BlockBiquad takes kind, f0 (center frequency) & Q (sharpness)
block type arguments and calculates the actual filter coefficients
every frame.
This allows the filter characteristics f0 and Q to be changed dynamically
from LFOs & arithmetic blocks.
A new manual test demonstrates this on a host computer, playing a simple
tone that is dynamically filtered.
This class allows much more expressive sound synthesis:
* tremolo & vibrato
* arbitrary frequency
* different evelope & waveform per note
* all properties dynamically settable from Python code
this allows to test how the midi synthesizer is working, without access
to hardware. Run `micropython-coverage midi2wav.py` and it will create
`tune.wav` as an output.
.. it needs to operate on a FILE* rather than FIL depending on
the build.
Note that this is comparing output to expected, not to cpython dotenv
package. Because run-tests.py starts the CPython interpreter with the
'-S' (skip site initialization) flag, pip-installed packages are
not available for import inside a test file. Instead, the exp
file is generated manually:
```
circuitpython/tests$ python3 circuitpython/dotenv_test.py > circuitpython/dotenv_test.py.exp
```
Unfortunately, the test fails on test e15:
```diff
FAILURE /home/jepler/src/circuitpython/tests/results/circuitpython_dotenv_test.py
--- /home/jepler/src/circuitpython/tests/results/circuitpython_dotenv_test.py.exp 2022-10-04 09:48:16.307703128 -0500
+++ /home/jepler/src/circuitpython/tests/results/circuitpython_dotenv_test.py.out 2022-10-04 09:48:16.307703128 -0500
@@ -14,7 +14,7 @@
line
e13 e13value
e14 None
-e15 e15value
+e15 None
e16 #
e17 def
e18 #has a hash
```
This allows you to list and explore connected USB devices. It
only stubs out the methods to communicate to endpoints. That will
come in a follow up once TinyUSB has it. (It's in progress.)
Related to #5986
This adds I2SOut and PDMIn support via PIO.
StateMachines can now:
* read and read while writing
* transfer in 1, 2 or 4 byte increments
* init pins based on expected defaults automatically
* be stopped and restarted
* rxfifo can be cleared and rxstalls detected (good for tracking when
the reading code isn't keeping up)
Fixes#4162
