The 80251 CPU IP core is an instruction set compatible implementation of the MCS-251 family. The 80251 core executes the instruction in a single clock cycle, and is on average about 3.19 times faster than the original implementation. The performance improvements are due to architectural enhancements done to the CPU core. The I/O ports of the IP core have been simplified by removing unnecessary muxing on the ports to make it fully compatible with today's system on chip (SoC) design practices.