The python and C modules that are supposed to be built into the firmware
image (i.e. those that are in manifest.py or in USER_C_MODULES) have
been moved to the software/modules directory.
The software/src directory should now only contain python scripts and
other files that should be installed to the Picos flash filesystem. The
idea is that these should be those scripts that implement the
application behaviour, as these are the ones that a user who does not
want to build the whole firmware themself wants to modify.
Rename the exising audiocore C module to _audiocore and create a new
Micropython wrapper module audiocore. This makes it easier to implement
async methods.
Add interrupt support to _audiocore that notifies core0 whenever data
has been consumed from the MP3 bitstream buffer.
Use this interrupt and an asyncio.ThreadSafeFlag to implement
audiocore.async_put which will play back the provided buffer, allowing
other async tasks to run while waiting for space in the bitstream
buffer.
The builtin micropython SD card driver using the default micropython SPI
implementation suffered from very low read speeds. Add an optimized SD
card driver using rp2 PIO and DMA. Currently read only, write support to
be added later.
Signed-off-by: Matthias Blankertz <matthias@blankertz.org>
