The S3CB018/FB018 single-chip CMOS microcontroller is designed for high performance using Samsung' s newest 8-bit CPU core, CalmRISC. CalmRISC is an 8-bit low power RISC microcontroller. Its basic architecture follows Harvard style, that is, it has separate program memory and data memory. Both instruction and data can be fetched simultaneously without causing a stall, using separate paths for memory access. Represented below is the top block diagram of the CalmRISC microcontroller.