82540EP — Networking Silicon
14
Datasheet
3.5
PHY Signals
3.5.1
Crystal Signals
3.5.2
Analog Signals
Symbol
Type
Name and Function
XTAL1
I
Crystal One.
The Crystal One pin is a 25 MHz +/- 50 ppm input signal. It can be
connected to either an oscillator or crystal. If a crystal is used, Crystal Two (XTAL2)
must also be connected.
XTAL2
O
Crystal Two.
Crystal Two is the output of an internal oscillator circuit used to drive a
crystal into oscillation. If an external oscillator is used in the design, XTAL2 must be
disconnected.
Symbol
Type
Name and Function
REF
P
Reference.
This Reference signal should be connected to VSS through an external
2.49 K
Ω
resistor.
MDI[0]+/-
A
Media Dependent Interface [0].
1000BASE-T
: In MDI configuration, MDI[0]+/- corresponds to BI_DA+/-, and in MDI-X
configuration, MDI[0]+/- corresponds to BI_DB+/-.
100BASE-TX
: In MDI configuration, MDI[0]+/- is used for the transmit pair, and in MDI-X
configuration, MDI[0]+/- is used for the receive pair.
10BASE-T
: In MDI configuration, MDI[0]+/- is used for the transmit pair, and in MDI-X
configuration, MDI[0]+/- is used for the receive pair.
MDI[1]+/-
A
Media Dependent Interface [1].
1000BASE-T
: In MDI configuration, MDI[1]+/- corresponds to BI_DB+/-, and in MDI-X
configuration, MDI[1]+/- corresponds to BI_DA+/-.
100BASE-TX
: In MDI configuration, MDI[1]+/- is used for the receive pair, and in MDI-X
configuration, MDI[1]+/- is used for the transit pair.
10BASE-T
: In MDI configuration, MDI[1]+/- is used for the receive pair, and in MDI-X
configuration, MDI[1]+/- is used for the transit pair.
MDI[2]+/-
A
Media Dependent Interface [2].
1000BASE-T
: In MDI configuration, MDI[2]+/- corresponds to BI_DC+/-, and in MDI-X
configuration, MDI[2]+/- corresponds to BI_DD+/-.
100BASE-TX
: Unused.
10BASE-T
: Unused.
MDI[3]+/-
A
Media Dependent Interface [3].
1000BASE-T
: In MDI configuration, MDI[3]+/- corresponds to BI_DD+/-, and in MDI-X
configuration, MDI[3]+/- corresponds to BI_DC+/-.
100BASE-TX
: Unused.
10BASE-T
: Unused.
