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SGMII（Media Independent Interface）/ HiSGMII

Ethernet MAC和PHY之间通讯的一种接口，SGMII最高支持1000Mbps。

HiSGMII和SGMII接口相同，区别在于时钟，HiSGMII时钟频率为SGMII的2.5倍，速率只支持2.5Gbps。

常用标准

SGMII信号连接如下图：

SGMII各信号的定义见下表：

Table 13: SGMII Signal Definitions
Signal Name	Source	Description
SGIN±	Switch/MAC	Transmit data. Differential 1.25-Gbd transmit data from the Switch/MAC to the PHY.
SGOUt±	PHY	Receive data. Differential 1.25-Gbd receive data from the PHY to the Switch/MAC.
SCLK±	PHY	Transmit clock. Differential 625-MHz clock synchronized to the SGOUT± data. Some Switch/MACs can recover the clock from the SGOUT± data and do not need the SCLK±. If this is the case, then these pins can be left floating.