Chip Fit
--------

**Location:**
``TestBenches / AraTestBenches / ChipFit / (several available)``

This test bench is designed to estimate whether the components in your
design will fit within a given circuit board area. Given the footprints
of the individual components, it will try to find an arrangement that
accommodates all parts. It will then report as to whether or not the elements
can fit within the given area.

Note: The Chip Fit analysis should be used only to confirm that the
selected components **will not** fit within the given area. A
completed design will require more area for signal traces and other
considerations. Consider a "no" answer definitive but a "yes"
answer to require further investigation.

Test benches are provided for these Ara module sizes: - Front H - Front
I - Rear 1x1 - Rear 1x2 - Rear 2x2

Consult the Ara MDK for details on each size.

Configure
~~~~~~~~~

First, you'll need to create a copy of one of the **Chipfit** test
benches. For instructions, refer to the section :ref:`ara_test_bench_basics`.

No additional configuration is needed to test a design against one of
the standard Ara sizes provided. However, if you would like to test for
a different size, change the ``boardHeight`` and ``boardWidth``
*Parameters* accordingly.

Metrics
~~~~~~~

Note: In the Metric names that follow, (x) and (y) are replaced by the
**boardWidth** and **boardHeight**, respectively, as defined above.

+--------------------------------+-------------------+-------------------------+
| Name                           | Value Type        | Description             |
+================================+===================+=========================+
| fits_(x)_by_(y)                | true/false        | Whether the components  |
|                                |                   | in the design will fit  |
|                                |                   | within the given space  |
+--------------------------------+-------------------+-------------------------+
| pct_occupied_(x)_by_(y)        | real number       | The percentage of the   |
|                                |                   | available space         |
|                                |                   | occupied by the given   |
|                                |                   | components.             |
+--------------------------------+-------------------+-------------------------+

Outputs
~~~~~~~

+------------------------------+---------------------------------------------------+
| Filename                     | Description                                       |
+==============================+===================================================+
| ``showChipFitResults.bat``   | Launches a visualizer for the Chip Fit results.   |
+------------------------------+---------------------------------------------------+

Chip Fit Visualizer
~~~~~~~~~~~~~~~~~~~

Running ``showChipFitResults.bat`` in the results folder will launch the
**Chip Fit Visualizer**. This utility will show the best-case packing of
the design's elements.

If any elements failed to pack into the given area, their names will be
listed under the **Failed To Place** heading at the right side of the
diagram.

.. figure:: images/11-02-chipfitvisualizer.png
   :alt: Chip Fit Visualizer

   Chip Fit Visualizer

The **Chip Fit Visualizer** has the following controls:

-  Numpad + key: zoom in
-  Numpad - key: zoom out
-  **Esc**: quit

Assumptions
~~~~~~~~~~~

This analysis assumes that each component to be placed on the
printed circuit board (PCB) has an *EDA Model* (EAGLE Schematic file)
associated with it. Information about each component's size is taken from
that model file.