CK801 is an ultra-low cost and low power embedded CPU core among CK800 series. Based on C-SKY V2 instruction set architecture and 16/32-bit variable length instruction system, CK801 only implements 70+ instructions to optimize code density, area cost and power efficiency. Moreover, CK801 realizes an extreme low cost 2 stage pipeline. CK801 family includes basic core (CK801) and trusted execution extension (CK801T).

CK801 implements an extremely reduced instruction sets including only 55 16-bit instructions and near 20 32-bit instructions (e.g., branch and privileged instructions). The minimum core area of CK801 is 9,000 gates. CK801 adopts an extremely simplified 2-stage pipeline micro architecture, and optimizes resources by reusing registers and execution units. Complex instructions are splitted into several atom operations to minimize cost and power while satisfying performance requirements.