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Documents how to use the txmorse application and how it can be extended to support other output devices besides the console and GPIO. Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
44 lines
1.6 KiB
ReStructuredText
44 lines
1.6 KiB
ReStructuredText
==================================
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``txmorse`` Morse code transmitter
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==================================
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This application is an example which transmits Morse code messages using the
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:doc:`Morsey library </applications/audioutils/morsey/index>`.
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You can run ``txmorse -h`` to display help information.
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Supported Devices
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-----------------
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.. note::
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This application does not currently support all possible Morse code
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transmission devices available on NuttX NuttX. Currently, only GPIO devices
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are supported.
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In order to add support for a new output device, you must submit a patch
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modifying the program to define the interface for the Morsey library for each
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type of output device. Take a look at the current application code to see
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examples for console devices and GPIO devices.
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The ``txfunc`` function is used by the ``morsey`` library to transmit a mark.
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You can implement the appropriate driver operations (i.e. ``ioctl`` calls) in
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this function. See the GPIO implementation for an example.
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The ``cleanupfunc`` function is used to cleanup the implementation. For most
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NuttX devices, this involves closing the file descriptor.
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In the ``main`` function, the path to the output device is used to identify the
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implementation to use. For instance, GPIO devices are under ``/dev/gpio<n>``, so
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device paths containing "gpio" cause the GPIO driver to be selected. If no
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player can be associated with the device, the default player is selected which
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just prints the Morse code to the console.
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Usage
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-----
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The following will output "SOS" over a GPIO device (i.e. buzzer or LED):
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.. code:: console
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nsh> txmorse "sos" /dev/gpio0
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