The MPD218 in post above, outputs MiDi messages over USB , with the A B C selectors assigning various parameters
( channel , volume, attack etc ) the knobs do A/D for the MiDi control bytes. ( it could be done with a FTDI serial - USB ) the.......... DF "i need 64 analog input microcontroler that may be switched in 3 positions " suggests he/she wants 64 knobs feeding 64 AD channels turned into MiDi control messages , merged with 3 (ABC) settings.. ( frown !)