Croc: An End-to-End Open-Source Extensible RISC-V MCU Platform to Democratize Silicon

TL;DR

Croc is an open-source, extensible RISC-V microcontroller platform designed to democratize chip design education and innovation through an end-to-end open-source flow and real-world tapeout demonstrations.

Contribution

The paper introduces Croc, a fully open-source, extensible RISC-V MCU platform with an end-to-end design flow, enabling hands-on teaching and rapid chip development.

Findings

Successful tapeout of Croc in 8 weeks with 2 students

Used in university curriculum with up to 80 students

Produced multiple OS-based chip layouts and system-on-chip tapeouts

Abstract

Ensuring a continuous and growing influx of skilled chip designers and a smooth path from education to innovation are key goals for several national and international "Chips Acts". Silicon democratization can greatly benefit from end-to-end (from silicon technology to software) free and open-source (OS) platforms. We present Croc, an extensible RISC-V microcontroller platform explicitly targeted at hands-on teaching and innovation. Croc features a streamlined OS synthesis and an end-to-end OS implementation flow, ensuring full, unconstrained access to the design, the design automation tools, and the implementation technology. Croc uses the industry-proven, open-source CVE2 core, implementing the RV32I(EMC) instruction set architecture (ISA), enabling students to define and implement their own ISA extensions. MLEM, a tapeout of Croc in IHP's open 130 nm node completed in eight weeks by a team of just two students, demonstrates the platform's viability for hands-on teaching in schools, universities, or even on a self-education path. In spring 2025, ETH Zurich will utilize Croc for its curricular VLSI class, involving up to 80 students, producing up to 40 OS application-specific integrated circuit layouts, and completing up to five student-led system-on-chip tapeouts. The lecture notes and exercises are already available under a Creative Commons license.