Summary

This blog explains how to use the Apache NuttX USERLED subsystem to expose and control board LEDs from kernel and user space. Readers will learn how to enable the subsystem, map GPIOs to USERLED indices, integrate the code into board bring-up, and test/debug LED behaviors on ARM and RISC-V boards.

Key Takeaways

• Enable and configure the USERLED subsystem via NuttX Kconfig options (e.g., CONFIG_LEDS/CONFIG_USERLED).
• Map physical GPIOs to USERLED indices and implement board-level initializers to expose LEDs to the OS.
• Implement user-space LED control examples and integrate LED patterns for status/diagnostics.
• Use debugging and test techniques to validate LED behavior during bring-up and firmware updates.
• Understand how the USERLED subsystem interacts with board bring-up, device mappings, and NuttX driver conventions.

Who Should Read This

Embedded/firmware engineers (intermediate) doing NuttX board bring-up or adding LED-based diagnostics on ARM or RISC-V microcontroller boards.

Still RelevantIntermediate

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