2023-10-23 19:21:37 +02:00
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====================================
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2023-10-21 12:24:43 +02:00
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``usbserial`` USB Serial Hello World
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====================================
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Target configuration
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--------------------
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This is another implementation of "Hello, World" but this one uses a USB serial
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driver. Configuration options can be used to simply the test. These options
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include:
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- ``CONFIG_EXAMPLES_USBSERIAL_INONLY`` – Only verify IN (device-to-host) data
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transfers. Default: both.
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- ``CONFIG_EXAMPLES_USBSERIAL_OUTONLY`` – Only verify OUT (host-to-device) data
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transfers. Default: both.
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- ``CONFIG_EXAMPLES_USBSERIAL_ONLYSMALL`` – Send only small, single packet
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messages. Default: Send large and small.
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- ``CONFIG_EXAMPLES_USBSERIAL_ONLYBIG`` – Send only large, multi-packet messages.
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Default: Send large and small.
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If ``CONFIG_USBDEV_TRACE`` is enabled (or ``CONFIG_DEBUG_FEATURES`` and
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``CONFIG_DEBUG_USB``), then the example code will also manage the USB trace
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output. The amount of trace output can be controlled using:
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- ``CONFIG_EXAMPLES_USBSERIAL_TRACEINIT`` – Show initialization events.
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- ``CONFIG_EXAMPLES_USBSERIAL_TRACECLASS`` – Show class driver events.
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- ``CONFIG_EXAMPLES_USBSERIAL_TRACETRANSFERS`` – Show data transfer events.
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- ``CONFIG_EXAMPLES_USBSERIAL_TRACECONTROLLER`` – Show controller events.
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- ``CONFIG_EXAMPLES_USBSERIAL_TRACEINTERRUPTS`` – Show interrupt-related events.
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Error results are always shown in the trace output.
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Host-side test program
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----------------------
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In additional to the target device-side example, there is also a host-side
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application in this directory. This host side application must be executed on a
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Linux host in order to perform the ``USBSERIAL`` test. The host application can be
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compiled under Linux (or Cygwin?) as follows::
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cd examples/usbserial
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make -f Makefile.host TOPDIR=<nuttx-directory>
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Running the test
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----------------
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This will generate a small program called ``host``. Usage:
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1. Build the ``examples/usbserial`` target program and start the target.
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2. Wait a bit, then do enter::
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dmesg
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At the end of the dmesg output, you should see the serial device was
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successfully idenfied and assigned to a tty device, probably ``/dev/ttyUSB0``
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or ``/dev/ttyACM0`` (depending on the configured USB serial driver).
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3. Then start the host application::
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./host [<tty-dev>]
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Where:
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- ``<tty-dev>`` is the USB TTY device to use. The default is ``/dev/ttyUSB0``
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(for the PL2303 emulation) or ``/dev/ttyACM0`` (for the CDC/ACM serial
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device).
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The host and target will exchange are variety of very small and very large
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serial messages.
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