ESP32S3 with LAN8740 support.

[ZanzyTHEbar]

Hey ya'll. I am spinning up a board and i am in the testing R&D phase right now. My other STM32 boards all use the LAN8740 PHY, so i figured that i would use that in this project (familiarity). I am using the esp32s3 for this board.

i have a few questions to clarify some observations that i have made.

I took a look at framework-arduinoespressif32/libraries/Ethernet/src/ETH.cpp I noticed that with IDF v > 4.4 all of the LAN8720 driver stuff is marked as not selected in favour of the KSZ8081 is there a reason for this? Can i safely simply remove the bits i don't need and select for the LAN8740?

I also noticed that the sdkconfig.h automatically sets:

#define CONFIG_ETH_USE_SPI_ETHERNET 1
#define CONFIG_ETH_SPI_ETHERNET_DM9051 1
#define CONFIG_ETH_SPI_ETHERNET_W5500 1

I can not make changes to this, when i try, they do not compile in. Leading me to believe that this header is just for show and the real sdkconfig is pre-compiled ahead of time? If so, is there a way for me to change this? I'd like to use RMII, unless there is a reason that i shouldn't. I am not seeing anything in the datasheet for the esp32s3 that says's i shouldn't or couldn't use RMII.

I also noticed the .skip.esp32s3 what's the deal with this? Is this for testing and docs, or is this a skip file for compilation? I have a feeling its for internal development (CI/CD) and not compilation related - but i am curious.

Anywho - TLDR: I am looking to setup an esp32s3 with ethernet using the Arduino framework and i'd like to get some feedback on the most idiomatic way forward. Thanks :)

[me-no-dev]

Only ESP32 has RMII interface (and the upcoming ESP32-P4), but all other chips can do only SPI Ethernet

[ZanzyTHEbar]

The S3 doesn't have an RMII interface? Why? How did i miss that ... (rhetorical question, surprised i missed that in the datasheet). I am pretty excited for the upcoming P4.

[ZanzyTHEbar]

Ill switch to the esp32 wroom-32E then. That seems to have an RMII interface. Thanks for the heads up. Anything else i should pay attention to? For example - do i need to setup a custom board, or is there a compatible board json for ethernet enabled esp32 boards?

[ZanzyTHEbar]

/.platformio/packages/framework-arduinoespressif32/libraries/Ethernet/src/ETH.h:27:10: fatal error: WiFi.h: No such file or directory Tried to setup the example located under /.platformio/packages/framework-arduinoespressif32/libraries/Ethernet/examples/ETH_LAN8720 and it can't seem to find the WiFi.h which doesn't make sense at all. Only the ETH.h header fails to find the file, i can use wifi perfectly fine as long as i don't include the ETH.h header.