2022-07-28 18:15:44 -05:00
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.. _file_format_pcf_file:
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Pin Constraints File (.pcf)
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---------------------------
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.. note:: This file is in a different usage than the Pin Constraints File in XML format (see details in :ref:`file_format_pin_constraints_file`)
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2022-07-28 21:09:53 -05:00
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The PCF file is the file which **users** should craft to assign their I/O constraints
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2022-07-28 18:15:44 -05:00
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An example of the file is shown as follows.
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.. code-block:: xml
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set_io a pad_fpga_io[0]
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set_io b[0] pad_fpga_io[4]
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set_io c[1] pad_fpga_io[6]
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.. option:: set_io <net> <pin>
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Assign a net (defined as an input or output in users' HDL design) to a specific pin of an FPGA device (typically a packaged chip).
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.. note:: The net should be single-bit and match the port declaration of the top-module in users' HDL design
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.. note:: FPGA devices have different pin names, depending their naming rules. Please contact your vendor about details.
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