1.9 LittleFS Filesystem using NVM Media
This application shows an example of implementing a LittleFS disk in the device internal Flash memory.
Description
File System Operations on NVM:
- Application places a LittleFS disk image in the internal Flash memory (NVM)
- During execution, the application first opens an existing file named
FILE.TXT and performs following file system related
operations:
- SYS_FS_FileStat
- SYS_FS_FileSize
- SYS_FS_FileSeek
- SYS_FS_FileEOF
- It tries to read the file and checks if string “Data” is present. If present it continues to next step or it fails the application
- Finally, the string “Hello World” is written to this file. The string is then read and compared with the string that was written to the file. If the string compare is successful, An LED indication is provided
File System layer uses:
- Memory driver to communicate with underlying NVM media
Downloading and Building the Application
To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.
Path of the application within the repository is apps/fs/nvm_littlefs/firmware.
To build the application, refer to the following table and open the project using its IDE.
| Project Name | Description |
|---|---|
| pic32mz_w1_curiosity.X | MPLABX project for PIC32MZ W1 Curiosity Board |
Setting Up the Hardware
The following table shows the target hardware for the application projects.
| Project Name | Description |
|---|---|
| pic32mz_w1_curiosity.X | PIC32MZ W1 Curiosity Board |
Setting Up PIC32MZ W1 Curiosity Board
- Connect micro USB cable to the ‘USB Debug’ connector (J302) on the board to the computer
Running the Application
- Build and program the application using its IDE
- Press Switch to start the file operations
- The LED is turned ON when the File FILE.TXT has the app data “Hello World” written in it
| Board | Switch Name | LED Name |
|---|---|---|
| PIC32MZ W1 Curiosity Board | SW200 | RED LED |
Generate LittleFS image and convert to C file to store in NVM
If you want to generate a LittleFS image to store in NVM, you can follow below steps:
- Download the prebuild mklittlefs tool
- On Windows PC, unzip i686-w64-mingw32-mklittlefs-1ee4877.zip (If you are using other OS PC, you can unzip other prebuild tool)
- Go to directory i686-w64-mingw32-mklittlefs-1ee4877/mklittlefs/
- create directory src_folder
- Copy the files or directory of the generated image to the path i686-w64-mingw32-mklittlefs-1ee4877/mklittlefs/src_folder
- Run command mklittlefs.exe -c src_folder -d 5 -a -b 512 -p 16 -s 65536 lfs_image.img (The image size is 64KB for this command)
- lfs_imag.img is generated
- Use bin2c to convert lfs_image.img to C file
- Replace the generated array variable to array LFS_IMAGE in \firmware\src\nvm_disk_images.c