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6 power management signals, 7 impedance compensation signals, 8 smb signals – Intel 82540EP User Manual

Page 18: 3 eeprom and serial flash interface signals, Power management signals, Impedance compensation signals, Smb signals, Eeprom and serial flash interface signals

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82540EP — Networking Silicon

12

Datasheet

3.2.6

Power Management Signals

3.2.7

Impedance Compensation Signals

3.2.8

SMB Signals

3.3

EEPROM and Serial FLASH Interface Signals

Symbol

Type

Name and Function

LAN_
PWR_
GOOD

I

Power Good (Power-on Reset).

The Power Good signal is used to indicate that stable

power is available for the 82540EP. When the signal is low, the 82540EP holds itself in
reset state and floats all PCI signals.

PME#

OD

Power Management Event.

The 82540EP device drives this signal low when it

receives a wake-up event and either the PME Enable bit in the Power Management
Control/Status Register or the Advanced Power Management Enable (APME) bit of the
Wake-up Control Register (WUC) is 1b.

AUX_PWR

I

Auxiliary Power.

If the Auxiliary Power signal is high, then auxiliary power is available

and the 82540EP device should support the D3cold power state.

Symbol

Type

Name and Function

ZN_COMP

I/O

N Device Impedance Compensation.

This signal should be connected to an external

precision resistor (to VDD) that is indicative of the PCI trace load. This cell is used to
dynamically determine the drive strength required on the N-channel transistors in the
PCI I/O cells.

ZP_COMP

I/O

P Device Impedance Compensation.

This signal should be connected to an external

precision resistor (to VSS) that is indicative of the PCI trace load. This cell is used to
dynamically determine the drive strength required on the P-channel transistors in the
PCI I/O cells.

Symbol

Type

Name and Function

SMBCLK

I/O

SMB Clock.

The SMB Clock signal is an open drain signal for serial SMB interface.

SMBDATA

I/O

SMB Data.

The SMB Data signal is an open drain signal for serial SMB interface.

SMBALRT#

O

SMB Alert.

The SMB Alert signal is open drain for serial SMB interface.

Symbol

Type

Name and Function

EE_DI

O

EEPROM Data Input.

The EEPROM Data Input pin is used for output to the memory

device.

EE_DO

I

EEPROM Data Output.

The EEPROM Data Output pin is used for input from the

memory device. The EE_DO includes an internal pull-up resistor.

EE_CS

O

EEPROM Chip Select.

The EEPROM Chip Select signal is used to enable the device.

EE_SK

O

EEPROM Serial Clock.

The EEPROM Shift Clock provides the clock rate for the

EEPROM interface, which is approximately 1 MHz.