.. _esb_ptx:

Enhanced ShockBurst: Transmitter
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.. contents::
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The Enhanced ShockBurst Transmitter sample shows the basic steps that are needed to transmit and receive packets using :ref:`ug_esb`.

Requirements
************

The sample supports the following development kits:

.. table-from-sample-yaml::

Additionally, if you want to test the Enhanced ShockBurst Receiver functionality, you need to build and run the :ref:`esb_prx` sample.
You can use any two of the development kits listed above and mix different development kits.

Overview
********

The sample consists of a Transmitter that uses the :ref:`esb_README` library.
After building and programming each sample on an nRF52 Series development kit, you can test that packets that are sent by the kit that runs the Transmitter sample are picked up by the kit that runs the :ref:`Receiver <esb_prx>` sample.
Successful communication is indicated by LED changes, which should be in sync on both kits.

The Transmitter sends a packet, waits for a configurable time (50 milliseconds by default), and then sends another packet.
The LEDs indicate that packets were sent and acknowledged.
Therefore, if packets are successfully received and acknowledged by the Receiver, the LED pattern changes every 50 milliseconds (with the default delay).

User interface
***************

LED 1-4:
   Indicate that packets are sent or received.
   The first four packets turn on LED 1, 2, 3, and 4.
   The next four packets turn them off again in the same order.

Configuration
*************

|config|

Building and running
********************

The Transmitter sample can be found under :file:`samples/esb/esb_ptx` in the |NCS| folder structure.

See :ref:`building` and :ref:`programming` for information about how to build and program the application, respectively.

FEM support
===========

.. include:: /includes/sample_fem_support.txt

Testing
=======

After programming the Transmitter sample on one of the development kits and the Receiver sample on the other kit, you can test their functionality.

Complete the following steps to test both the Transmitter and Receiver samples:

1. Power on both kits.
#. Observe that the LEDs change synchronously on both kits.
#. Optionally, connect to the kits with a terminal emulator (for example, nRF Connect Serial Terminal).
   See :ref:`test_and_optimize` for the required settings and steps.
#. Observe the logging output for both kits.

Dependencies
************

This sample uses the following |NCS| library:

* :ref:`esb_readme`

In addition, it uses the following Zephyr libraries:

* :file:`include/zephyr/types.h`
* :ref:`zephyr:logging_api`
* :ref:`zephyr:kernel_api`:

  * :file:`include/kernel.h`
  * :file:`include/irq.h`

* :ref:`zephyr:api_peripherals`:

   * :file:`include/gpio.h`