[Clock] ESP32 cannot be used as the PHY clock source if Wi-Fi and Ethernet are used at the same time

Affected revisions: v0.0 v1.0 v1.1 v3.0 v3.1

Description

In RMII working mode, the Ethernet MAC and PHY require a common 50 MHz reference clock (i.e., the RMII clock). If Wi-Fi and Ethernet are used simultaneously, the RMII clock cannot be generated by the internal APLL clock, as it would result in clock instability.

Workarounds

1. If you want to use the internal APLL to generate the reference clock, you need to disable Wi-Fi.

2. If you want to use both Ethernet and Wi-Fi simultaneously, you need to use an external PHY or external clock source to provide the reference clock.

Solution

No fix scheduled.