Assignment 3: Run GUI on ESP32-S3

In this assignment, you will run the same Slint-based application on your embedded hardware — specifically targeting the ESP32-S3 microcontroller.

Supported Boards

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This workshop supports the following boards:

• M5Stack CoreS3 (recommended - touchscreen, speakers, microphone)
• ESoPe Board (SLD_C_W_S3) with RGB interface display (Schukat Smartwin concept)
• ESP32-S3-BOX-3
• ESP32-S3-LCD-EV-Board

Make sure you have a working USB connection to the board and necessary permissions set (e.g., dialout group on Linux).

Step-by-Step Instructions

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1. Connect Your Board

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Plug in your ESP32-S3-based board via USB. If you’re using the ESoPe board, ensure your ESP-Prog programmer is connected to both UART lines.

2. Choose Your Development Path

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This workshop supports both no_std (recommended) and std development approaches:

no_std Path (Recommended) ✅

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Navigate to the no_std directory for your specific board:

# For M5Stack CoreS3 (recommended)
cd slint-esp-workshop/esp32/no_std/m5stack-cores3

# For ESoPe Board
cd slint-esp-workshop/esp32/no_std/esope-sld-c-w-s3

# For ESP32-S3-BOX-3
cd slint-esp-workshop/esp32/no_std/esp32-s3-box-3

# For ESP32-S3-LCD-EV-Board
cd slint-esp-workshop/esp32/no_std/esp32-s3-lcd-ev-board

std Path (Alternative)

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If you specifically need ESP-IDF features, navigate to the std directory:

# For M5Stack CoreS3
cd slint-esp-workshop/esp32/std/m5stack-cores3

# For ESP32-S3-BOX-3
cd slint-esp-workshop/esp32/std/esp32-s3-box-3

# Other boards available in std/ directory

3. Flash the Application

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Run the following command to build and flash the application:

cargo run --release

This will compile the no_std firmware and flash it via espflash. On first use, this may take a bit longer due to compilation and linking.

Entering Bootloader Mode

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In order to flash the board, it must be in bootloader mode. If you encounter issues flashing, use the following guide:

Built-in USB UART Boards

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For boards with built-in USB-to-serial (e.g. S3-BOX-3 or LCD-Ev-Board):

1. Press and hold the BOOT button
2. While holding BOOT, press and release the RESET button
3. Release BOOT

This sequence ensures the chip enters bootloader mode.

ESoPe with ESP-Prog

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If you’re using an external ESP-Prog programmer, bootloader mode is usually handled automatically. However, after flashing is complete, you will need to press RESET manually to start the application.

What to Expect

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After the board boots, you should see the same two-tab Slint UI as on the desktop:

• The first tab displays the Slint logo
• The second tab shows a placeholder for the Wi-Fi list

If your display remains blank:

• Double-check display connections and power supply
• Ensure espflash selected the correct port
• Use verbose logging cargo run --release -v to debug

Summary

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At this point, you’ve successfully run a Slint GUI on embedded hardware. In the next assignment, we’ll expand the application to include dynamic Wi-Fi scanning.

Continue to Assignment 4 →