82598EB Datasheet, PDF (576/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Connecting the Light Emitting Diodes for Designs Based on
the 82598 Controller
8.11
Connecting the Light Emitting Diodes for Designs
Based on the 82598 Controller
The 82598 controller provides four programmable high-current push-pull (active high) outputs per port
to directly drive LEDs for link activity and speed indication. Each LAN device provides an independent
set of LED outputs; these pins and their function are bound to a specific LAN device. Each of the four
LED outputs can be individually configured to select the particular event, state, or activity, which will be
indicated on that output. In addition, each LED can be individually configured for output polarity, as well
as for blinking versus non-blinking (steady-state) indication.
The LED ports are fully programmable through the EEPROM interface, LEDCTL register. In addition, the
hardware-default configuration for all LED outputs can be specified via an EEPROM field, thus
supporting LED displays configurable to a particular OEM preference.
Please provide a separate current limiting resistors for each LED connected. Since the LEDs are likely to
be placed close to the board edge and to external interconnects, take care to route the LED traces away
from potential sources of EMI noise. In some cases, it may be desirable to attach filter capacitors.
8.12 Connecting the Miscellaneous Signals
8.12.1 LAN Disable
The 82598 has two signals that can be used for disabling Ethernet functions from system BIOS.
LAN0_DIS_N and LAN1_DIS_N are the separated port disable signals. Each signal can be driven from a
system output port. Choose outputs from devices that retain their values during reset. For example,
some ICH GPIO outputs transition high during reset. It is important not to use these signals to drive
LAN0_DIS_N or LAN1_DIS_N because these inputs are latched upon the rising edge of PE_RST_N or an
in-band reset end.
Each PHY may be disabled if its LAN function's LAN Disable input indicates that the relevant function
should be disabled. Since the PHY is shared between the LAN function and manageability, it may not be
desirable to power down the PHY in LAN Disable. The PHY_in_LAN_Disable EEPROM bit determines
whether the PHY (and MAC) are powered down when the LAN Disable pin is asserted. Default is not to
power down.
A LAN port can also be disabled through EEPROM settings. If the LAN_DIS EEPROM bit is set, the PHY
enters power down. Note, however, that setting the EEPROM LAN_PCI_DIS bit does not bring the PHY
into power down.
576