* atmel-samd: Remove ASF3. This will break builds.
* atmel-samd: Add ASF4 for the SAMD21 and SAMD51.
* Introduce the supervisor concept to facilitate porting.
The supervisor is the code which runs individual MicroPython VMs. By
splitting it out we make it more consistent and easier to find.
This also adds very basic SAMD21 and SAMD51 support using the
supervisor. Only the REPL currently works.
This begins the work for #178.
* atmel-samd: Introduce a nvm module for non-volatile byte-level memory access.
This allows for persisting small configuration values even when the file system
is read-only from CircuitPython.
Fixes#160
* Review feedback:
* Add tests.
* Fix non-zero index.
* Fix len()
Reworked frozen module support: clean up makefiles and handle multiple directories.
Modules to freeze are included as git submodules.
Add neopixel to circuitplayground express build.
Fixes#56
* Reset SWD lines to SWD rather than GPIO. This makes OpenOCD happier.
* Default speaker enable lines to False for CircuitPlayground to prevent
the speaker from buzzing when no sound is playing. Fixes#126
Also replace use of PINMUX_DEFAULT with PINMUX_UNUSED to prevent any
accidental pin changes. This caused user SPI to break internal SPI
flash on the Feather M0 Express.
Fixes#100
* Track status pin use by user code separately so it can take over the pins and then give them back.
* Switch to hardware SPI for APA102 on Gemma and Trinket.
* Merge microcontroller/types.h into microcontroller/Pin.h to better match approach going forwards.
* Always init SPI to 250k to start for SD cards.
* Add ability to configure byte written during read.
* Add ability to read and write to portions of buffers like existing I2C API.
You can either set it once up front, or set variable_frequency on custruction to
indicate that the frequency must be able to change. This informs whether a timer
can be shared amongst pins.
This also adds persistent clock calibration on atmel-samd. Once the device has
synced its clock frequency over USB it will remember that config value until USB
is used again. This helps ensure the clock frequency is similar on and off USB.
Lastly, this also corrects time.sleep() when on USB by correcting the tick counter.
