SD Card
========

This guide will show you how to use and access the SD card interface on the phyCORE-i.MX8X development kit carrier board. In order to follow this guide, you will have to boot from the on-board eMMC. See the flash from :ref:`flasheMMC-8x` for more information.

.. image:: ../../images/phycore-imx8x/pcm-065_sdcard.webp
  :width: 800px

Requirements
--------------

* 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 Transfering Media from Host)

* SD card reader (operational under Linux) (Only for Transfering Media from Host)

Hardware Setup
---------------

* Make sure the boot switch (S10) is set to boot from eMMC and power on the development kit.

  .. image:: ../../images/phycore-imx8x/pcm-065_emmc-bootswitch.webp
    :width: 500px

Mounting the SD Card
----------------------

* When an external SD Card is inserted into the development kit it is not mounted by default. It will be available as "/dev/mmcblk1".

  .. code-block:: none
    :caption: Expected Output

    [  368.709002] mmc1: host does not support reading read-only switch, assuming write-enable
    [  368.721029] mmc1: new high speed SDHC card at address 1234
    [  368.727454] mmcblk1: mmc1:1234 SA04G 3.64 GiB
    [  368.734130]  mmcblk1: p1

* Create a temporary directory and mount the sd card.

  .. code-block:: none
    :caption: Target (Linux)

    mkdir /home/root/temp
    mount /dev/mmcblk1p1 /home/root/temp

Write to SD Card
-----------------

* Create a test file in your root directory and then copy the file to the SD Card.

  .. code-block:: none
    :caption: Target (Linux)

    echo "Hello World" > test.txt
    cp test.txt /home/root/temp/

Read from SD Card
------------------

* Copy the test file back from the SD Card to your root directory.

  .. code-block:: none
    :caption: Target (Linux)

    cp /home/root/temp/test.txt read.txt

* Make sure the data was not corrupted during the file transfers using md5sum.

  .. code-block:: none
    :caption: Target (Linux)

    md5sum /home/root/test.txt /home/root/read.txt

  .. code-block:: none
    :caption: Expected Output

    e59ff97941044f85df5297e1c302d260  test.txt
    e59ff97941044f85df5297e1c302d260  read.txt

Unmount the SD Card
--------------------

.. warning:: **Make sure the SD Card is unmounted prior to physically disconnecting it.**

             Failure to do so may result in loss of data and corruption of files

.. code-block:: none
  :caption: Target (Linux)

  umount /home/root/temp