i have a code written for atmel atmega2560. currently it is used on that MCU. now i am upgrading the MCU to 32 bit, So that i could establish communication via usb protocol. Because in the whole system the speed is very low. now can i use the same code written for atmega2560 to run on 32 bit MCU's with some necessary adjustments regarding USB protocol. The MCU is not yet decided.I cannot figure out which MCU might be best suited for this kind of job.No extra job is added, just USB protocol will be implemented. I am a bit inclined towards stm32 series but i donot have have an idea, how much code variation will be there. Also AVR32UC3 family is an option because atmel atmega2560 is AVR and AVR32UC3 is also AVR. also ethernet protocol will b implemented afterwards.