (NIC) consisting of a 82562- equivalent controller integrated into the 82801BA ICH2 component coupled with a physical interface (PHY) component and an RJ-45 jack with integral status LEDs (Figure 5-14). The support firmware is contained in the system (BIOS) ROM. The NIC can operate in half- or full- duplex modes, and provides auto-negotiation of both mode and speed. Half-duplex operation features an Intel-proprietary collision reduction mechanism while full-duplex operation follows the IEEE 802.3x flow control specification. Transmit and receive FIFOs of 3 kilobytes each reduce the chance of overrun while waiting for bus access.

82801 ICH2

Network

Interface

Function

TX/RX

LAN PHY I/F

Active/ RJ-45 Link Connector

(Green)

TX/RX

Speed (Yellow)

LED	Function
Green	Activity/Link: Indicates network activity and link pulse
	reception.
Yellow	Speed: Indicates link detection in 100 MB/s mode
	(always on if 100Base-Tx is forced).

Figure 5-13.Network Interface Controller Block Diagram

The Network Interface Controller includes the following features:

♦Fast Ethernet controller with 32-bit architecture and 3-KB TX/RX buffers.

♦Dual-mode support with auto-switching between 10BASE-T and 100BASE-TX.

♦Power down and Wake up support in both APM and ACPI environments (PME- and WOL).

♦Alert-on-LAN (AOL v1.0) support.

♦Link and Activity LED indicator drivers

♦AOL support for upgrade card

The controller features high and low priority queues and provides priority-packet processing for networks that can support that feature. The controller’s micro-machine processes transmit and receive frames independently and concurrently. Receive runt (under-sized) frames are not passed on as faulty data but discarded by the controller, which also directly handles such errors as collision detection or data under-run.

The NIC uses 3.3 VDC auxiliary power, which allows the controller to support Wake-On-LAN (WOL) and Alert-On-LAN (AOL) functions while the main system is powered down.

5-32Compaq Evo and Workstation Personal Computers

Featuring the Intel Pentium 4 Processor

Second Edition – January 2003