OpenFPGA/docs/source/manual/file_formats/io_mapping_file.rst

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.. _file_format_io_mapping_file:
I/O Mapping File (.xml)
-----------------------
The I/O mapping file aims to show
- What nets have been mapped to each I/O
- What is the directionality of each mapped I/O
An example of design constraints is shown as follows.
.. code-block:: xml
<io_mapping>
<io name="gfpga_pad_GPIO_PAD[6:6]" net="a" dir="input"/>
<io name="gfpga_pad_GPIO_PAD[1:1]" net="b" dir="input"/>
<io name="gfpga_pad_GPIO_PAD[9:9]" net="out_c" dir="output"/>
</io_mapping>
.. option:: name="<string>"
The pin name of the FPGA fabric which has been mapped, which should be a valid pin defined in OpenFPGA architecture description.
.. note:: You should be find the exact pin in the top-level module of FPGA fabric if you output the Verilog netlists.
.. option:: net="<string>"
The net name which is actually mapped to a pin, which should be consistent with net definition in your ``.blif`` file.
.. option:: dir="<string>"
The direction of an I/O, which can be either ``input`` or ``output``.