ESP32 - Gateway rev E - idea and development nightmare story :)

[SejnyM]

Hello Olimex,

i used ESP32 and LAN8710A in my project. Same schematic as ESP32 GATEWAY in revision E.

But i have one week nightmare with unstable PHY initialization. This is gone...ufff

I recommend remove PHY power switch and ESP32 gpio connect directly to nRST pin of PHY.

In Espressif SDK is bug in ethernet initialization. Phy is powered and go out from reset before RMII clock output. In IDF 3.0 clock run 30ms after power pin go high, in new IDF v3,3(used in arduino) is this delay shorter(approx. 1,2ms).

This is completely wrong, LAN8710/LAN8720 datasheet says:

RMII CLOCK MUST BE PRESENT BEFORE RESET GO HIGH  ----> This is VERY important!

After remove PHY power switch(PHY is powered continously) and use nRST(PHY) and repair SDK.

After correcting these two errors, the device works flawlessly and always starts the first time.
 
I share this fact here so that no one else is unnecessarily worried about it. My colleague programmer creates an issue on the Esspresif GIT.

Sorry for my horrible english