.. _gowin:

Gowin notes
###########

GOWIN GW1N
==========

.. NOTE::

  * Trenz TEC0117
  * Sipeed Tang Nano
  * Sipeed Tang Nano 4K
  * Honeycomb
  * RUNBER

``.fs`` file is the default format generated by *Gowin IDE*, so nothing special must be done to generates this file.

Since the same file is used for SRAM and Flash a CLI argument is used to specify the destination.

Flash SRAM
----------

with ``-m``:

.. code-block:: bash

    openFPGALoader -m -b BOARD_NAME impl/pnr/*.fs

where ``BOARD_NAME`` is:

* ``tec0117``
* ``tangnano``
* ``tangnano4k``
* ``tangnano9k``
* ``runber``

Flash
-----

.. ATTENTION::
  Only with Trenz TEC0117 and runber.

with ``-f``, file load:

.. code-block:: bash

    openFPGALoader -f -b BOARD_NAME impl/pnr/*.fs

where ``BOARD_NAME`` is:

* ``tec0117``
* ``runber``

It's possible to flash external SPI Flash (connected to MSPI) in bscan mode by using ``--external-flash`` instead of
``-f``.

.. NOTE::

  Gowin's FPGA may fails to be detected if **JTAGSEL_N** (pin 08 for *GW1N-4K*) is used as a GPIO.
  To recover you have to pull down this pin (before power up) to recover JTAG interface (*UG292 - JTAGSELL_N section*).
