xref: /aosp_15_r20/external/pigweed/pw_stream_uart_linux/docs.rst (revision 61c4878ac05f98d0ceed94b57d316916de578985)

.. _module-pw_stream_uart_linux:

====================
pw_stream_uart_linux
====================
``pw_stream_uart_linux`` implements the
:cpp:class:`pw::stream::NonSeekableReaderWriter` interface for reading from and
writing to a UART using Linux TTY interfaces.

.. note::
  This module will likely be superseded by a future ``pw_uart`` interface.

C++
===
.. doxygenclass:: pw::stream::UartStreamLinux
   :members:

Examples
========
A simple example illustrating only changing baud-rate and writing to a UART:

.. code-block:: cpp

   constexpr const char* kUartPath = "/dev/ttyS0";
   constexpr pw::stream::UartStreamLinux::Config kConfig = {
     .baud_rate = 115200,
    // Flow control is unmodified on tty.
   };
   pw::stream::UartStreamLinux stream;
   PW_TRY(stream.Open(kUartPath, kConfig));

   std::array<std::byte, 10> to_write = {};
   PW_TRY(stream.Write(to_write));


A simple example illustrating enabling flow control and writing to a UART:

.. code-block:: cpp

   constexpr const char* kUartPath = "/dev/ttyS0";
   constexpr pw::stream::UartStreamLinux::Config kConfig = {
     .baud_rate = 115200,
     .flow_control = true, // Enable hardware flow control.
   };
   pw::stream::UartStreamLinux stream;
   PW_TRY(stream.Open(kUartPath, kConfig));

   std::array<std::byte, 10> to_write = {};
   PW_TRY(stream.Write(to_write));

Caveats
=======
No interfaces are supplied for configuring data bits, stop bits, or parity.
These attributes are left as they are already configured on the TTY; only the
speed or flow control is modified.