I am currently making a 6 voice polyphonic synthesizer. I recently posted on this forum and your advice was very valuable.

The signals of the switch and potentiometers of the controller are converted into a midi message by a teensy. These midi messages are transmitted to 6 voices by USB. Each voice is composed of a teensy, they receive MIDI messages from the controller via USB to drive DACs and digipots.

I finish the diagram of the controller midi, but being novice I would like to have your opinions and / or your advice.

The teensy has a lot of work. I explain how it should work.

The switches and potentiometers are managed by MUX4067, each is connected to Teensy on analog pins.

The keyboard is a Fatar 37 keys with velocity. It is a 10x8 matrix keyboard. The keyboard columns are connected to the PORTC pins of the Teensy, the lines to the PORTD. This should allow for a high sampling frequency.

A 16x8 LED matrix screen is managed by I2C (slc1 / sda1) and a sequencer (Trellis) by I2C (slc0 / sda0)

For the controller to be "visual" there are many LEDs connected to a TLC5940 chain to manage them individually.

To finish the midi messages are transmitted to the voices via a USB hub 7 ports managed by usb2517.

On the right side of the diagram there are several outputs and inputs that are on other PCBs. The whole diagram concerns a single PCB, that of the front panel. I put some pictures to give you an idea.

Very cordially