Tweede Golf developed a proof-of-concept universal hardware-in-the-loop (HIL) test suite for Rust hardware abstraction layers (HALs). The system uses an RP2040-based Arduino Shield as a tester microcontroller to emulate interfaces like UART, I2C, and SPI with precise timing via PIO, connected to a device under test. A host-side Rust program compiles both firmwares, flashes them via probe-rs, and collects results over RTT/defmt without reflashing between tests. The team also designed a custom PCB housing two RP2354B MCUs, a USB hub, and power measurement. The PoC successfully uncovered a real ESP32-C6 I2C timeout bug. Next steps include expanding coverage to all embedded-hal and embedded-io traits and improving UX, with funding being sought.
