How to use LittleFS on ESP32 with vsCode+platfromIO

As a suplement of this tutorial How to use LittleFS on ESP8266 I follows some reference and examples to build this blog.

Get to konw some basic introductions about SPIFFS and LittleFS on ESP8266 and ESP32 is necessary for a noob.

Note: Most of the functions for SPIFFS operations are compatible for LittleFS.

follow the tutorials one by one:

- SPIFFS for ESP8266
- SPIFFS for ESP32
- LittleFS for ESP8266
- LittleFS for ESP32

LittleFS is newly introduced into ESP32 SDK (Aug 2021) . By May2022, the default ESP32-arduino SDK (arduino-esp32 core) usd by platformIO is version 1.0.3, which is not supporting LittleFS originally. You’ll meet that the <LittleFS.h> is missing.

Next, discuss how to upload littleFS files with platform IO.

2. ESP32: Build and upload LittleFS filesystem image with platformIO

Ref: ESP32 integrated littleFS file system

Different version of arduino-esp32 core will have different way of using littlefs file system. So, in vsCode+platformIO IDE, framework of Arduino, on ESP32, using littlefs is a little more tricky.

we have two ways (two versions of core), you can select:

way1: Create a ESP32 proj in platformio, rely on default arduino-esp32 core (v1.x.x) —

in arduino-esp32 core of version 1.0.x, there is no library for littleFS. while this repo offers.

• create a project with platformio.inias below

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 230400
board_build.filesystem = littlefs

• create data folder under root of project

• create /data/test1.txt file with random letters.

• Create /data/subfolder/test2.txt with random letters.

• in platfomio’s task list, run Build Filesystem Image task. You may see:

  > Executing task: platformio run --target buildfs --environment esp32dev <
  
  Processing esp32dev (platform: espressif32; board: esp32dev; framework: arduino)
  ...
  ...
  ...
  Building in release mode
  Building FS image from 'data' directory to .pio/build/esp32dev/littlefs.bin
  /subfolder/test2.txt
  /test1.txt
  

• in platformio’s task list, run Upload Filesystem Image

• use the code from library example, build and upload to ESP32 board to test. If you see subfolder in the output under DIR list. It looks like littleFS is rightly built.

  Listing directory: /
  Listing directory: /
    FILE: /file1.txt  SIZE: 3  LAST WRITE: 2020-10-06 15:10:33
    DIR : subfolder  LAST WRITE: 2022-05-19 05:33:49
    DIR : /testfolder  LAST WRITE: 2020-10-06 15:10:33
    FILE: test1.txt  SIZE: 55  LAST WRITE: 2022-05-19 05:33:56
  Creating Dir: /mydir
  Creating Dir: /mydir
  Dir created
  Dir created
  Writing file: /mydir/hello2.txt
  Writing file: /mydir/hello2.txt
  - file written
  
  ...
  

way2: Using LittleFS for ESP32 with platformio on arduino-esp32 core of version 2.0.3 —

1. to use the arduino-esp32 core of version 2.0.x in platformIO, add/replace the platformio.ini file with two lines below:

   platform = https://github.com/platformio/platform-espressif32.git#feature/arduino-upstream
   platform_packages = framework-arduinoespressif32 @ https://github.com/espressif/arduino-esp32.git#2.0.1
   

2. create ‘data’ folder at proj root

3. Create ‘subfolder’ under ‘data’ : <proj. root>/data/subfolder, and put random files into data and subfolder like:

   /data/test.txt
   /data/subfolder/test2.txt
   

4. Put mklittlefs in root of proj.. download that exe for your OS from a zipped binary here.

5. put the littlefsbuilder.py in proj. root.

   Add to platformio.ini: extra_scripts = littlefsbuilder.py

   This py makes PlatformIO believe it has created a SPIFFS.

   My littlefsbuilder.py (OSX for mac) :

   Import("env")
   print(" <littlefsbuilder.py>: make platformIO believes that it crates a SPIFFS filesystem.")
   env.Replace( MKSPIFFSTOOL=env.get("PROJECT_DIR") + '/mklittlefs' )  # PlatformIO now believes it has actually created a SPIFFS
   

6. run Build filesystem and Upload filesystem in platformIO task list.

   terminal log for build filesystem:

   Building in release mode
    <littlefsbuilder.py>: make platformIO believes that it crates a SPIFFS filesystem.
   Building SPIFFS image from 'data' directory to .pio/build/esp32dev/spiffs.bin
   /subfolder/test2.txt
   /test.txt
   

7. For more details, follow this readme file: README.md . and refer README in this repo .

8. compare the diff on diff filesystems:

9.