Adding a LAN module to Compute Module 3

Question

For an alarm with wired sensors and home automation purposes, I want to use a compute module 3 (for its eMMC reliability) but I have an issue ; I need a LAN connection.

In one of your answers Eliette suggest to use an enc28j60 module but I already own a WIZ850io and prefer this module.

1. Does the driver exist ?
2. Is it possible to add "dtoverlay=w5500" in the config.txt ?

Answer 1

Does the driver exist ?

Yes, there is a driver which was mainlined in version 5.3. Raspbian is currently using version 4.19, so you'll have to wait or build the driver yourself. Running rpi-update is also worth a try, judging by the github they are already testing version 5.5.

Is it possible to add "dtoverlay=w5500" in the config.txt ?

You'll have to write the overlay file first. It's still the same "Ethernet over SPI" inteface as ENC28J60, so I'd take the enc28j60 overlay as a starting point. Maybe it will even work as is.

Answer 2

As of bump to 4.19.80 the w5500 driver exists, at least for SPI0.

I did a short test with RPi Zero (Buster lite) and everything performed as expected.

Name: w5500

Info: Overlay for the Wiznet W5500 Ethernet Controller on SPI0

Load: dtoverlay=w5500,<param>=<val>

Params:

• int_pin: GPIO used for INT (default 25)
• speed: SPI bus speed (default 30000000)
• cs: SPI bus Chip Select (default 0)

https://github.com/raspberrypi/firmware/tree/master/boot/overlays

You will probably want to assign it some kind of a static MAC address though.