audiomixer module for ESP32S2

[rsbohn]

I can play WaveFiles over I2SOut but I want to control the volume and interleave samples. The audiomixer module would allow both.

[tannewt]

I believe this was disabled for ESP32-S2 because the implementation used ARM assembly. We now have a C implementation as well. I'd suggest trying to enable it yourself in a build. It may just work.

[rsbohn]

I enabled the audiomixer module for ESP32-S2, built the .uf2 file, installed it on my feathers2, and was able to mix WaveFiles.

Here's the diff:

diff --git a/ports/esp32s2/mpconfigport.mk b/ports/esp32s2/mpconfigport.mk
index 1f5021bc1..479725211 100644
--- a/ports/esp32s2/mpconfigport.mk
+++ b/ports/esp32s2/mpconfigport.mk
@@ -18,6 +18,7 @@ CIRCUITPY_AUDIOBUSIO = 1
 CIRCUITPY_AUDIOBUSIO_PDMIN = 0
 CIRCUITPY_AUDIOBUSIO_I2SOUT = 1
 CIRCUITPY_AUDIOIO = 0
+CIRCUITPY_AUDIOMIXER = 1
 CIRCUITPY_CANIO = 1
 CIRCUITPY_COUNTIO = 1
 CIRCUITPY_DUALBANK = 1