Developed and applied to Fast Ethernet by 802.3u, MII connects the MAC layer and PHY layer in the Data Link Layer. The MII clock frequencies are 25MHz and 2.5MHz (for Ethernet), corresponding to signals TX_CLK and RX_CLK. There are 4-bit buses for both output and input: TX[0:3] and RX[0:3]. The start signals for output and input are TX_EN and RX_EN, and the error notification signals are TX_ER and RX_ER. The notification signal for valid input data is RX_DV, and the Collision signal for congestion on the network is COL. The circuit voltage for MII implementation can be either 5V or 3.3V.
SMI (Serial Management Interface) is the timing management interface for MII, also known as MDIO (Management Data Input/Output).
MII (Media Independent Interface):
MII is a standard interface used to connect Ethernet controllers (MAC) and Ethernet physical layers (PHY) for communication. It defines the data and control lines, operates at a speed of 10/100Mbps, SDR, with a maximum frequency of 25MHz.
RMII (Reduced Media Independent Interface):
RMII is a simplified version of MII, reducing the number of connection lines, saving space and cost. It is widely used in embedded systems and specific applications, operating at a speed of 10/100Mbps, SDR, with a maximum frequency of 50MHz.
GMII (Gigabit Media Independent Interface):
GMII supports higher-speed Ethernet, providing a data transfer rate of 1 Gbps. It has more signal lines to support high-speed communication, operating at speeds of 10/100/1000Mbps, SDR, with a maximum frequency of 125MHz.
RGMII (Reduced Gigabit Media Independent Interface):
RGMII is a simplified version of GMII, reducing the number of lines, suitable for applications with limited space and cost. It operates at speeds of 10/100/1000Mbps, DDR, with a maximum frequency of 125MHz.
These interface standards are commonly used in embedded systems, network devices, and other applications requiring Ethernet connectivity. The choice of interface depends on the application"s requirements and hardware design considerations.
