1.4 FAT Filesystem using NVM and SST26 Media

This application shows an example of using the MPLAB Harmony File System to access multiple files across multiple media (NVM, SQI FLASH).

Description

File System Operations on NVM:

  • Application places a FAT disk image consisting of a Master Boot Record (MBR) sector, Logical Boot Sector, File allocation Table, and Root Directory Area 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
  • 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

File System Operations on the On-Board SST26 Flash Memory:

  • Performs a SYS_FS_FormatDisk
  • Opens a newfile.txt on the SST26 flash
  • Write and reads back 4KB of data on newfile.txt
  • Verifies the Data Read back

File system layer uses:

  • One instance of the Memory driver is used to communicate with underlying NVM media
  • One instance of the Memory driver is used to communicate with the On-Board SQI Flash memory

The Application Consists of three tasks which are called in RTOS Thread Context:

  1. APP_SST26_Tasks():
    • Performs File Operations on SQI Flash memory
  2. APP_NVM_Tasks():
    • Performs File Operations on NVM
  3. APP_MONITOR_Tasks():
    • Monitors the state of above two Tasks

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_sqi_fat/firmware.

To build the application, refer to the following table and open the project using its IDE.

Project NameDescription
pic32mz_ef_sk_freertos.XMPLABX project for PIC32MZ Embedded Connectivity with FPU (EF) Starter Kit

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameDescription
pic32mz_ef_sk_freertos.XPIC32MZ Embedded Connectivity with FPU (EF) Starter Kit

Setting Up PIC32MZ Embedded Connectivity with FPU (EF) Starter Kit

  • Connect the Debug USB port on the board to the computer using a mini USB cable

Running the Application

  1. Build and program the application using its IDE
  2. The LED toggles when the following criteria is satisfied.
    • For NVM media:
      • File “FILE.TXT” has the app data “Hello World” written in it
    • For SST26 media:
      • 4KB of data has successfully been written and read back from file “newfile.txt”
Refer to the following table for LED name:
BoardLED Name
PIC32MZ Embedded Connectivity with FPU (EF) Starter KitLED3