There is no need to put these in the board files as the I2S is the same
on all Microchip SAM D21 chips. This simplifies the code and avoids some
special *_baremetal.go files.
This change does not change the resulting binaries.
This has practically no effect on the resulting binaries, the only
difference I could find was for the flash/console/spi driver example.
I'm not sure how to test that one, but I think it's very unlikely that
code will have changed in any meaningful way (apart from reordering some
globals).
This commit changes the I2C declarations so that the objects are
instantiated in each chip file (e.g. machine_atsamd21e18.go) and used to
define I2C0 (and similar) in the board file (e.g. board_qtpy.go). This
should make it easier to define new board files, and reduces the need
for separate *_baremetal.go files.
I have tested this the following way:
- With the LIS3DH driver example on the Circuit Playground Express and
the PyBadge.
- With the LSM6DS3 driver example on the Arduino Nano 33 IoT.
They both still work fine.
Instead of defining them separately for each board, define them once in
the chip definition and later simply use &sercomUART1 etc. to refer to
them. This is simpler and less error-prone.
I found two bugs while working on this:
- The P1AM-100 board mixed SERCOM 5 and SERCOM 3. It looks like SERCOM
5 was intended, based on the used pins.
- The Adafruit Matrix Portal appears to have configured the wrong
interrupt.
Unfortunately, I can't test these fixes. However, they make it clear
that such a change is important to avoid bugs.
I tested this commit on the PyBadge and the Circuit Playground Express.
