HyperCroc: End-to-End Open-Source RISC-V MCU with a Plug-In Interface for Domain-Specific Accelerators

TL;DR

HyperCroc is an open-source RISC-V-based microcontroller platform that integrates high-bandwidth memory interfaces and accelerators, enabling efficient data movement and domain-specific processing for machine learning and signal processing applications.

Contribution

It introduces HyperCroc, a novel open-source MCU with integrated HyperBus and DMA, supporting plug-in accelerators and validated through first silicon measurements.

Findings

Full chip implementation in under one hour on standard workstation

Silicon operates at 72 MHz @ 1.2 V confirming functionality

First silicon measurements validate the design flow and performance

Abstract

Domain-Specific architectures with accelerators for machine learning and signal processing require efficient bulk data movement and high-bandwidth access to large datasets. Such capabilities are often absent from minimal open-source microcontrollers (MCUs). We present HyperCroc, an extension to the end-to-end open-source RISC-V Croc system-on-chip (SoC) integrating a silicon-proven HyperBus controller for off-chip DRAM and Flash memory access and a DMA engine, providing a practical MCU-class platform with streamlined plug-in support for domain-specific acceleration. HyperBus offers a low-pin-count PSDRAM interface at up to 400 MB/s, enabling bandwidth-scaled dataset access, while the DMA engine enables autonomous, high-throughput transfers without CPU intervention. HyperCroc preserves Croc's open-source synthesis and physical implementation flow targeting IHP's open 130 nm process design kit (PDK); the full chip can be implemented in under one hour on a consumer-grade workstation. We further report first silicon measurements from MLEM, the first Croc tapeout, confirming that the silicon is fully functional at 72 MHz @ 1.2 V and validating the end-to-end flow.