Juno6pm Input Board: The hardware

The Juno6pm input board is the board that will handle MIDI input (to solve the CPU hogging issue caused by Raspberry Pi USB MIDI), the knobs and the switches. It will be connected to the Raspberry Pi through serial. The board I am planning on using is the AVR synth that I bought a while ago from elby-designs:

Since this whole project is a virtual analog synth, I decided that I will not be using my AVR Synth anymore and I better give it a better use (also I have little time do design a new board, build the pcb, solder components, etcetera).
The idea is to keep the 8 potentiometers, replace the 16 switches with momentary pushbuttons and remove the dac completely.
As for the software that will run in the AVR, it will receive MIDI from standard 5 Pin MIDI connector using the hardware UART and send it to the Raspberry Pi, toghether with potentiomer and switches values, by bit banging serial.
Once I am done with the whole project I might think of making a new board just for this project, but till then this will be my juno6pm input board.