Hi,
The following description is provided under the Eth_InternalLoopback example:
"This application demonstrates the progress transmit and receive in internal loopback mode, speed 100 Mbps so Tx, Rx clocks need to provide a frequency 25 MHz.
Tx clock will be received from PHY so to ensure this please reset board before use."
For which, only TX/RX clock should be configured to physically receive signals, all others will be internally connected. Since the MAC Layer subtype is REDUCED and the speed is 100M, RMII can fulfill this configuration. Under the RGMII standard [Page 8, v1.3, 12/10/2000], the following told:
"This interface can be used to implement the 10/100 Mbps Ethernet Media Independent Interface (MII) by reducing the clock rate to
25MHz for 100Mbps operation and 2.5MHz for 10Mbps. "
For which, RGMII is still able to be reconfigured for 100/10 functionality, with the respective changes.
Don't know if this information helps.
Please, let us know.