1. A single chip microcontroller comprising a master core and a slave core, wherein the master core is clocked by a master system clock and the slave core is clocked by a slave system clock and wherein each core is associated with a plurality of peripheral devices to form a master microcontroller and a slave microcontroller, respectively, further comprising a communication interface between the master microcontroller and the slave microcontroller, wherein the communication interface comprises a plurality of configurable directional data registers coupled with a flow control logic which is configurable to assign a direction to each of the plurality of configurable data registers.