.. _rs232-485_s:

RS232/485 Half Duplex
=====================

Description
-----------

This feature, present ton :ref:`OI-Core<OI-Core>`/:ref:`OI-CoreLite<OI-CoreLite>` allow you to use two different protocol on same physical interface: RS485 half duplex or RS232.

There is no terminaison resistance. If you use RS485 bus and place the module at end of line you will need to add a 120Ohms resistance.

Characteristics
---------------

.. list-table:: RS232 specifications
   :widths: 33 33 33
   :header-rows: 1

   * - Requirements
     - Type
     - Value
   * - Driver output voltage (min)
     - ±5V
     - loaded with 3kΩ to Ground
   * - Receiver input voltage high
     - 2.2V 
     - above this value, a logic '1' is guaranteed
   * - Receiver input voltage low
     - 0.8V 
     - below this value, a logic '0 ' is guaranteed
   * - Receiver maximum input voltage
     - 25V 
     -
   * - Receiver minimum input voltage
     - -25V 
     - 

.. list-table:: RS485 specifications
   :widths: 33 33 33
   :header-rows: 1

   * - Requirements
     - Type
     - Value
   * - Driver differential voltage (typical)
     - 2V
     -
   * - Driver differential voltage (min)
     - 1.5V
     -
   * - Driver differential voltage (max)
     - 5V
     -
   * -
     -
     -
   * -
     -
     - 


Code examples
-------------

The example code above demonstrates how to use RS232 on :ref:`OI-Core<OI-Core>`/:ref:`OI-CoreLite<OI-CoreLite>`.

.. literalinclude:: ../../oi-firmware/examples/RS232.cpp
    :language: cpp

The example code above demonstrates how to use RS485 on :ref:`OI-Core<OI-Core>`/:ref:`OI-CoreLite<OI-CoreLite>`.

.. literalinclude:: ../../oi-firmware/examples/RS485.cpp
    :language: cpp



Software API
------------

.. doxygenclass:: RS
   :members: