ESP32 Forum

I'm using the ESP32-S2FH4 which apparently has embedded flash memory. I'm unsure what to do with the VDD_SPI pin on my PCB schematic. I found an example here of someone using the ESP32-S2FH4:

https://www.wemos.cc/en/latest/_static/ ... v1.0.0.pdf

They have the VDD_SPI pin connected to a global net that is unused anywhere else. Can someone please explain what I need to do? like can I just leave this pin floating as I don't need external flash for this IC? Thank you

Here's the ESP32 family data sheet if that helps:
https://www.espressif.com/sites/default ... eet_en.pdf

You want to add some decoupling capacitors to that pin (hardware reference guidelines doc suggests an 1u and an 100n) but nothing more. In other words: the schematic is correct, aside from those caps, you don't need to connect that pin anywhere.

Thanks for the response. So what's the point in the decoupling caps if the pin is unused?

It's not unused per se: it's still connected to the flash chip, but in this case the flash chip is embedded in the package. (See the image here, the bit with the blue rectangles is the flash chip which is put on top of the ESP32-C2 silicon; the ESP32-S2 with integrated flash is similar). As such, it still needs decoupling as we can't really put those capacitors inside that type of package as well.