GMII

GMII=Gigabit Media Independent Interface(千兆介質無關接口)

GMII defines the logical and electrical characteristics for the Reconciliation Sublayer (RS) and Gigabit Media Independent Interface (GMII) between CSMA/CD media access controllers and various PHYs. Figure 1 shows the relationship of the Reconciliation sublayer and GMII to the ISO/IEC OSI reference model.

The purpose of this interface is to provide a simple, inexpensive, and easy-to-implement interconnection between Media Access Control (MAC) sublayer and PHYs, and between PHYs and Station Management (STA) entities。

1.It is capable of supporting 1000 Mb/s operation.

2.Data and delimiters are synchronous to clock references.

3.It provides independent eight-bit-wide transmit and receive data paths.

4.It provides a simple management interface.

5.It uses signal levels, compatible with common CMOS digital ASIC processes and some bipolar processes.

6.It provides for full duplex operation.

This clause applies to the interface between the MAC and PHYs, and between PHYs and Station Management entities. The GMII supports only 1000 Mb/s operation and is defined within this clause. Operation at 10 Mb/s and 100 Mb/s is supported by the MII. PHYs that provide a GMII shall support 1000 Mb/s operation, and may support additional rates using other interfaces (e.g., MII).