microSD Card Example¶

Description¶

The microSD Card Example demonstrates the use of a microSD memory card using the SD Card library and the FatFs file system library.

The example initializes the card and performs basic operations like mounting the FAT volume, writing and reading the example file.

The microSD Card is connected to the nRF52840 chip over a SPI bus. The table below shows the connections of each pin of the microSD Card:

Before you start coding, the Python Interpreter should be installed on the nRF52840 M.2 module correctly:

Install Python Interpreter

Run the code¶

Run the microSD Card Example by performing the following steps:

1. Power down the board

2. Insert a FAT formatted microSD card into the microSD slot

3. Connect the Module USB port to your PC as shown in the figure below. A disk drive called CIRCUITPY should be automatically detected by the computer:

   

4. Open the code.py file on your CIRCUITPY drive, then copy and paste the following code. Your code will run as soon as the file is done saving.

   # SD card usage
   import board
   import digitalio
   import displayio
   import sdcard
   import storage
   
   displayio.release_displays()
   spi = board.SPI()
   cs = digitalio.DigitalInOut(board.P7)
   sd = sdcard.SDCard(spi, cs)
   vfs = storage.VfsFat(sd)
   storage.mount(vfs, "/sd")
   print("microSD Card mounted.")
   
   # write to sd card
   print("Writing to file /sd/test.txt ...")
   with open("/sd/test.txt", "w") as f:
       f.write("This is the written string.\n")
   
   # read from sd card
   print("Reading from file /sd/test.txt ...")
   with open("/sd/test.txt", "r") as f:
       data = f.read()
       print(data)
   

5. Run a terminal application like PuTTY or screen:

   screen /dev/cu.usbmodem14102 115200
   

6. Save the code and observe the output of the terminal:

   

Create an Issue¶

Interested in contributing to this project? Want to report a bug? Feel free to click here:

Create an Issue