Hi guys,
Thank you for brining this issue out and sorry for confusion.
I will get the guide corrected.

VanVince wrote:In other word which is the input voltage of VIN pin?

Hi Vincenzo,

According to DOIT Esp32 DevKit v1 documentation the recommended external input voltage range is from 7 to 12V.

Hi tmatsuzawa, This is an old guide and requires update to reflect audio applications recently developed by Espressif. The firmware and the method to load it to the LyraT board depends on the application you are interested in. * For Alexa like applications please check esp-avs-sdk * If you are inter...

And is there a guide somewhere telling precisely which GPIO, ADC ... you can use in which configuration (if possible, I would like to avoid this waste of time in the future) ? Hi Antoine, This is documented in Analog to Digital Converter section of the ESP32 Programming Guide. If you are interested...

Hi samsam and TheSub6,

Could you double check if this is not the issue described in Note on C15?

If you have C15 installed on your board then try removing it to see if this resolves the issue.

C15 has been removed ("NC" on the schematic) in the latest ESP32-DevKitC V4.

Hi Vignesh,

Please check ESP32 Modules and Boards > ESP32 DevKitC V4

Can I just remove those caps (C84 / C90) and connect to the cap pads with my adc inputs? John A Hi John, These caps were to enable Low Noise Amplifier (LNA) functionality. The LNA is not supported anyway, so you can safely remove the caps. The cap pads are available as regulars ADC inputs. The same...

Hi David, Indeed the minimum wakeup time is lower. My previous measurements were incorrect and included the program execution time. Sorry for that! I did separate check with the hardware design team and obtained more specific information. The minimum wakeup time represents clock cycles spend by ULP'...

Hi @dmarcos,

Good find! I see identical result. My assumption is that 160us you identified, is the time required by ULP to wake up by the timer and start running the code. I will investigate more and post here if have some new updates.

Explanation is provided in https://esp32.com/viewtopic.php?f=12&t= ... 278#p29278