With this and previous patches the stm32 port can now be compiled using
object representation D (nan boxing). Note that native code and frozen mpy
files with float constants are currently not supported with this object
representation.
Printing debugging info by defining MICROPY_DEBUG_VERBOSE expects
a definition of the DEBUG_printf function which is readily available
in printf.c so include that file in the build. Before this patch
one would have to manually provide such definition which is tedious.
For the msvc port disable MICROPY_USE_INTERNAL_PRINTF though: the
linker provides no (easy) way to replace printf with the custom
version as defined in printf.c.
Prior to this patch there was a large latency for executing scheduled
callbacks when when Python code is sleeping: at the heart of the
implementation of sleep_ms() is a call to vTaskDelay(1), which always
sleeps for one 100Hz tick, before performing another call to
MICROPY_EVENT_POLL_HOOK.
This patch fixes this issue by using FreeRTOS Task Notifications to signal
the main thread that a new callback is pending.
This patch allows scripts to have more control over the software WDT. If
an instance of machine.WDT is created then the underlying OS is prevented
from feeding the software WDT, and it is up to the user script to feed it
instead via WDT.feed(). The timeout for this WDT is currently fixed and
will be between 1.6 and 3.2 seconds.
A flash erase/write takes a while and during that time tasks may be
scheduled via an IRQ. To prevent overflow of the task queue (and loss of
tasks) call ets_loop_iter() before and after slow flash operations.
Note: if a task is posted to a full queue while a flash operation is in
progress then this leads to a fault when trying to print out the error
message that the queue is full. This patch doesn't try to fix this
particular issue, it just prevents it from happening in the first place.
