A microcontroller system includes a processing unit supporting at least one near or sub Vt circuit and a plurality of memory blocks, each memory block connected to a DMA controller and independently power controlled. A power control system uses power gates to power control at least the memory blocks. In some embodiments, a wake-up interrupt controller is connected to the power control system and a voltage regulator system is used to supply voltage to separate power domains, with the voltage regulator systems controlled at least in part by power gates operated by the power control system. A plurality of clocks can be connected to define clock domains associated with separate power domains.