Núñez-Prieto Ricardo, Castells-Rufas David, Terés-Terés Lluís
Barcelona Supercomputing Center (BSC), 08034 Barcelona, Spain.
Microelectronics & Electronic Systems Department, Universitat Autònoma de Barcelona (UAB), 08193 Cerdanyola del Vallès, Spain.
Micromachines (Basel). 2023 Jul 4;14(7):1371. doi: 10.3390/mi14071371.
In the field of embedded systems, energy efficiency is a critical requirement, particularly for battery-powered devices. RISC-V processors have gained popularity due to their flexibility and open-source nature, making them an attractive choice for embedded applications. However, not all RISC-V processors are equally energy-efficient, and evaluating their performance in specific use cases is essential. This paper presents RisCO2, an RISC-V implementation optimized for energy efficiency. It evaluates its performance compared to other RISC-V processors in terms of resource utilization and energy consumption in a signal processing application for nondispersive infrared (NDIR) CO sensors.The processors were implemented in the PULPino SoC and synthesized using Vivado IDE. RisCO2 is based on the RV32E_Zfinx instruction set and was designed from scratch by the authors specifically for low-power signal demodulation in CO NDIR sensors. The other processors are Ri5cy, Micro-riscy, and Zero-riscy, developed by the PULP team, and CV32E40P (derived from Ri5cy) from the OpenHW Group, all of them widely used in the RISC-V community. Our experiments showed that RisCO2 had the lowest energy consumption among the five processors, with a 53.5% reduction in energy consumption compared to CV32E40P and a 94.8% reduction compared to Micro-riscy. Additionally, RisCO2 had the lowest FPGA resource utilization compared to the best-performing processors, CV32E40P and Ri5cy, with a 46.1% and a 59% reduction in LUTs, respectively. Our findings suggest that RisCO2 is a highly energy-efficient RISC-V processor for NDIR CO sensors that require signal demodulation to enhance the accuracy of the measurements. The results also highlight the importance of evaluating processors in specific use cases to identify the most energy-efficient option. This paper provides valuable insights for designers of energy-efficient embedded systems using RISC-V processors.
在嵌入式系统领域，能源效率是一项关键要求，对于电池供电设备而言尤为如此。RISC-V处理器因其灵活性和开源特性而受到欢迎，成为嵌入式应用的一个有吸引力的选择。然而，并非所有RISC-V处理器都具有同等的能源效率，在特定用例中评估它们的性能至关重要。本文介绍了RisCO2，一种针对能源效率进行优化的RISC-V实现。它在用于非色散红外（NDIR）一氧化碳传感器的信号处理应用中，就资源利用率和能耗方面，与其他RISC-V处理器相比评估了其性能。这些处理器在PULPino SoC中实现，并使用Vivado IDE进行综合。RisCO2基于RV32E_Zfinx指令集，由作者专门为CO NDIR传感器中的低功耗信号解调从头设计。其他处理器包括PULP团队开发的Ri5cy、Micro-riscy和Zero-riscy，以及OpenHW Group的CV32E40P（源自Ri5cy），它们在RISC-V社区中都被广泛使用。我们的实验表明，RisCO2在这五个处理器中能耗最低，与CV32E40P相比能耗降低了53.5%，与Micro-riscy相比降低了94.8%。此外，与性能最佳的处理器CV32E40P和Ri5cy相比，RisCO2的FPGA资源利用率最低，查找表（LUT）分别减少了46.1%和59%。我们的研究结果表明，RisCO2是一款用于需要信号解调以提高测量精度的NDIR CO传感器的高能效RISC-V处理器。结果还突出了在特定用例中评估处理器以确定最节能选项的重要性。本文为使用RISC-V处理器的高能效嵌入式系统设计者提供了有价值的见解。
