【CK801 Embedded CPU —— The Smallest C-SKY Processor】
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）。
Main technical features of CK801
· Extremely reduced instruction set computer architecture, 32-bit data, 32/16-bit variable length instructions
· 70+ core instructions, including 55 16-bit instructions
· Performance: 0.6 DMIPS/MHz
· 2-stage extremely low cost pipeline, single issue in-order execution
· One-cycle execution delay for all instructions
· Von Neumann architecture, single-bus shared by instruction and data access
· Configurable hardware multiplier
· 14 cycles Interrupt latency from interrupt asserting to interrupt handler processing
· Memory access protection, 0——8 hardware configurable memory protection
· Tightly-coupled IPs, including vector interrupt controller, timer and power management unit
· Trusted execution technology against software attack
· Configurable hardware debugger supporting on-chip debugging
Application fields of CK801
· Internet of Things （IoT）
· Low cost MCU
· Smart sensor
Micro architecture and key features
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.
CK801 is compatible with other CK800 CPU in binary code and programming mode for portability.
CK801 provides tightly-coupled system IP modules, including vector interrupt controller and timer to facilitate SoC integration and software porting. Vector interrupt controller supports 1/2/4/8/16/32 interrupt sources triggered by level or pulse. Nested interrupt is implemented to increase the real-time performance. The timer module supports a 24-bit timer.
Trusted execution technology for IOT security
For IoT security, CK801 has developed the trusted execution technology based on virtualized trusted world and non-trusted world, which protects secure data in trusted world. It offers multiple layers of trusted protection features including trusted interrupt response and trusted debugging.