ESP32 Ethernet RMII pin reference

According to the ESP32 reference manual, section 4.10, Table 4-3, the following pins are relevant for Ethernet using the RMII interface:

ESP32 pinFunction
GPIO25EMAC_RXD0
GPIO26EMAC_RXD1
GPIO27EMAC_RX_DV
GPIO19EMAC_TXD0
GPIO22EMAC_TXD1
GPIO21EMAC_TX_EN
GPIO16EMAC_CLK_OUT
GPIO17EMAC_CLK_180

Note that typically theĀ EMAC_CLK_180 pin is used to let the ESP32 create a clock internally using its PLL and output it to the PHY.

For an example schematic using the ESP32 EMAC with RMII interface, see the Olimex ESP32-POE schematic or the ESP32 Ethernet Kit v1.2 schematic