Getting Started With Zephyr: Saving Data To Files

Mohammed Billoo

Still RelevantIntermediate

In this blog post, I show how to implement a Zephyr application to mount a microSD card, create a new file on the microSD card, and write data to it. The lessons learned from such an application can be helpful for devices out in the field that need to write data to off-board memory periodically, especially in cases where Internet access may be sporadic.

Summary

This blog post walks through implementing a Zephyr application that mounts a microSD card, creates a file, and writes data to it. The reader will learn practical steps and antipatterns for reliable off-board storage on Zephyr-powered devices, useful for field deployments with intermittent connectivity.

Key Takeaways

Enable and configure SD/MMC and filesystem drivers in Zephyr using DeviceTree and Kconfig
Mount a microSD card and handle common mount/driver errors in Zephyr
Create, write, flush, and close files using Zephyr's filesystem APIs to ensure data integrity
Implement safe-write patterns and basic error/power-loss handling for periodic data logging

Who Should Read This

Embedded firmware engineers or advanced hobbyists with basic RTOS knowledge who need to implement reliable off-board storage or data logging on Zephyr-based devices.

Still RelevantIntermediate