This user guide will help you get started with ESP32-S3-USB-Bridge and will also provide more in-depth information.

The document consists of the following sections:

Board Overview

ESP32-S3-USB-Bridge is a development board based on ESP32-S3.

  • The usb_wireless_bridge example can be used to establish a bridge between a computer and the target chip. It can emulate a USB composite device and supports multiple functions:

    • USB-to-UART Bridge: realizes serial data transmission and reception between the computer and the target chip.

    • JTAG Adapter: realizes duplex JTAG communication between the computer and the target chip.

    • MSC Storage Device: updates firmware by storing the UF2 firmware files in the USB storage device of the board.

    • Wireless Bridge: realizes wireless flashing and wireless serial data transmission and reception through ESP-NOW.

ESP32-S3-USB-Bridge Type-C Connection

ESP32-S3-USB-Bridge Type-C Connection

The development board also supports a USB Type-A interface that is convenient for replacement.

ESP32-S3-USB-Bridge Type-A Connection

ESP32-S3-USB-Bridge Type-A Connection

Feature List

The main features of the board are listed below:

  • Module Embedded: ESP32-S3-MINI-1 module with 4 MB flash and 2 MB PSRAM

  • LED Indicators: on-board WS2812 LED indicator with two serial data LED indicators

  • USB: on-board USB-to-UART bridge and JTAG adapter, with support for USB download/debugging

Block Diagram

The block diagram below shows the components of ESP32-S3-USB-Bridge and their interconnections.

ESP32-S3-USB-Bridge Block Diagram (Click to Enlarge)

ESP32-S3-USB-Bridge Block Diagram (Click to Enlarge)

Description of Components

ESP32-S3-USB-Bridge is a rather compact development board, with a dimension of 23.3 mm * 31.5 mm. It integrates the ESP32-S3-MINI-1 module and offers a 12-pin expansion connector.

ESP32-S3-USB-Bridge - Front (Click to Enlarge)

ESP32-S3-USB-Bridge - Front (Click to Enlarge)

The key components of the board are described in a clockwise direction.

Key Component


ESP32-S3-MINI-1-N4R2 Module

ESP32-S3-MINI-1-N4R2 is a generic Wi-Fi + Bluetooth LE MCU module that is built around the ESP32-S3 series of SoCs. It is integrated with 4 MB flash and 2 MB PSRAM. On top of a rich set of peripherals, the acceleration for neural network computing and signal processing workloads provided by the SoC makes the module an ideal choice for a wide variety of application scenarios related to Artificial Intelligence of Things (AIoT).

TX/RX Indicator

Indicates transmit and receive status of serial data.

Expansion Connector

Provides connections for JTAG pins, serial pins, TX/RX pins, Boot pins, Reset pins, and power supply pins.

Reset Button

Connects the Reset button on the target chip and IO8 on the module. Press this button to reset the target chip.

USB-to-USB Port

Provides power to the entire system. Used for USB communication between the PC and the ESP32-S3-MINI-1 module.

Boot Button

Connects the Boot button on the target chip and IO9 on the module. Holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then you can upload firmware through the serial port or USB.

ESP32-S3-USB-Bridge - Back (Click to Enlarge)

ESP32-S3-USB-Bridge - Back (Click to Enlarge)

Key Component


5 V to 3.3 V

Converts the USB voltage to 3.3 V for powering the ESP32-S3-MINI-1 module.

Module Boot Button

Connects IO0 on the module. After holding down the Boot button and powering up the development board again, the board enters the download mode and initiates the firmware upload mode for uploading firmware.


Connects IO42 on the module and indicates the current state of the development board.

Software Support

Development of applications for ESP32-S3-USB-Bridge can be done using ESP-IDF framework. ESP-IDF is a FreeRTOS-based SoC development framework with several components including LCD, ADC, RMT, and SPI. An example is provided for ESP32-S3-LCD-EV-Board under the folder Examples . You can configure project options by entering menuconfig in the example directory.


  • The current supported ESP-IDF version is release/5.0.

  • To prevent the default firmware from being replaced, please avoid pressing and holding the module’s own Boot button while powering the board up/down.

Start Application Development

This section provides instructions on how to do hardware and software setup and flash firmware onto the board to develop your own application.

Required Hardware

  • 1 x ESP32-S3-USB-Bridge

  • 1 x LCD subboard

  • 1 x USB 2.0 cable (standard Type-A to Type-C)

  • 1 x PC (Windows, Linux, or macOS)


Please make sure to use the appropriate USB cable. Some cables can only be used for charging, not for data transfer or program flashing.

Hardware Setup

Prepare the board for loading of the first sample application:

  1. Plug in the USB cable to connect the PC with the USB port on the board.

  2. Make sure the board is in the download mode.

  3. The LED lights up indicating the completion of flashing.

Now the board is ready for software setup.

Software Setup

Please proceed to Get Started, where Section Installation will quickly help you set up the development environment.

For more software information on developing applications, please go to Software Support.

Hardware Reference

This section provides more detailed information about the board’s hardware.

GPIO Allocation

The table below provides the GPIO allocation of the ESP32-S3-MINI-1 module and its 12-pin expansion connector, which is used to control specific components or functions on the development board as well as the externally connected target chip.

ESP32-S3-MINI-1 and Expansion Connector GPIO Allocation


Pin Name







Power supply



Module boot button for entering download mode which can also be used as a key input pin



JTAG pin TDO for test data output



JTAG pin TDI for test data input



JTAG pin TCK for synchronized test data transfer



JTAG pin TMS for test mode configuration



The Reset pin connecting to the target chip, which sets the target chip to low level when pressed



The Boot pin connecting to the target chip, which sets the target chip to low level when pressed









RX connecting to the UART TX pin of the target chip



TX connecting to the UART RX pin of the target chip



WS2812 control pin


Pin 3 to Pin 14 are the corresponding pins of the 12-pin expansion connector. Apart from the features in the above table, all these IO pins support to be configured for other purposes. Note that GPIO5 and GPIO8 should be connected to external keys.

Power Distribution

Power Supply over USB

There are two ways to power the development board via the USB power port:

  • Via the Type-A port

ESP32-S3-USB-Bridge -Type-A Power Supply

ESP32-S3-USB-Bridge - Type-A Power Supply

  • Via the Type-C port

ESP32-S3-USB-Bridge - Type-C Power Supply

ESP32-S3-USB-Bridge - Type-C Power Supply

Voltage Conversion Circuit

The ESP32-S3-USB-Bridge supports converting 5 V to 3.3 V for the module.

ESP32-S3-USB-Bridge - Voltage Conversion

ESP32-S3-USB-Bridge - Voltage Conversion

Hardware Setup Options

Automatic Download

Press the Boot button on the module and re-power up the board, then release the Boot button to allow the board to enter the download mode.

Hardware Revision Details

No previous revisions.

Sample Request

This board has been open-sourced to OSHWHub. Please sample it according to your needs.