eMMC

The phyCORE-AM65x SOM comes with a 4GB eMMC by default and can be optionally populated with a larger eMMC storage device up to 32 GB in size. This guide provides steps to mount, read from, and write to the phyCORE-AM65x on board eMMC.

Note

In order to follow this guide your phyCORE-AM65x development kit must be booting from SD card.

Viewing available eMMC partition information

Warning

Be careful with the fdisk command. You can accidentally delete the contents of other memory devices connected to the system.

  • The eMMC corresponds to /dev/mmcblk0 in Linux. You can verify the eMMC partitions by using the following command:

    Target (Linux)
    fdisk -l /dev/mmcblk0

  • An example of a list of partitions on an eMMC device is shown below:

    Expected Output
    root@am65xx-phycore-rdk:~# fdisk -l /dev/mmcblk0
Disk /dev/mmcblk0: 3.6 GiB, 3850371072 bytes, 7520256 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: F7B887C4-C9D8-4C35-9E70-566EE5F80C56

Device         Start     End Sectors  Size Type
/dev/mmcblk0p1    34 7520222 7520189  3.6G Microsoft basic data

Mounting the eMMC

  • In order to read and write to the eMMC, you will need to create a directory; then mount the desired partition to that directory. Follow the steps below to mount partition 1 of the eMMC:

    Target (Linux)
    mkdir temp
mount /dev/mmcblk0p1 temp/

  • Use the following command to see the contents of the mounted memory device.

    Target (Linux)
    ls temp

    An example of what the contents would look like is provided below:

    Expected Output
    root@am65xx-phycore-rdk:~# ls temp
bin         dev         home        lib         media       opt         run         srv         tmp         var
boot        etc         include     lost+found  mnt         proc        sbin        sys         usr         www

Writing to the eMMC

  • You can write to the eMMC by using the copy or move commands, just like in Linux.

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

  • Use the following command again to see the contents of the eMMC:

    Target (Linux)
    ls temp

    An example of what the contents now look like following the copy is provided below:

    Expected Output
    root@am65xx-phycore-rdk:~# ls temp
bin         dev         home        lib         media       opt         run         srv         test.txt    usr         www
boot        etc         include     lost+found  mnt         proc        sbin        sys         tmp         var

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