After a break of several weeks I am now back to my Polysnth Project. I decided to use one Controller with graphic display for the panel, keyboard and MIDI stuff and one controller for generating then CVs LFOs an Envelopes. Here the first picture of one pot multiplexer board.
I use the STM32F746 discovery board with the great library from UB
The control signals for the Multiplexers are generated with an MCP23S17. for converting the pot values i use the internal ADC of the µC in 8 bit mode.
When a value is changed the new value is send via I2C to the voice µC.