Croc: An End-to-End Open-Source Extensible RISC-V MCU Platform to Democratize Silicon
Phillippe Sauter, Thomas Benz, Paul Scheffler, Hannah Pochert, Luisa Wüthrich, Martin Povišer, Beat Muheim, Frank K. Gürkaynak, Luca Benini
TL;DR
Croс addresses the need for open, end-to-end silicon platforms to democratize chip design by delivering an education-focused RISC-V MCU platform called Croc. Built around a production-ready CVE2-based core, Croc provides a streamlined synthesis- and implementation-flow, a modular hardware/software co-design environment, and an end-to-end flow suitable for classroom use. The paper demonstrates viability through the MLEM tapeout on IHP's open 130 nm node and highlights upcoming adoption in ETH Zurich's VLSI courses with CC-licensed teaching materials. Collectively, Croc aims to bridge teaching and industry, lowering entry barriers and enabling scalable end-to-end silicon education and ISA-extension experiments.
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.