In this work we present the design and implementation on FPGAs of a 16 bit microcontroller. Since this microcontroller has academic purposes, its architecture is simple, complete and open. Furthermore, its assembler language was also designed and a translator program in Python is provided. The arithmetic/logic unit designed only include integer operations, and we aggregate a carry free multiplier to make easy some computations needed in cryptographic and coding theory applications which require binary field arithmetic. To demonstrate its functionality we choose a non trivial application, the implementation of two Authenticated Encryption schemes CCM and GCM. Our design can be used in economic range FPGAs as Spartan 3 or faster range as Virtex 5 or higher