ESP32 Forum

Guidelines seemed to have changed between v5.2 and v6.0.2(stable); can I drive with a 3.3v external clock?:

https://docs.espressif.com/projects/esp ... _time.html
External 32 kHz oscillator: Allows using a 32 kHz clock generated by an external circuit.
The external clock signal must be connected to the external oscillator pin.
The input amplitude must ensure that the digital circuit can correctly distinguish between
logic high and low levels. Test results show that 1.7 V is the threshold between high and low levels.
Therefore, make sure the input waveform has a peak value greater than 1.7 V and a minimum value lower
than 1.7 V. For details on pin connections, please refer to the datasheet.


https://docs.espressif.com/projects/esp ... _time.html
External 32 kHz oscillator at XTAL_32K_P pin: Allows using 32 kHz clock generated by an
external circuit. The external clock signal must be connected to the XTAL_32K_P pin.
The amplitude should be less than 1.2 V for sine wave signal and less than 1 V for square wave signal.
Common mode voltage should be in the range of 0.1 < Vcm < 0.5xVamp, where Vamp stands for signal
amplitude. In this case, the XTAL_32K_P pin cannot be used as a GPIO pin.*/

That's weird (indeed). To me it looks like a typo. Seems to me they actually mean the amplitude needs to be at least 1.7V. I'd file a bug report. In my experience the bug reports are read by quite a lot more people from Espressif than the forum.