The M8051 is a configurable soft-core implementation of the industry standard 8051 microcontroller that features a clock compatible twelve clocks per machine cycle architecture. This microcode-free design is software compatible (including instruction execution times) with industry standard discrete devices, having all their core features, and the additional features corresponding to the Intel 8051/8031/80C51BH/80C31BH/87C51 parts except that ONCE mode and Program Lock are not supported. The use of standard synchronous design methodology makes this core simple to integrate into both ASIC and FPGA SoC designs.