There were several problems with the way this worked -- the read_count
approach was too complicated and I made a mistake "simplifying" it from
WaveFile. And when the right channel was returned, it was off by 1 byte,
making it into static.
Instead, directly track which is the "other" channel that has data
available, and by using the right data type make the "+ channel"
arithmetic give the right result.
This requires a double cast (int16_t*)(void*) due to an alignment warning;
the alignment is now ensured manually, but the compiler doesn't make the
necessary inference that the low address bit must be clear.
When a playing mp3 is deinitted, it's possible to reach get_buffer,
but all the internal pointers are NULL. This would lead to a hard fault.
Avoid it by returning GET_BUFFER_ERROR instead.
We weren't correctly collecting the start and stop sequences. As
a result, the GC would free the space and allocate other info
there.
Thanks to JacobT on Discord for the bug report!
This code is shared by most parts, except where not all the #ifdefs
inside the tick function were present in all ports. This mostly would
have broken gamepad tick support on non-samd ports.
The "ms32" and "ms64" variants of the tick functions are introduced
because there is no 64-bit atomic read. Disabling interrupts avoids
a low probability bug where milliseconds could be off by ~49.5 days
once every ~49.5 days (2^32 ms).
Avoiding disabling interrupts when only the low 32 bits are needed is a minor
optimization.
Testing performed: on metro m4 express, USB still works and
time.monotonic_ns() still counts up
This PR refines the _bleio API. It was originally motivated by
the addition of a new CircuitPython service that enables reading
and modifying files on the device. Moving the BLE lifecycle outside
of the VM motivated a number of changes to remove heap allocations
in some APIs.
It also motivated unifying connection initiation to the Adapter class
rather than the Central and Peripheral classes which have been removed.
Adapter now handles the GAP portion of BLE including advertising, which
has moved but is largely unchanged, and scanning, which has been enhanced
to return an iterator of filtered results.
Once a connection is created (either by us (aka Central) or a remote
device (aka Peripheral)) it is represented by a new Connection class.
This class knows the current connection state and can discover and
instantiate remote Services along with their Characteristics and
Descriptors.
Relates to #586
While finding sources of clicks and buzzes in nrf i2sout, I identified
this site as one which could be long running. Reproducer code was to
play a 22.05kHz sample and repeatedly print `os.listdir('')`
These arguments are constrained to be compile-time constants, a fact
that gcc complains about under "-Og" optimization, but not in normal
builds. Declare them as enumerated types
Also, move the rendering setup code to shared-module from
shared-bindings.
In CP 5.0, displayio_display_core_set_region_to_update now starts
its own transaction, so it has to be moved outside of the transaction
started by the render call.
