Use half the number of data pins as used in the GMII.
This reduction is achieved by clocking data on both the rising and falling edges of the clock in 1000Mbit/s operation, and by eliminating non-essential signals.
Signals of RGMII
Signal name
Description
Direction
TXC
Clock signal
MAC to PHY
TXD[3..0]
Data to be transmitted
MAC to PHY
TX_CTL
Multiplexing of transmitter enable and transmitter error
MAC to PHY
RXC
Received clock signal (recovered from incoming received data)
PHY to MAC
RXD[3..0]
Received data
PHY to MAC
RX_CTL
Multiplexing of data received is valid and receiver error