IEEE GCCE 2021 — An Energy Efficient Processor Applicable to Continuous SpO2 Monitoring

UNO Laboratories and Hirosaki University presented joint research results at IEEE GCCE 2021 (2021 IEEE 10th Global Conference on Consumer Electronics). The paper demonstrated that the single-stage RISC-V processor (RV32IM) achieves sufficient performance for continuous SpO2 monitoring while operating at ultra-low power. This research formed the basis for the verified result of 2+ days of continuous SpO2 monitoring on a single AA NiMH rechargeable battery, which remains one of Trinita®'s most compelling real-world demonstrations.

IEEE GCCE 2021: https://ieeexplore.ieee.org/document/9621795

【Reference】
Implementation of the single-stage RISC-V Processor (RV32IM) on Xilinx®Artix®-7 100T FPGA
Proven Dhrystone benchmark energy consumption (J) of 6.4% of Xilinx® Micro Blaze™ (5-stage pipeline)
【Update】This verification result is based on the CPU registers configured with FF, but as of 2024, the CPU registers are configured with BRAM, achieving even higher power efficiency.

【Arty-A7 100T ENERGY CONSUMPTION TO COMPLETE DHRYSTONE BENCHMARK】
※Running Dhrystone benchmark program (version 2.2) 512,000 times
※Operating frequency：25MHz

・Single-Stage：Runtime 8.3（sec）　Energy consumption 0.224（J）
・Micro Blaze ：Runtime 32（sec）　Energy consumption 3.488（J）

※To demonstrate the practicality of the above single-stage RISC-V processor, we have incorporated it into a pulse oximeter and demonstrated that continuous monitoring of SpO2 for more than two days is possible with a single AA NiMH rechargeable battery.