HAPS-to-Host: Seamless FPGA Prototyping for Full-Stack System-on-Chip Validation

The Always-On Subsystem (AOS) is a foundational component for modern mobile platforms, integrating processing cores, memory, and peripheral controllers to support low-power audio and sensor processing while managing complex I/O tasks. However, traditional hardware emulation often faces challenges to accurately model and test the analog modules—such as PHYs—that are essential for real-world I/O connectivity in audio systems. This paper proposes a robust FPGA prototyping system for a System-on-Chip’s Always-On Subsystem (AOS) to bridge this gap. Serving as a high-fidelity platform for accelerating pre-silicon software development, this low-power audio and sensor processing hub enables comprehensive design verification and optimizes the full software stack. This methodology facilitates the tuning of production software—including booting Android and testing the Device Audio stack—prior to costly silicon fabrication by achieving higher clock speeds.
The proposed prototyping platform utilizes the Synopsys HAPS-100 system to accurately model the AOS RTL design, encompassing all internal components and interfaces at higher operating speeds. This high-speed environment provides a robust hardware abstraction layer, enabling software execution that mirrors silicon behavior. To support a comprehensive mobile platform environment, the architecture facilitates the following critical connectivity:
Application Processor Communication: A PCIe Gen1 connection to the Host Platform enables the execution of production-level ISA software and supports the development of host-side AOS drivers and Android configurations.
Real-World I/O: A dedicated daughter card interfaces external components to the AOS via the HT3 connector, allowing for the integration of physical microphones, speakers, and sensors for realistic scenario simulation.