RISC-V Hardware Synthesizable Processor Design Test and Verification Using User-Friendly Desktop Application

Abstract

Although the RISC-V ISA has not been around for long, it is a processor architecture that has been highlighted by many businesses and individuals for its low-cost and rapid pace of development. They are open-source-synthesizable hardware processors with minimal functionality that is ideal for current IoT applications involving simple sensors and actuator controls. Due to some qualities of hardware, they can operate in areas where software programs and applications cannot be used whereas, these software programs that run on such hardware equally help in understanding how hardware operates. This paper, therefore, proposes and discusses the design, implementation, and internal verification and test platform for a Reduced Instruction Set Code-V’s (RISC-V) Instruction Set Architecture (ISA), using an interactive desktop program for a 32-bit single-cycle processor. This paper developed a system that functions as interactive assistance to RISC-V's ISA design and debugger using a more user-friendly desktop UI application. The uniqueness of this design is the flexibility of testing and debugging that is possible through either the software interface or through hardware peripherals such as Universal Asynchronous Receiver/Transmitter (UART) protocols in FPGA or even both. These peripherals allow users to view the contents of the register files and RAM being utilized by the implemented processor on the FPGA. The proposed desktop User Interface program monitors and controls the sequential processing and states of a 32-bit single-cycle RISC-V processor’s operation on an FPGA. Contents of the proposed processor’s registers and memory are displayed alongside other temporal or internal data. Internal components such as Program Counters (PC), Random Access Memory (RAM), are displayed all through the proposed User Interface (UI) program and also through various peripherals on the FPGA board. The software program is implemented using C# programing language through Microsoft Visual Studio 2019 Integrated Development Environment (IDE). The proposed hardware synthesizable processor core is implemented using Verilog Hardware Description Language (HDL) and synthesized with Xilinx Integrated Synthesis Environment (ISE) version 14.7. The proposed processor and its corresponding hardware test modules occupy 6476 Look-Up-Tables (LUT) and operate at a maximum frequency of 49MHz and its operation is verified on a Field Programmable Gate Array (FPGA). The proposed processor and its test platform can serve as a good educational tool as well as a help for processor design engineers both experienced and beginners.