45eec5b5a5
I recently misdiagnosed a "maybe-uninitialized" diagnostic as a bug in asf4. However, the problem was in our SPI code. A special case for samr21 MCUs was being applied to same54p20a and possibly other D5x/E5x MCUs, since the check was simply for pin PC19 existing at all. Change the check to use the macro PIN_PC19F_SERCOM4_PAD0 which is only defined if special function F of pin PC19 is SERCOM4 PAD0. Reorganize the code a little bit so that brace-matching in editors is not confused by the conditionalized code, including an unrelated change for APA102_SCK's condition. Revert the change to the Makefile that incorrectly attempted to silence the diagnostic.
SAMD21 and SAMD51
==================
This port supports many development boards that utilize SAMD21 and SAMD51 chips. See
https://circuitpython.org/downloads for all supported boards.
Building
--------
For build instructions see this guide: https://learn.adafruit.com/building-circuitpython/
Debugging
---------
For debugging instructions see this guide: https://learn.adafruit.com/debugging-the-samd21-with-gdb
Port Specific modules
---------------------
.. toctree::
../../shared-bindings/samd/index