Minimal Build Configuration

Oct 13, 2025 by pinkandtrash.com 8 views

Introduction

The ESP-IDF (Espressif IoT Development Framework) is a popular open-source framework for developing IoT applications using ESP32 and ESP8266 microcontrollers. However, users have reported issues with the RCP (Remote Control Protocol) not working over USB, particularly when using a Raspberry Pi 3 as a bridge router. In this article, we will explore the possible causes of this issue and provide solutions to enable RCP over USB.

System Configuration

IDF Version: v5.4
Operating System: Windows
Build Method: ESP-IDF CLI
Command Line Type: Ubuntu

Expected Behavior

The expected behavior is to have the RCP example provided by ESP-IDF functioning successfully with the Raspberry Pi 3 acting as a bridge router. However, users have reported issues with the RCP not working over USB, and the Raspberry Pi 3 having issues writing to the RCP due to the USB JTAG preventing writing to the ESP from the host PC.

Troubleshooting Steps

1. Minimal Build Configuration

The user has reported that enabling USB-CDC is not possible due to the "minimal" build configuration. However, the project does not successfully build when the minimal build is off. To resolve this issue, the user can try the following:

Disable Minimal Build: In the menuconfig tool, navigate to Component config > Build Options and disable the Minimal build option.
Rebuild the Project: After disabling the minimal build, rebuild the project using the make command.

2. USB-CDC Configuration

To enable USB-CDC, the user can try the following:

Enable USB-CDC: In the menuconfig tool, navigate to Component config > USB and enable the USB CDC option.
Rebuild the Project: After enabling USB-CDC, rebuild the project using the make command.

3. Spinel Configuration

The user has reported issues with Spinel over the USB lines. To resolve this issue, the user can try the following:

Enable Spinel: In the menuconfig tool, navigate to Component config > Spinel and enable the Spinel option.
Rebuild the Project: After enabling Spinel, rebuild the project using the make command.

4. USB-to-UART Configuration

The user has reported issues with the USB-to-UART configuration. To resolve this issue, the user can try the following:

Enable USB-to-UART: In the menuconfig tool, navigate to Component config > USB and enable the USB-to-UART option.
Rebuild the Project: After enabling USB-to-UART, rebuild the project using the make command.

Conclusion

In conclusion, the RCP not working over USB issue can be resolved by disabling the minimal build configuration, enabling USB-CDC, Spinel, and USB-to-UART configurations. By following the troubleshooting steps outlined in this article, users can successfully enable RCP over USB and resolve the issues reported with the Raspberry Pi 3 acting as a bridge router.

Additional Tips and Recommendations

Use the Latest IDF Version: Ensure that the IDF version is up-to-date, as newer versions may resolve known issues.
Check the Project Configuration: Verify that the project configuration is correct and that all necessary components are enabled.
Consult the ESP-IDF Documentation: Refer to the official ESP-IDF documentation for detailed information on configuring and using the RCP protocol.

References

ESP-IDF Documentation: https://docs.espressif.com/projects/esp-idf/en/latest/
RCP Protocol Documentation: https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/remote-control-protocol/
RCP Not Working Over USB: Q&A ================================

Q: What is the RCP protocol, and how does it work?

A: The RCP (Remote Control Protocol) is a communication protocol used to control and monitor ESP32 and ESP8266 microcontrollers over a serial connection. It allows for bi-directional communication between the host PC and the microcontroller, enabling features such as remote control, debugging, and firmware updates.

Q: What are the common issues with RCP over USB?

A: Common issues with RCP over USB include:

USB JTAG preventing writing to the ESP from the host PC: This issue occurs when the USB JTAG is enabled, preventing the host PC from writing to the ESP.
RCP example not functioning with the Raspberry Pi 3: This issue occurs when the RCP example provided by ESP-IDF does not function with the Raspberry Pi 3 acting as a bridge router.
Spinel not working over the USB lines: This issue occurs when Spinel does not work over the USB lines, preventing communication between the host PC and the microcontroller.

Q: How do I troubleshoot RCP issues over USB?

A: To troubleshoot RCP issues over USB, follow these steps:

Disable Minimal Build: Disable the minimal build configuration to enable USB-CDC.
Enable USB-CDC: Enable the USB-CDC configuration to allow for bi-directional communication between the host PC and the microcontroller.
Enable Spinel: Enable the Spinel configuration to allow for communication between the host PC and the microcontroller over the USB lines.
Rebuild the Project: Rebuild the project using the make command after making changes to the configuration.

Q: What are the benefits of using RCP over USB?

A: The benefits of using RCP over USB include:

Bi-directional communication: RCP allows for bi-directional communication between the host PC and the microcontroller, enabling features such as remote control and debugging.
Firmware updates: RCP enables firmware updates to be performed over the USB connection, reducing the need for physical access to the microcontroller.
Improved debugging: RCP provides improved debugging capabilities, allowing developers to monitor and control the microcontroller over the USB connection.

Q: How do I configure RCP over USB in ESP-IDF?

A: To configure RCP over USB in ESP-IDF, follow these steps:

Enable RCP: Enable the RCP configuration in the menuconfig tool.
Configure USB-CDC: Configure the USB-CDC settings to allow for bi-directional communication between the host PC and the microcontroller.
Configure Spinel: Configure the Spinel settings to allow for communication between the host PC and the microcontroller over the USB lines.
Rebuild the Project: Rebuild the project using the make command after making changes to the configuration.

Q: What are the common mistakes when configuring RCP over USB?

A: Common mistakes when configuring RCP over USB include:

Enabling minimal build: Enabling the minimal build configuration can prevent USB-CDC from working.
Disabling USB-CDC: Disabling USB-CDC can prevent bi-directional communication between the host PC and the microcontroller.
Not enabling Spinel: Not enabling Spinel can prevent communication between the host PC and the microcontroller over the USB lines.

Conclusion

In conclusion, RCP not working over USB can be a frustrating issue, but by following the troubleshooting steps and configuring RCP correctly, developers can resolve these issues and enable bi-directional communication between the host PC and the microcontroller.