SD Card

The phyCORE-AM65x SOM brings out a 4-bit wide MMC data bus to the standard SDHC card slot at X13. Power to the card slot is supplied by inserting the appropriate card into the SD/MMC1 connector, which features card detection. This interface shares a bus with the WiFi module on the SOM, but is available on the development kit as an SD card interface for external media or as a bootable interface.


In order to follow this guide, you will have to boot from the on-board eMMC. Follow this guide in order to flash eMMC

phyCORE-AM65x microSD Card Connector


  • SDHC SD card, at least 8GB for PHYTEC’s TISDK release image (Included in development kit)

  • Linux Host PC or Virtual Machine (Ubuntu recommended) (Only for transferring media from Host)

  • SD card reader (operational under Linux) (Only for transferring media from Host)


When an external SD Card is inserted, it will be available as /dev/mmcblk1 in Linux.

Mounting the SD card

  • Create a temporary directory and mount an SD card partition using the below commands:

    Target (Linux)
    mkdir /home/root/temp
    mount /dev/mmcblk1p1 /home/root/temp

Write to the SD Card

  • You can use basic Linux commands to create and write files to the SD card. Below is an example:

    Target (Linux)
    echo "Hello World" > test.txt
    cp test.txt /home/root/temp/

Read from the SD Card

  • To read what was just written to the SD card in the previous example, use the following command:

    Target (Linux)
    cp /home/root/test.txt read.txt
  • To check that the read file (read.txt) is the same as the one that was written (test.txt) you can use md5sum to compare and verify the data transfer was successful:

    Target (Linux)
    md5sum /home/root/test.txt && md5sum read.txt
  • The above command will generate a long and seemingly random string of characters for both files. This long string is called a “hash” and it uniquely identifies the files. If the hash for both files match then you can be confident that both files (down to each bit) are identical.

    Expected Output
    root@am65xx-phycore-kit:~# md5sum /home/root/test.txt && md5sum read.txt
    e59ff97941044f85df5297e1c302d260  /home/root/test.txt
    e59ff97941044f85df5297e1c302d260  read.txt

Unmounting the SD Card

  • Before unplugging the device from the development kit, make sure to unmount it in software. You can do this by running the following command:

    Target (Linux)
    umount /home/root/temp