Use the machine.deepsleep() function to enter the sleep mode.  Use the
RTC to configure the alarm to wake the device.

Basic use is the following:

    import machine

    # configure RTC's ALARM0 to wake device from deep sleep
    rtc = machine.RTC()
    rtc.irq(trigger=rtc.ALARM0, wake=machine.DEEPSLEEP)

    # do other things
    # ...

    # set ALARM0's alarm to wake after 10 seconds
    rtc.alarm(rtc.ALARM0, 10000)

    # enter deep-sleep state (system is reset upon waking)
    machine.deepsleep()

To detect if the system woke from a deep sleep use:

    if machine.reset_cause() == machine.DEEPSLEEP_RESET:
        print('woke from deep sleep')

Flash size as seen by vendor SDK doesn't depend on real size, but rather on
a particular value in firmware header, as put there by flash tool. That means
it's user responsibility to know what flash size a particular device has, and
specify correct parameters during flashing. That's not end user friendly
however, so we try to make it "flash and play" by detecting real size vs
from-header size mismatch, and correct the header accordingly.

There's no space for it.

Returns FlashROM size in bytes from vendor SDK's point of view, not
physical size.

Should be called to notify that current dupterm object has more input
data to read.

"" is the correct name of the root directory when mounting a device there
(as opposed to "/").  One can now do os.listdir('/') and open('/abc'), as
well as os.listdir() and open('abc').

These are *defined* per-port, but why redeclare them again and again.

A shortcut for users to provide background diagnostic info for bug
reports.

esponewire.c contains low-level timing-critical functions that go in
iRAM.  modonewire.c contains Python wrapper code.

Now pins can be easily looked up in the table using the pin number as the
index and vice versa.

This field is the same as phys_port and not needed.

The config variable MICROPY_MODULE_FROZEN is now made of two separate
parts: MICROPY_MODULE_FROZEN_STR and MICROPY_MODULE_FROZEN_MPY.  This
allows to have none, either or both of frozen strings and frozen mpy
files (aka frozen bytecode).

First deactivate, then print diagnostic message.

The idea is that if dupterm object can handle exceptions, it will handle
them itself. Otherwise, object state can be compromised and it's better
to terminate dupterm session. For example, disconnected socket will keep
throwing exceptions and dump messages about that.

By default it uses mp_plat_print, but a port may override it to another
value with MICROPY_DEBUG_PRINTER_DEST.

nlr_pop must be called if no exception was raised.

Also, return value of these callback helpers is made void because ther
is (currently) no use for it.

Also include py/obj.h so the header is self contained.

Main entry point is _boot.py which checks whether FAT FS in flash mountable,
and if so, mounts it. Otherwise, it checks if flash is empty, and if so,
performs initial module setup: makes FAT FS, configures default AP name,
etc. As a last option, if flash is not empty, and could not be mounted,
it means filesystem corruption, and warning message with instructions is
printed in an infinite loop.