RISC-V Resource-Constrained Cores: A Survey and Energy Comparison

Abstract

Resource-Constrained electronic devices targeting IoT applications need a microcontroller to control their operation, and hence this microcontroller should be energy efficient to increase battery life. One of the emerging open-source processors ISA is RISC-V; as an open-source, it provides a great opportunity for innovation and creativity in designing processor cores. This study targets to survey open-source RISC-V cores and classify them as high-performance and resource-constrained. Afterward, we shortlist the most optimized cores for resource-constrained devices. Seven shortlisted cores are implemented using an ASIC prototyping platform as a unified technology and are compared using resource utilization and energy consumption profile to find the most energy efficient core. We proposed a method to evaluate the energy consumption using power and performance values. Results showed Ibex core to have the best energy consumption characteristics with 8.7 Coremark iterations/mJ over the ASIC prototyping platform.