Card Power And Clock; 82558 Controller; Figure D-3. 82558 Controller; D.2.3 82558 Controller - Compaq EN Series Technical Reference Manual

D.2.2

CARD POWER AND CLOCK

The controller card includes on-board power logic that receives +5 VDC power from the PCI
connector or the WOL header. The PCI CLK signal provides the clock source for the controller
when the system is up and active. When the system is off or in Standby the on-board clock
generator provides the clock signal.
NOTE: Lack of a WOL header connection with the main system will result in the
controller board not receiving power at any time. Therefore the WOL header cable
should always be installed even if Wake-On-LAN functionality is not required.
D.2.3

82558 CONTROLLER

The Intel 82558 Fast Ethernet LAN controller provides most of the functionality of the card
(Figure D-3). The 82558 provides the following features:
Dual-mode support with auto-switching between 10BASE-T to 100BASE-TX PHY.
Digitally controlled adaptive equalization of transmission
Optimized PCI bandwidth with enhanced support of PCI commands.
ACPI support of power-down and wake-up states.
Wake On LAN (WOL) support.
LANDesk Service Agent (LSA) support.
Figure D-3 shows the internal architecture of the 82558 Ethernet controller.
AD31..0
PCI Bus
Figure D–3. 82558 Controller Internal Architecture
The 82558 controller features auto-negotiation of both speed and direction (half/full duplex). The
82558 provides high-level command support for minimum Host CPU intervention and uses 3-KB
FIFOs for both transmit and receive buffers.
82558 Ethernet Controller
Bus TX FIFO
I/F
Micro
FIFO Cntrl
Machine
4-Ch
DMA
Cntlr.
RX FIFO
Changed - June 1998
Technical Reference Guide
3-KB
10BASE-TX/
100BASE-T
PHY
3-KB
Compaq Personal Computers
TX Data
TX/RX
RX Data
Filters
D-3