ESP32-P4: How to connect VDD_FLASHIO & VDDO_FLASH

The VDD_FLASHIO and VDDO_FLASH pins on the ESP32-P4 microcontroller are used to supply power to the flash memory and the ESP32-P4 internal flash IO circuitry.

Typically you should connect VDD_FLASHIO and VDDO_FLASH together but not connect them to the main 3.3V or 1.8V power supply.

The VDDO_FLASH pin is an output of the internal LDO regulator inside the ESP32-P4 chip. By default, it is configured to output 3.3V to power the flash memory, but it can be configured to output 1.8V via E-Fuses if your flash memory requires 1.8V instead of 3.3V. Note that when first starting up the ESP32-P4, the VDDO_FLASH pin will output 3.3V until the programmer configures it to output 1.8V if needed, so it might damage 1.8V only flash memory if you connect it directly to the VDDO_FLASH pin.

Consequently, you should typically connect both VDD_FLASHIO and VDDO_FLASH to the power supply pin of your flash memory chip.

Generally, I recommend using 3.3V flash memory with the ESP32-P4 for ease of use.

The permissible operating voltage for the VDD_FLASHIO pin is 1.65V..1.95V for 1.8V flash memory and 3.0V..3.6V for 3.3V flash memory (absolute maximum rating of 3.6V). Supplying a higher voltage than 3.6V may destroy the chip.

You must place 100nF and 1uF capacitors near the VDD_FLASHIO pin.

Source: ESP32-P4 hardware design guide