Add notes to docs indicating SoftCore bringup with VCU118 is legacy

This commit is contained in:
Jerry Zhao
2023-04-20 00:00:42 -07:00
parent 4f5bbdca97
commit d42b195b91
2 changed files with 15 additions and 5 deletions

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@@ -206,8 +206,12 @@ This type of simulation setup is done in the following multi-clock configuration
:start-after: DOC include start: MulticlockAXIOverSerialConfig
:end-before: DOC include end: MulticlockAXIOverSerialConfig
Bringup Setup of the Example Test Chip after Tapeout
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Softcore-driven Bringup Setup of the Example Test Chip after Tapeout
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. warning::
Bringing up test chips with a FPGA softcore as described here is discouraged.
An alternative approach using the FPGA to "bridge" between a x86 host and the test chip is the preferred approach.
Assuming this example test chip is taped out and now ready to be tested, we can communicate with the chip using this serial-link.
For example, a common test setup used at Berkeley to evaluate Chipyard-based test-chips includes an FPGA running a RISC-V soft-core that is able to speak to the DUT (over an FMC).
@@ -222,4 +226,4 @@ The following image shows this flow:
.. image:: ../_static/images/chip-bringup.png
In fact, this exact type of bringup setup is what the following section discusses:
:ref:`Prototyping/VCU118:Introduction to the Bringup Design`.
:ref:_legacy-vcu118-bringup.

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@@ -47,8 +47,14 @@ After the harness is created, the ``BundleBridgeSource``'s must be connected to
This is done with harness binders and io binders (see ``fpga/src/main/scala/vcu118/HarnessBinders.scala`` and ``fpga/src/main/scala/vcu118/IOBinders.scala``).
For more information on harness binders and io binders, refer to :ref:`Customization/IOBinders:IOBinders and HarnessBinders`.
Introduction to the Bringup Design
----------------------------------
(Legacy) Introduction to the Legacy Bringup Design
--------------------------------------------------
.. warning::
The bringup VCU118 design described here is designed for old versions of Chipyard SoCs, pre-1.9.1.
The key difference is that these designs rely on a clock generated on-chip to synchronize the slow serialized-TileLink interface.
After Chipyard 1.9.1, the FPGA host is expected to pass the clock to the chip, instead of the other way around.
A new bringup solution will be developed for post-1.9.1 Chipyard designs.
An example of a more complicated design used for Chipyard test chips can be viewed in ``fpga/src/main/scala/vcu118/bringup/``.
This example extends the default test harness and creates new ``Overlays`` to connect to a DUT (connected to the FMC port).