Tiny $29 computer lets you build DIY synths, pedals, and more
theverge.com
theverge.com
Some years ago I did a similar board hooking an STM32F4 to a TLV320AIC3256 CODEC. TI provides an audio development IDE, PurePath [0], to program the embedded miniDSP where you can 'code' and configure different effects graphically (they even have a guitar FX demo, tool written in LabVIEW - yikes!).
Sadly they don't disclose the low level programming instruction codes, therefore changing things programmatically in the microcontroller at runtime is limited. I tried to reverse engineer the instructions with limited success, and then I just lost interest. ¯\_(ツ)_/¯
The advantage of having a cheap tiny board is that you can build a system like a polyphonic synth with very capable voices with relative ease. And since each one has inputs too, you can interconnect signals giving a lot of flexibility (aka modular synth).