82540EP — Networking Silicon

3.2.6Power Management Signals

Symbol

Type

Name and Function

 

 

 

LAN_

 

Power Good (Power-on Reset). The Power Good signal is used to indicate that stable

PWR_

I

power is available for the 82540EP. When the signal is low, the 82540EP holds itself in

GOOD

 

reset state and floats all PCI signals.

 

 

 

 

 

Power Management Event. The 82540EP device drives this signal low when it

PME#

OD

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.

 

 

 

 

 

3.2.7Impedance Compensation Signals

Symbol

Type

Name and Function

 

 

 

 

 

N Device Impedance Compensation. This signal should be connected to an external

ZN_COMP

I/O

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.

 

 

 

 

 

P Device Impedance Compensation. This signal should be connected to an external

ZP_COMP

I/O

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.

 

 

 

3.2.8SMB Signals

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.

 

 

 

3.3EEPROM and Serial FLASH Interface Signals

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.

 

 

 

 

 

12

Datasheet

Page 18
Image 18
Intel 82540EP manual Eeprom and Serial Flash Interface Signals, Power Management Signals, Impedance Compensation Signals