Changes here make the zephyr port act the same as other ports for the
start up and shut down sequence:
- `boot.py` is executed if it exists, and can force a soft reset
- `main.py` is only executed if in friendly REPL and if `boot.py` executed
  successfully; and it can also force a soft reset
- print "MPY: " before "soft reboot" on soft reset

Signed-off-by: Damien George <damien@micropython.org>

If there is a filesystem available, this change makes sure there is a "lib"
in `sys.path`, eg so that "mip install" works correctly.

Signed-off-by: Damien George <damien@micropython.org>

This change enables `sys.stdin`, `sys.stdout` and `sys.stderr` objects.
They are useful for general IO, and also help with testing zephyr boards.

Signed-off-by: Damien George <damien@micropython.org>

There are two changes here:

1. Increase the UART input bufffer to 512 bytes.  That's necessary to get
   basic REPL reliability tests working, and helps improve `mpremote`
   usage, eg copying large files.

2. Remove `uart_sem` semaphore.  This is no longer needed because
   `zephyr_getchar()` should be fully non-blocking and have as low a
   latency as possible.  `mp_hal_stdin_rx_chr()` (which calls
   `zephyr_getchar`) already uses `MICROPY_EVENT_POLL_HOOK` to get
   an efficient wait, and doing an extra wait and check for the
   semaphore in `zephyr_getchar()` just introduces unnecessary latency and
   can lead to slower input, and potentially overflowing the UART input
   buffer.

Signed-off-by: Damien George <damien@micropython.org>

The blocklist argument is not available in zephyr 4.0.0.

Signed-off-by: Damien George <damien@micropython.org>

Adding this constant is all that's needed to support open-drain pins.

Signed-off-by: Damien George <damien@micropython.org>

Following other ports.

Signed-off-by: Damien George <damien@micropython.org>

Signed-off-by: Damien George <damien@micropython.org>

These work now that the C-level pin HAL is implemented.

Signed-off-by: Damien George <damien@micropython.org>

Support for importing .mpy files is quite fundamental to MicroPython these
days, eg it allows installing more efficient .mpy code via "mip install"
(and installing `unittest` only works with the .mpy version because the .py
version uses f-strings, which are not enabled on the zephyr port).  So
enable it generally for use by all boards.

As part of this, also enable:
- min/max: needed by `micropython/import_mpy_invalid.py`, and widely used
- sys.modules: needed by `run-tests.py` to run .mpy tests with --via-mpy
- io module: needed to run .mpy tests, and useful for `io.IOBase`
- array slice assign: needed to run .mpy tests, and generally useful as a
  way to do a memory copy.

Signed-off-by: Damien George <damien@micropython.org>

Needed for some ARMv6M boards, eg rpi_pico.

Signed-off-by: Damien George <damien@micropython.org>

Changes:
- Enable CONFIG_PWM so that `machine.PWM()` works.
- Increase MicroPython GC heap size.

Signed-off-by: Damien George <damien@micropython.org>

Bluetooth works well now on this board, so enable all supported features.

Also increase the MicroPython GC heap size to make use of the available
RAM.

Unfortunately the filesystem does not match the stm32 port's NUCLEO_WB55
configuration.  That's not possible to do because stm32 uses a 512 byte
flash erase size, while zephyr uses 4096 bytes.  But at least here in
zephyr there's now a sizable and usable filesystem.

Signed-off-by: Damien George <damien@micropython.org>

Although the rpi_pico can already build and run with the zephyr port, this
configuration improves it in a number of ways:
- Use the USB CDC ACM as the REPL, rather than just a UART.
- Enable I2C and SPI, and add I2C1.
- Enable a filesystem, which matches exactly the rp2 port's RPI_PICO
  configuration.  So switching between zephyr and rp2 is possible and will
  retain the filesystem.
- Make the MicroPython GC heap make the most use of the available RAM.

Signed-off-by: Damien George <damien@micropython.org>

Costs +48 bytes.  Useful to introspect the target.

Signed-off-by: Damien George <damien@micropython.org>

Needed to pass exception tests.

Signed-off-by: Damien George <damien@micropython.org>

With a default of -1, for soft timer.  This matches other ports, and the
`extmod/machine_timer.c` implementation.

This change allows the `tests/extmod/machine_soft_timer.py` test to pass.

Signed-off-by: Damien George <damien@micropython.org>

Some targets like frdm_k64f don't support GPIO_OUTPUT|GPIO_INPUT, so just
use GPIO_OUTPUT in those cases (it seems they still support reading the
current output state even when configured only as GPIO_OUTPUT, unlike other
targets which require both settings).

Signed-off-by: Damien George <damien@micropython.org>