CircuitPython - a Python implementation for teaching coding with microcontrollers https://git.suspectdevices.com/suspect-devices/circuitpython/atom?h=encoding 2020-01-16T16:48:38+00:00 2020-01-16T16:48:38+00:00 Jeff Epler jepler@gmail.com 2020-01-12T17:02:47+00:00 urn:sha1:449dbea4567dbc27a01ae695b9cebf776a6927f0 This removes downscaling (halving-add) when multiple voices are being mixed. To avoid clipping, and get similar behavior to before, set the "level" of each voice to (1/voice_count). Slow paths that were applicable to only M0 chips were removed. As a side effect, the internal volume representation is now 0 .. 0x8000 (inclusive), which additionally makes a level of exactly 0.5 representable. Testing performed, on PyGamer: For all 4 data cases, for stereo and mono, for 1 and 2 voices, play pure sign waves represented as RawSamples and view the result on a scope and through headphones. Also, scope the amount of time spent in background tasks. Code size: growth of +272 bytes Performance (time in background task when mixing 2 stereo 16-bit voices): 76us per down from 135us (once per ~2.9ms long term average) (Decrease from 4.7% to 2.4% of all CPU time) 2019-08-25T04:36:18+00:00 sommersoft sommersoft@gmail.com 2019-08-25T04:36:18+00:00 urn:sha1:df5568d993ad10bb6ef68fc0f01f8561f3a6c78d