ESP32-U4WDH crystal mandatory ?

[Koxx33]

Hello,
I was using a ESP32-PICO-D4 and had no trouble (except hand soldering because of LGA package format ... which is a pain).
I moved to ESP32-U4WDH and I can't start the ESP32 (nothing on serial on boot, and impossible to flash).

Soldering is good.
I routed and VCC, GND, IO0, CHIP_PU.
CHIP_PU signal LOW to HIGH is delayed of more than 50us.
MDTI is forced to low to use embedded flash at 3.3V.
but nothing ...

I realized ESP32-U4WDH may not have internal crystal.
Internal oscillator can work without it ?
Is external crystal mandatory for this chip ?

[ZiyadEd]

For anyone who sees this later:

Yes the whole ESP32 series requires an external 40MHZ crystal clock source, I learnt it the hard way aswell

should have read this while designing the PCB: https://docs.espressif.com/projects/esp ... ock-source