Wrover in IoE solution

[Dr.Knock]

Hello !
I would like yo use a Wrover version of ESP32 in our IoE solution. I need to use a hardware Ethernet in project and I try to use a LAN8720A chip.
But ! This pair doesn't work. Could you answer - is it correct to use Wrover version of ESP32 ?

[rpiloverbd]

Not sure about Wrover, but many had the same issue with WROOM.
https://github.com/espressif/arduino-esp32/issues/2907
viewtopic.php?t=5732

Here is a design using the Weemos version.
https://oshwlab.com/Antongsm/esp32-lan8720

Let's see if anyone has succeeded in performing the same task with WROVER.

[ESP_ondrej]

Could you please share more details about your hardware setup??

[Dr.Knock]

to rpiloverbd:
Yes, I was reading about that problems on WROOM, therefore I'd like to know more about WROVER version

to ESP_ondrej:
It's my version of connection. "No Asnwer" from LAN8720- it's result by asking after

[ESP_ondrej]

Dr.Knock, thanks for the schematics. The image is quite compressed but it seems you have RMII REF CLK incorrectly connected. It seems that REFCLKO and CLKIN are both wired to GPIO0 which is not correct. Since you want to use WROVER module, it requires external RMII CLK at GPIO0 (GPIO16/17 are already occupied by SPI memory so ESP32 internal EMAC CLK cannot be used). Therefore, you need to connect LAN8720 REFCLKO to ESP32 GPIO0 and CLKIN needs to be connected to external oscillator or crystal, see more details here.

There is one other thing which needs to be kept in mind! ESP32 GPIO0 is also used as boot strap pin so you need to be sure about its state during power-up or reset. If you connect LAN8720 REFCKLO to it, you might bet into a trouble during reset since there could be active CLK present and you would have 50:50 chance that the ESP won't boot correctly. It is caused by fact that the LAN8720 produces REFCLKO even if it is in reset state. Therefore, it would be ideal if you used external oscillator which would be programaticaly enabled once it is safe. Please refer to https://github.com/espressif/arduino-esp32/pull/6188 where the issue was discussed and solution proposed.