Introduction to Python and Microcontrollers

ESP32-S3 WROOM Setup — macOS

1. Install the CH343 USB Driver

The ESP32-S3 WROOM uses the CH343 chip for USB-to-serial communication. You must install its driver before your Mac can communicate with the board.

  1. Unzip the driver CH34XSER_MAC.ZIP
  2. If using MacOS 11 or higher open CH34xVCPDriver.dmg

    If using an older version of MacOS ask for help

  3. Allow applications from App Store & Known Developers

    Go to System Settings -> Privacy & Security then scroll down to find setting alt text

  4. Drag the CH34xVCPDriver application to the Applications folder
  5. Go to the Applications folder and open the app

    Click Open when asked if you want to open the app

  6. Click the Install button in the app window

    Click OK when asked if you want to install a new driver extension

  7. Enable Driver Extension in System Settings
    • Go to System Settings -> General -> Login Items & Extensions
    • Click the i in circle next to CH34xVCPDriver
    • Click the slider and enter your password when prompted enable driver
    • Click Done

2. Install Thonny IDE

Thonny is the recommended Python IDE for programming the ESP32-S3 with MicroPython.

  1. Download the installer: https://github.com/thonny/thonny/releases/download/v5.0.0/thonny-5.0.0-x64.pkg
  2. Double-click the .pkg file and follow the installation prompts.
  3. Once installed, open Thonny from your Applications folder

3. Flash MicroPython Firmware

The ESP32-S3 needs MicroPython firmware flashed onto it before you can run Python programs.

The firmware is located in setup/Python_Firmware/ESP32_GENERIC_S3-SPIRAM_OCT-20250809-v1.26.0.bin

How To connect board via USB

Flash the firmware:

  1. Connect the ESP32-S3 WROOM to your Mac via USB cable.
    • Use the right hand USB3 connection on the microcontroller
    • If the blue light is blinking when connected press the reset (RST) button
  2. Open Finder and navigate to setup folder.
  3. Right-click the Python_Firmware folder and select New Terminal at Folder.
  4. In the Terminal, run: 
    python3 mac.py
  5. Wait for the firmware to finish burning. A completion message will appear when done.

4. Configure Thonny

  1. Open Thonny.
  2. Go to View → enable Files and Shell.
  3. Go to Run → Configure interpreter.
  4. Set the interpreter to MicroPython (ESP32).
  5. Set the port to the USB serial port for the ESP32-S3 (it will appear as something like /dev/cu.usbserial-XXXX or /dev/cu.wchusbserial-XXXX).
  6. Click OK.
  7. Press Stop sign to reset

6. Test the Connection

In the Shell panel at the bottom of Thonny, type:

print('hello world')

Press Enter. If hello world is printed back, the connection is working correctly.

7. Running Code

Run Online (while connected to Mac)

  1. In Thonny, click Open… → This computer.
  2. Navigate to 01_first_examples/code/HelloWorld.py
  3. Click Run current script (green play button).

Note: If you press the reset button on the ESP32-S3 while running online, the code will not restart automatically.

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