These cores have been specifically designed to cater to the dynamic needs of the Internet of Things (IoT) and embedded systems.
The D23 and N225 cores have been engineered with compactness, performance-efficiency, low-power consumption, flexibility, and security as top priorities and they look to support IoT and embedded chip and device manufacturers while reducing power usage and ensuring improved levels of security.
Andes announced the popular N22 back in February 2019, and the D23 and N225 are revamped designs with a new microarchitecture and the latest RISC-V extensions to offer better performance, smaller code size, and more security support. They provide a good migration path for customers looking to upgrade their N22 designs or who are looking at a new design.
The N225 implements the RV32 IMACBZce non-privileged extensions as well as Machine/User modes and Enhanced Physical Memory Protection (ePMP), while D23 also supports the FDKP extensions (Single/Double-Precision Floating-Point, Scalar Crypto and Packed SIMD/DSP draft), and CMO (Cache Management Operations) extension. The D23 is also incorporated with Supervisor mode and its associated PMP (sPMP) for higher security.
Both cores feature a highly compact design with a 3-stage pipeline, primarily supporting single instruction issue with some dual-issue capability, which makes them well-suited for space- and memory-constrained IoT and embedded applications.
Both cores can achieve industry-leading performance in their class, boasting outstanding benchmark scores such as 4.55 (D23) and 4.4 (N225) Coremark/MHz, and 2.08 (D23) and 1.92 (N225) DMIPS/MHz, respectively. They are capable of operating at high frequencies across various technology nodes such as near 800 MHz at 28nm, providing the necessary computing power for edge IoT devices with ever-increasing performance and feature demands.
Both cores support advanced power management technologies such as PowerBrake and Wait-For-Interrupt (WFI) and Wait-For-Event (WFE), ensuring prolonged battery life for many types of untethered IoT devices.
The N22 already offers industry-leading code size with Andes CoDense technology. With the addition of the new RISC-V Zce code size reduction extension, the D23 and N225 further reduce 4.4% code size for the Embench-IoT benchmark, compared to the N22.
Both cores also offer extensive configurability, including optimised multipliers for performance or area, optional static or dynamic branch prediction, various combinations of privilege modes, instruction and data Local Memories with sizes from 1 KB to 512 MB, and 2-wire or 4-wire JTAG debug interface. Designers can tailor these features to address their specific application requirements.
To simplify integration into System-on-Chip (SoC) designs, both cores support either Core-Local Interrupt Controller (CLIC) for the single-CPU SoC or Platform-level Interrupt Controller (PLIC) for multiple-CPU SoC, rich options for AMBA interfaces, private machine timers or platform machine timers, and instruction trace interfaces.
In addition to the above-mentioned shared features and latest RISC-V extensions, the D23 core boasts additional capabilities, including built-in instruction and data caches, and ECC soft error protection for all cache and local memories. It can also seamlessly integrate with the powerful ACE (Andes Custom Extension) to support custom instructions for Domain-Specific Acceleration (DSA) and has a roadmap to include a functional safety derivative. These expanded capabilities open up opportunities for the D23 to serve a wider range of segments in automotive and industrial control applications.
Commenting on the release Dr. Charlie Su, President and CTO of Andes Technology, said, “The D23 and N225 mark a significant milestone in our commitment to providing innovative solutions for the IoT and embedded segments. With their compact design, power efficiency, and robust security features, these cores are poised to set new industry standards. We believe they will empower designers and developers to create cutting-edge products that can thrive in the fast-paced world of IoT.”
The D23/N225 have been licensed out and several companies are actively evaluating them.
