Hardware Development


ESP32-S2 Modules

For a list of ESP32-S2 modules please check the Modules section on Espressif’s official website.

To review module reference designs please check the Documentation section on Espressif’s official website.

ESP32-S2 Development Boards

For a list of the latest designs of ESP32-S2 boards please check the Development Boards section on Espressif’s official website.

Download Guidelines

You can download firmware to ESP32-S2 via UART.

To download via UART:

  1. Before the download, make sure to set the chip or module to Joint Download Boot mode, according to Table Boot Mode Control.

  2. Power up the chip or module and check the log via the UART0 serial port. If the log shows “waiting for download”, the chip or module has entered Joint Download Boot mode.

  3. Download your firmware into flash via UART using the Flash Download Tool.

  4. After the firmware has been downloaded, pull GPIO0 high or leave it floating to make sure that the chip or module enters SPI Boot mode.

  5. Power up the chip or module again. The chip will read and execute the new firmware during initialization.


  • It is advised to download the firmware only after the “waiting for download” log shows via serial ports.

  • Serial tools cannot be used simultaneously with the Flash Download Tool on one com port.

  • The USB auto-download will be disabled if the following conditions occur in the application, where it will be necessary to set the chip or module to Joint Download Boot mode first by configuring the strapping pin.

    • USB PHY is disabled by the application;

    • USB is secondary developed for other USB functions, e.g., USB host, USB standard device;

    • USB IOs are configured to other peripherals, such as UART and LEDC.

  • It is recommended that the user retains control of the strapping pins to avoid the USB download function not being available in case of the above scenario.