Aspects of the disclosure are directed to a system having a particularly-configured microcontroller. In one embodiment, the microcontroller includes the following: a processor; a processor data bus connected to the processor; a set of peripherals; a peripheral data bus connected to the peripherals; a peripheral bus bridge providing an interface between the processor data bus and the peripheral data base and including a plurality of special function register bank blocks that are internal to the microcontroller, each register bank block having a respective output; and a register bank block decoder circuit for decoding interrupts to provide a selection output for activation of one of the plurality of register bank blocks.