esp-idf/examples/storage/littlefs

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-S2	ESP32-S3

About LittleFS

LittleFS is a file system designed for small devices like microcontrollers and embedded systems. It helps these devices manage and store data efficiently.

• LittleFS is specifically built to be lightweight and requires less storage space and processing power. It takes up very little memory, which is important for small devices with limited resources.
• It has features that ensure data integrity and reliability, so the files stored on the device are less likely to get corrupted or lost. In a nutshell, LittleFS is a specialized file system that helps small devices effectively handle and store data, allowing them to perform tasks efficiently with minimal resources.

License

The littlefs is provided under the BSD-3-Clause license. Please refer littlefs license for more details.

LittleFS example

(See the README.md file in the upper level 'examples' directory for more information about examples.)

littlefs component is managed in ESP-IDF using IDF component manager. This example uses a littlefs port for ESP-IDF littlefs for which upstream repository is esp_littlefs.

LittleFS partition generator is invoked from CMake build system. We use littlefs_create_partition_image in main/CMakeLists.txt to generate the partition image and flash it to the device at build time.

Note: Currently Windows does not support LittleFS partition generation feature.

This example demonstrates how to use LittleFS with ESP32. Example does the following steps:

1. Use an "all-in-one" esp_vfs_littlefs_register function to:
   • initialize LittleFS,
   • mount LittleFS filesystem using LittleFS library (and format, if the filesystem can not be mounted),
   • register LittleFS filesystem in VFS, enabling C standard library and POSIX functions to be used.
2. Create a file using fopen and write to it using fprintf.
3. Rename the file. Before renaming, check if destination file already exists using stat function, and remove it using unlink function.
4. Open renamed file for reading, read back the line, and print it to the terminal.

LittleFS partition size is set in partitions_demo_esp_littlefs.csv file. See Partition Tables documentation for more information.

How to use example

Hardware required

This example does not require any special hardware, and can be run on any common development board.

Build and flash

Replace PORT with serial port name:

idf.py -p PORT flash monitor

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example output

Here is an example console output. In this case format_if_mount_failed parameter was set to true in the source code. LittleFS was unformatted, so the initial mount has failed. LittleFS was then formatted, and mounted again.

I (264) esp_littlefs: Initializing LittleFS
I (274) esp_littlefs: Partition size: total: 983040, used: 12288
I (274) esp_littlefs: Opening file
I (344) esp_littlefs: File written
I (344) esp_littlefs: Renaming file
I (354) esp_littlefs: Reading file
I (354) esp_littlefs: Read from file: 'Hello World!'
I (354) esp_littlefs: Reading from flashed filesystem example.txt
I (364) esp_littlefs: Read from file: 'Example text to compile into a LittleFS disk image to be flashed to the ESP device.'
I (374) esp_littlefs: LittleFS unmounted
I (374) main_task: Returned from app_main()

To erase the contents of LittleFS partition, run idf.py erase-flash command. Then upload the example again as described above.

Here you can find performance results for LittleFS, SPIFFS and FATFS for your reference.