lan8710 Standard Microsystems Corp., lan8710 Datasheet - Page 28

• Manufacturer Part Number: lan8710
• Description: Mii/rmii 10/100 Ethernet Transceiver With Hp Auto-mdix And Flexpwr Technology In A Small Footprint
• Manufacturer: Standard Microsystems Corp.

Revision 1.0 (04-15-09)
4.7
COL/CRS_DV/MODE2
Note 4.1
Note 4.2
The RMII REF_CLK is a continuous clock that provides the timing reference for CRS_DV, RXD[1:0],
TXEN, TXD[1:0] and RXER. The LAN8710 uses REF_CLK as the network clock such that no buffering
is required on the transmit data path. However, on the receive data path, the receiver recovers the
clock from the incoming data stream, and the LAN8710 uses elasticity buffering to accommodate for
differences between the recovered clock and the local REF_CLK.
The purpose of the Auto-negotiation function is to automatically configure the transceiver to the
optimum link parameters based on the capabilities of its link partner. Auto-negotiation is a mechanism
for exchanging configuration information between two link-partners and automatically selecting the
highest performance mode of operation supported by both sides. Auto-negotiation is fully defined in
clause 28 of the IEEE 802.3 specification.
Once auto-negotiation has completed, information about the resolved link can be passed back to the
controller via the Serial Management Interface (SMI). The results of the negotiation process are
reflected in the Speed Indication bits in register 31, as well as the Link Partner Ability Register
(Register 5).
LAN8710 PIN NAME
Auto-negotiation
nINT/TXER/TXD4
RXCLK/PHYAD1
RXD2/RMIISEL
RXD4/PHYAD0
RXD3/PHYAD2
RXD0/MODE0
RXD1/MODE1
XTAL1/CLKIN
TXCLK
RXER/
RXDV
TXD0
TXD1
TXEN
TXD2
TXD3
CRS
In RMII mode, this pin needs to tied to VSS.
The RXER signal is optional on the RMII bus. This signal is required by the transceiver,
but it is optional for the MAC. The MAC can choose to ignore or not use this signal.
Table 4.2 MII/RMII Signal Mapping
MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR
DATASHEET
28
XTAL1/CLKIN
MII MODE
RXCLK
TXCLK
TXER/
RXER
RXDV
TXEN
RXD0
RXD1
RXD2
RXD3
TXD0
TXD1
TXD2
TXD3
TXD4
COL
CRS
RMII MODE
SMSC LAN8710/LAN8710i
REF_CLK
®
CRS_DV
Note 4.2
Note 4.1
Note 4.1
Technology in a Small Footprint
TXEN
RXER
RXD0
RXD1
TXD0
TXD1
Datasheet