NoX: a Compact Open-Source RISC-V Processor for Multi-Processor Systems-on-Chip

Abstract

The NoX processor is a compact, open-source, 32-bit RISC-V core designed in System Verilog to serve as a plug-and-play solution for Multi-Processor Systems-on-Chip (MPSoCs) targeting edge computing and IoT applications. It utilizes an efficient resource-constrained architecture featuring a 4-stage single-issue in-order pipeline with full bypass capability. NoX addresses the difficulty of seamlessly integrating current open-source cores and is shown to offer an improved balance between resource utilization and performance compared to existing resource-constrained cores.

Report

Key Highlights

• NoX is a compact, open-source, 32-bit RISC-V core specifically engineered for efficient data processing within Multi-Processor Systems-on-Chip (MPSoCs).
• It is designed as a "plug-and-play" component, addressing the challenge of seamlessly integrating existing open-source cores into MPSoC architectures for rapid time-to-market.
• The primary application target is resource-constrained edge computing and IoT systems that require high energy and power efficiency.
• The core achieves a superior trade-off between resource usage and performance when benchmarked against comparable resource-constrained RISC-V cores from industry and academia.

Technical Details

• Architecture: 32-bit RISC-V core.
• Implementation Language: Designed using System Verilog.
• Pipeline Structure: 4-stage, single-issue, in-order pipeline.
• Optimization Feature: Includes full bypass (data forwarding) capability to enhance efficiency and minimize pipeline stalls.
• Design Goal: To provide an efficient, resource-constrained architecture suitable for dense MPSoC deployment in resource-limited environments.

Implications

• Accelerated MPSoC Development: By providing a readily integrable, plug-and-play core, NoX significantly reduces the complexity and integration effort required for building custom RISC-V MPSoCs, thereby speeding up time-to-market.
• Edge Computing Enablement: The core specifically supports the architectural shift toward local processing (edge computing) in IoT applications, helping mitigate critical issues related to security, latency, and transmission delays associated with reliance on remote resources.
• Strengthening the RISC-V Ecosystem: NoX contributes a highly optimized, compact, and verified open-source option to the RISC-V IP library, broadening the appeal of RISC-V in deeply embedded, resource-constrained, and multi-core systems.
• Improved Efficiency Benchmark: The demonstrated ability to optimize resource usage relative to performance sets a new standard for resource-constrained open-source RISC-V core designs.