Low-power, high-performance CMOS 8-bit microcontroller with 4KB of ISP flash memory. The device uses Microchip high-density nonvolatile memory technology and is compatible with the industry-standard MCS??51 instruction set. An enhanced CPU core can fetch a single byte from memory every clock cycle and is capable of 20MIPS throughput. The new CPU core runs at a much lower speed, greatly reducing power consumption.