24.4 Signal Description

The GMAC includes the following signal interfaces:

• MII, RMII to an external PHY
• MDIO interface for external PHY management
• Client APB interface for accessing GMAC registers
• Host AHB interface for memory access

• Internal GTSUCOMP signal for TSU timer count value comparison

  Table 24-1. GMAC Connections in Different Modes

  Signal Name	Function	MII	RMII
  GTXCK	Transmit Clock or Reference Clock	TXCK	REFCK
  GTXEN	Transmit Enable	TXEN	TXEN
  GTX[3..0]	Transmit Data	TXD[3:0]	TXD[1:0]
  GTXER	Transmit Coding Error	TXER	Not Used
  GRXCK	Receive Clock	RXCK	Not Used
  GRXDV	Receive Data Valid	RXDV	CRSDV
  GRX[3..0]	Receive Data	RXD[3:0]	RXD[1:0]
  GRXER	Receive Error	RXER	RXER
  GCRS	Carrier Sense and Data Valid	CRS	Not Used
  GCOL	Collision Detect	COL	Not Used
  GMDC	Management Data Clock	MDC	MDC
  GMDIO	Management Data Input/Output	MDIO	MDIO