Ethernet Guide

[blattm]

Hi! I'm trying to get a working Ethernet setup with either LAN8720 or W5500. There is an open issue about Ethernet, so I'm not sure if it is already support..?
Anyways, if I can get it running, I would like write up a beginner-friendly Ethernet guide (for the README or as a separate linked .md) including what I'll learn here :)

I have some questions:

• Do you have a recommendation for choosing Internal EMAC (with eg. LAN870) vs SPI Ethernet (with e.g. W5500) in terms of easiness of setup or quality? Do you have any other recommendations on choosing Ethernet hardware?
• Is connecting and setting PHY Reset GPIO number optional? Or does something special happen if it is set to -1?
• My esp32-audio-kit has some pin labled RST, but it doesn't have a GPIO number. Should I use this for PHY Reset with number -1?
• Is the SPI Host Number just an identifier, or do I need to set it to a specific value?
• My W5500 board does not have a CS0 pin, but a SCS pin. Is this just an alternative name?
• Is PHY Address a GPIO pin? the range 0-31 seems to imply that. But I have no idea where I would connect this to on a W5500 board...
• The esp32-audio-kit also has pins named tx0, rx0, but I guess these should not be used for lan8720's tx/rx channels, because it's for a different purpose?
• Pins labeled NC should not be connected, right?
• My LAN8720 chip has 9 relevant pins (besides ground, VCC, NCC), but in the config I can only set 3 GPIO numbers. Do the remaining pins stay unconnected? Or are there fixed pins to connect? Also, I'm not sure what pin on a LAN8720 board is for RST.
• Do you by any chance know why my W5500 could report it's version back as 0 instead of 4, causing a crash? (It's probably just me messing up the connection, but maybe you know something more about it...)

Thanks in advance :)

[blattm]

I read s.th. about soldering as a potential fix for Ethernet. If this is still relevant, I could try that, too :)

[CarlosDerSeher]

It really depends on the board design. I've built a custom board with LAN8720 which supplies RMII clock to esp32 via gpio0, but you must ensure the clock is not present during boot or it will fail to start most of the time. There is some information about internal mac. Most boards with LAN8720 out there have an active oscillator. Ensure that it is disabled during boot.

I don't have much to say about SPI ethernet, the code is mostly just taken from the espressif example.

NC == not connected / don't connect

My LAN8720 chip has 9 relevant pins

RMII pins are fixed. Check the documentation

PHY address for LAN8720 is configured through strap pins. This means there are pull up or pull down resistors on the board which set this during boot.

[anabolyc]

Just to make things simple, I have created a bunch of boards that have a W5500 ethernet header, so it is fairly easy to test and use. I was testing it with snapcast a long time ago, and I think it just worked.