1.2 FAT Filesystem Using SDMMC Media

This application shows an example of using the MPLAB Harmony File System to access and modify the contents of a SD card using the SDMMC driver.

Description

File System Operations on the SD Card:

  • Application opens a file named FILE_TOO_LONG_NAME_EXAMPLE_123.JPG in the root directory of the SD card and reads its content into memory
    • The image file could be any arbitrary JPEG (image) file chosen by the user and then renamed to FILE_TOO_LONG_NAME_EXAMPLE_123.JPG
  • Application creates directory named Dir1 in the root directory
  • Application creates a new file named FILE_TOO_LONG_NAME_EXAMPLE_123.JPG inside Dir1
  • Application copies the content from step 1 into this newly created file

The reason for choosing a JPEG file for test purposes is that the duplicate file, Dir1/FILE_TOO_LONG_NAME_EXAMPLE_123.JPG created by the demonstration could be easily verified for correctness. If the new file inside Dir1 opens for viewing on the computer and matches to original image, the test is deemed to have passed. Otherwise, if the file does not open (i.e., is corrupted), the test will be considered to have failed.

Note: Since the application creates a directory named Dir1, it is important that the folder with the same name does not exist on the SD card. If a directory named Dir1 is already present on the SD card, the application will fail.

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/sdmmc_fat.

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

Project NameDescription
sam_a7d65_curiosity.XMPLAB X project for SAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.XMPLAB X project for SAMA7D65 Curiosity Pro Board

Setting Up AT91Bootstrap Loader

To load the application binary onto the target device, it is necessary to use at91bootstrap loader. Refer to the at91bootstrap loader documentation for details on how to configure, build, and run bootstrap loader project and use it to bootstrap the application binaries.

Setting Up the Hardware

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

Project NameDescription
sam_a7d65_curiosity.XSAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.XSAMA7D65 Curiosity Pro Board

Setting Up SAMA7D65 Curiosity Board

Additional Hardware Required
  • SD card with FAT32 file system
Setting Up the SD Card
  • Create a new JPEG file in the SD Card with name FILE_TOO_LONG_NAME_EXAMPLE_123.JPG
Setting Up the Board
  • Connect the USBA port J3 on the board to the computer using a USB Type-C® cable (to power the board)
  • Use SDMMC1 (J10) slot

Setting Up SAMA7D65 Curiosity Pro Board

Additional Hardware Required
  • SD Card with FAT32 file system
Setting Up the SD Card
  • Create a new JPEG file in the SD Card with name FILE_TOO_LONG_NAME_EXAMPLE_123.JPG
Setting Up the Board
  • Connect the USBA port J1 on the board to the computer using a USB Type-C cable (to power the board)
  • Use SDMMC1 (J42) slot

Running the Application

  1. Build the application using its IDE.
  2. The LED is turned ON if there was no error during creating the directory and copying the file into it.
Refer to the following table for LED name:
BoardLED Name
SAMA7D65 Curiosity BoardRGB_LED (Green)
SAMA7D65 Curiosity Pro BoardRGB_LED (Green)