LAN8187_06 Datasheet, PDF (27/72 Pages) SMSC Corporation – ±15kV ESD Protected MII/RMII Fast-Ethernet PHY with HP Auto-MDIX and SMSC flexPWRTM

4.7
±15kV ESD Protected MII/RMII Fast-Ethernet PHY with HP Auto-MDIX and SMSC flexPWR^TM
Datasheet
Most of the MII and RMII pins are multiplexed. Table 4.2, "MII/RMII Signal Mapping", shown below,
describes the relationship of the related device pins to what pins are used in MII and RMII mode.
Table 4.2 MII/RMII Signal Mapping
SIGNAL NAME
TXD0
TXD1
TX_EN
RX_ER/
RXD4
COL/CRS_DV
RXD0
RXD1
TXD2
TXD3
TX_ER/
TXD4
CRS
RX_DV
RXD2
RXD3
TX_CLK
RX_CLK
CLKIN/XTAL1
MII MODE
TXD0
TXD1
TX_EN
RX_ER/
RXD4/
COL
RXD0
RXD1
TXD2
TXD3
TX_ER/
TXD4
CRS
RX_DV
RXD2
RXD3
TX_CLK
RX_CLK
CLKIN/XTAL1
RMII MODE
TXD0
TXD1
TX_EN
RX_ER
Note 4.2
CRS_DV
RXD0
RXD1
Note 4.1
Note 4.1
REF_CLK
Note 4.1 In RMII mode, this pin needs to tied to VSS.
Note 4.2 The RX_ER signal is optional on the RMII bus. This signal is required by the PHY, but it
is optional for the MAC. The MAC can choose to ignore or not use this signal.
Auto-negotiation
The purpose of the Auto-negotiation function is to automatically configure the PHY 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).
The auto-negotiation protocol is a purely physical layer activity and proceeds independently of the MAC
controller.
Revision 1.0 (12-14-06)
27
DATASHEET
SMSC LAN8187/LAN8187I