TLK110 Datasheet, PDF (20/104 Pages) Texas Instruments – Industrial Temp, Single Port 10/100Mbs Ethernet Physical Layer

TLK110
SLLS901A – DECEMBER 2011 – REVISED FEBRUARY 2012
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4.1 Media Independent Interface (MII)
The Media Independent Interface (MII) is a synchronous 4-bit wide nibble data interface that connects the
PHY to the MAC in 100B-TX and 10B-T modes. The MII is fully compliant with IEEE802.3-2002 clause 22.
The MII signals are summarized below.
Data signals
MII_TXD [3:0]
Transmit and receive-valid signals
RXD [3:0]
MII_TX_EN
Line-status signals
MII_RX_DV
CRS (carrier sense)
COL (collision)
Figure 4-1 shows the MII-mode signals.
PHY
TX_CLK
TX_EN
TXD [3:0]
RX_CLK
RX_DV
RX_ERR
RXD [3:0]
CRS
COL
TX_CLK
TX_EN
TXD [3:0]
RX_CLK
RX_DV
RX_ER
RXD [3:0]
CRS
COL
MAC
Figure 4-1. MII Signaling
The isolate register 0.10 defined in IEEE802.3-2002 used to electrically isolate the PHY from the MII (if
set, all transactions on the MII interface are ignored by the PHY).
Additionally, the MII interface includes the carrier sense signal CRS, as well as a collision detect signal
COL. The CRS signal asserts to indicate the reception of data from the network or as a function of
transmit data in Half Duplex mode. The COL signal asserts as an indication of a collision which can occur
during half-duplex operation when both transmit and receive operation occur simultaneously.
4.2 Reduced Media Independent Interface (RMII)
TLK110 incorporates the Reduced Media Independent Interface (RMII) as specified in the RMII
specification (rev1.2) from the RMII consortium. The purpose of this interface is to provide a low cost
alternative to the IEEE 802.3u [2] MII as specified in Clause 22. Architecturally, the RMII specification
provides an additional reconciliation layer on either side of the MII, but can be implemented in the absence
of an MII.
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