How to build ESP32 firmware to support LAN8720 Ethernet PHY

[yfyungit]

https://docs.micropython.org/en/latest/esp32/quickref.html#built-in-mac-original-esp32

I am trying to implement Ethernet communication using ESP32 + LAN8720, but I get the following error during testing. It seems that a custom firmware build is required.

OSError: esp_eth_driver_install failed

How do I configure and build ESP32 to support LAN8720 Ethernet PHY firmware?

[robert-hh]

LAN8720 ethernet support is built-in in the generic firmware. You have to make the proper connections and configuration. How dp you connect and configure the LAN8720 interface? Which board do you use?

[yfyungit]

I use the ESP32-DevKitC development board, the pin connections are as follows
https://docs.espressif.com/projects/esp-dev-kits/en/latest/esp32/esp32-devkitc/user_guide.html

lan = network.LAN(mdc=machine.Pin(23), mdio=machine.Pin(18), power=None,phy_type=network.PHY_LAN8720, phy_addr=0,ref_clk=machine.Pin(0), ref_clk_mode=machine.Pin.OUT)

[robert-hh]

In my tests with an Olimex board I used GPIO17 for ref_clk. But that one is only available for devices without PSRAM. Do you get the 50MHz ref_clk signal at GPIO0? You may as well try phy_addr=1. That depends on the wiring of your LAN8720 module.

[robert-hh]

Which LAN8720 module do you use? Some of them have the Clock circuit on-board, and then ref_clk may have to be input to the ESP32.

[robert-hh]

If the LAN8720 board has it's own crystal and outputs the ref_clk, then GPIO0 has to be used for ref_clk and ref_clk mode has to be machine.Pin.IN.

[yfyungit]

Thank you very much, I tested it successfully, LAN8720 successfully connected to Ethernet, using the following constructor

lan = network.LAN(mdc=Pin(23), mdio=Pin(18), power=None, phy_type=network.PHY_LAN8720, phy_addr=1, ref_clk=Pin(0), ref_clk_mode=Pin.IN)