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a67d5d8 Jul 12, 2018
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SPIFFS Filesystem

Overview

SPIFFS is a file system intended for SPI NOR flash devices on embedded targets. It supports wear leveling, file system consistency checks and more.

Notes

  • Presently, spiffs does not support directories. It produces a flat structure. If SPIFFS is mounted under /spiffs creating a file with path /spiffs/tmp/myfile.txt will create a file called /tmp/myfile.txt in SPIFFS, instead of myfile.txt under directory /spiffs/tmp.
  • It is not a realtime stack. One write operation might last much longer than another.
  • Presently, it does not detect or handle bad blocks.

Tools

Host-Side tools for creating SPIFS partition images exist and one such tool is mkspiffs. You can use it to create image from a given folder and then flash that image with esptool.py

To do that you need to obtain some parameters:

  • Block Size: 4096 (standard for SPI Flash)
  • Page Size: 256 (standard for SPI Flash)
  • Image Size: Size of the partition in bytes (can be obtained from partition table)
  • Partition Offset: Starting address of the partition (can be obtained from partition table)

To pack a folder into 1 Megabyte image:

mkspiffs -c [src_folder] -b 4096 -p 256 -s 0x100000 spiffs.bin

To flash the image to ESP32 at offset 0x110000:

python esptool.py --chip esp32 --port [port] --baud [baud] write_flash -z 0x110000 spiffs.bin

See also

Application Example

An example for using SPIFFS is provided in :example:`storage/spiffs` directory. This example initializes and mounts SPIFFS partition, and writes and reads data from it using POSIX and C library APIs. See README.md file in the example directory for more information.

High level API Reference