Now I installed RPi OS Bookworm Light on both CM3+ and CM4S and tested them on my PCB without LAN9514 reset control.
With the CM3+ Ethernet always works correctly, at each power up and reboot. With the CM4S Ethernet also works correctly at power up but not after reboot. This makes me think that it might be a LAN9514 reset issue after all. However it is not clear why this has never been an issue with the CM3+. I can only think of some timing having changed with the CM4S.
So I soldered a GPIO to the LAN9514 reset pin but I am uncertain as to how to control it. I tried to configure the pin as output with pulldown in dt-blob.bin and then pull it high in config.txt. Unfortunately this doesn't resolve the Ethernet issue after reboot.
So has anyone an idea when exactly and how the reset signal should be given to the LAN9514? According to the data sheet it needs a low pulse of at least 1us.
With the CM3+ Ethernet always works correctly, at each power up and reboot. With the CM4S Ethernet also works correctly at power up but not after reboot. This makes me think that it might be a LAN9514 reset issue after all. However it is not clear why this has never been an issue with the CM3+. I can only think of some timing having changed with the CM4S.
So I soldered a GPIO to the LAN9514 reset pin but I am uncertain as to how to control it. I tried to configure the pin as output with pulldown in dt-blob.bin and then pull it high in config.txt. Unfortunately this doesn't resolve the Ethernet issue after reboot.
So has anyone an idea when exactly and how the reset signal should be given to the LAN9514? According to the data sheet it needs a low pulse of at least 1us.
Statistics: Posted by ondwis — Tue Dec 03, 2024 12:59 pm
