Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface
Datasheet
SMSC LAN9420/LAN9420i
19
Revision 1.22 (09-25-08)
DATASHEET
Table 2.5 PLL and Ethernet PHY Pins
NUM
PINS
NAME
SYMBOL
BUFFER
TYPE
DESCRIPTION
1
Crystal Input
XI
ICLK
Crystal Input:
External 25MHz crystal input. This pin
can also be driven by a single-ended clock oscillator.
When this method is used, XO should be left
unconnected.
1
Crystal
Output
XO
OCLK
Crystal Output:
External 25MHz crystal output.
1
Ethernet TX
Data Out
Negative
TPO-
AIO
Ethernet Transmit Data Out Negative:
The transmit
data outputs may be swapped internally with receive
data inputs when Auto-MDIX is enabled.
1
Ethernet TX
Data Out
Positive
TPO+
AIO
Ethernet Transmit Data Out Positive:
The transmit
data outputs may be swapped internally with receive
data inputs when Auto-MDIX is enabled.
1
Ethernet RX
Data In
Negative
TPI-
AIO
Ethernet Receive Data In Negative:
The receive data
inputs may be swapped internally with transmit data
outputs when Auto-MDIX is enabled.
1
Ethernet RX
Data In
Positive
TPI+
AIO
Ethernet Receive Data In Positive:
The receive data
inputs may be swapped internally with transmit data
outputs when Auto-MDIX is enabled.
1
External
PHY Bias
Resistor
EXRES
AI
External PHY Bias Resistor:
Used for the internal
PHY bias circuits. Connect to an external 12.4K 1.0%
resistor to ground.