.. _uart-57:

UART
====

The phyCORE-AM57x SoC has the capibility of supporting eight UART interfaces. The phyBOARD-AM57x delopment kit prodives access to three of these signals through interface connectors. By default, the phyCORE-AM57x development kit is configured to use UART3 (ttyS2 in the device tree) for a Linux console input and output. The UART3 signal is available through a RS232-USB connector (X18). PHYTEC recommends allocating UART3 for console access on custom designs. This guide will show you how to send serial data over the UART5 interface.

.. image:: ../../images/phycore-am57x/pb-057948_uart.png
    :width: 750px
    :alt: UART Locations

.. list-table:: UART
   :header-rows: 1

   * - UART
     - Connector
     - Character Device File
   * - UART3

       **Default Linux Console**
     - X18 (RS232-USB)
     - /dev/ttyS2
   * - UART5
     - x17 (3-pin header)
     - /dev/ttyS4
   * - UAR10
     - X26 (Wifi header)

       X28 (Expansion Header)
     - /dev/ttyS


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

* `USB to RS-232 Serial Adapter <https://www.amazon.com/Adapter-Chipset%EF%BC%8CRS232-USB-Serial-Converter-Windows/dp/B0759HSLP1/ref=sr_1_1_sspa?hvadid=557588407367&hvdev=c&hvlocphy=9033314&hvnetw=g&hvqmt=e&hvrand=6761798776606774634&hvtargid=kwd-4990307659&hydadcr=18038_13447332&keywords=usb%2Bto%2Bserial%2Brs232%2Badapter&qid=1681511534&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyNjEwUEMzNkZNQ1IzJmVuY3J5cHRlZElkPUEwNzk2ODY1MU1CV0hNRURHUEc1SiZlbmNyeXB0ZWRBZElkPUEwMzAzMzIzSldNTUNEWU1YRUU2JndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1>`_

* `3x F/F Jumper Wire <https://www.amazon.com/Elegoo-EL-CP-004-Multicolored-Breadboard-arduino/dp/B01EV70C78/ref=sr_1_2_sspa?crid=18W6C4PQ0DDEV&keywords=male+female+jumper+wires&qid=1704499871&s=industrial&sprefix=male+female+jumper+wire%2Cindustrial%2C127&sr=1-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1>`_


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

* Power off and remove the power supply from the development kit.

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

    poweroff

* Connect the the RS232-USB to one side of the F/F jumper cables.

* Then connect the F/F jumpers to the 3-pin header X17.

  .. image:: ../../images/phycore-am57x/pb-057948_uart-x17-pinout.png
    :width: 350px
  .. image:: ../../images/phycore-am57x/pb-057948_uart-x17-pin1.png
    :width: 500px

* Open your Host system's Device Manager and expand Ports (COM & LPT).

  .. note::
     Windows systems can press the Windows key, type "device manager" and press ENTER.

* Connect the USB end of the RS232-USB cable to your Host machine.

* Take note of any new device names that appear under "Ports". You'll need the COM port device number in the next steps.

   .. image:: ../../images/phycore-am57x/pb-057948_uart-device-man.jpg
    :width: 500px
    :alt: UART COM Port

UART5 Terminal Setup
------------------------

* Open a new terminal window. This guide will be using TeraTerm but other emulators like PuTTY will work as well.

 .. image:: ../../images/phycore-am57x/pb-057948_uart-new-terminal.jpg
    :width: 500px
    :alt: Open a New Terminal Session

* Set the serial parameters: 115200 Baud, 8 bit data, no parity bits, 1 stop bit and no flow control.

.. image:: ../../images/phycore-am57x/pb-057948_uart-serialconfig.jpg
    :width: 500px
    :alt: Setup Serial Port

.. image:: ../../images/phycore-am57x/pb-057948_uart-terminal-settings.jpg
    :width: 350px
    :alt: Terminal Settings

* Select a COM port that coresponds to the one USB to RS-232 serial adapter port.


UART5 Setting the Baud Rate
------------------------------

* In the terminal window connected to X18 UART3, the development kit default serial port, enter the following to set the communication rate for UART5:

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

        stty -F /dev/ttyS4 115200

Sending a Message to UART5
---------------------------

* Now try sending a message to UART5 terminal (X17). In the X18 terminal, enter the following command:

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

        echo You did it! > /dev/ttyS4

* Take a look at the UART5 terminal.

  .. code-block:: none
    :caption: Expected Output (UART5 console)

    You did it!

  .. note::
        If you have trouble receiving or sending messages to a Console Terminal, ensure that you have the correct COM port set and the terminal is configured for 8 bit data, no parity bits, 1 stop bit, and a baud rate of 115200.

Receiving a Message from UART5
---------------------------------

* To receive messages from your host machine, set your Linux console to output any incoming data from the UART5 connection:

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

        cat /dev/ttyS4

* Now send a message from the UART5 console to the Linux console. Type anything you want and then hit the "Enter" button.

* Enter Ctrl + C in the Linux console to stop waiting for incoming data.