ESP32 Forum

I was convinced that the ESP32-P4 only supports one ethernet port and we would have to use an external switch for redundancy

but there's a sentence in the datasheet that caught my eye:
"The Ethernet media access controller includes three RMII interfaces."
in page 70 of ESP32-P4 Series Datasheet v0.5 here: https://www.espressif.com/sites/default ... eet_en.pdf

so is it possible to have 3 ethernet ports if you connect 3 ethernet phy to these pins? or just one?

I can't find hard confirmation in the little while I've been looking, but I think this is because the PHY signals cannot be routed through the GPIO matrix and must be routed through the GPIO mux, meaning they can only come out of designated pins. What the text is trying to say is that most signals have three GPIOs they can be routed through, and you can mix and match between those for some flexibility wrt pin use.

The datasheet says "Communication with an external Fast Ethernet PHY through IEEE 802.3-compliant MII and RMII interfaces". The EMAC supports MII and RMII - two interface options are listed hence plural in "interfaces". Just to note that either MII or RMII can be used at a time.