The Media Independent Interface is a synchronous 4-bit wide nibble data interface that connects the PHY to the MAC in 100BASE-FX, 100BASE-TX and 10BASE-Te modes. The MII is fully compliant with IEEE 802.3-2002 clause 22.
The MII signals are summarized below:
|Transmit and Receive Signals||TX_EN|
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 or transmission of data. The COL signal asserts as an indication of a collision which can occur during Half-Duplex mode when both transmit and receive operations occur simultaneously.