Sink-only USB PD 3.2 stack for embedded systems: SPR + EPR, with a core free of platform and vendor dependencies.
This library focuses on the most common needs of PD‑powered projects and on ease of use.
Features:
- USB PD Rev 3.2 with SPR and EPR modes (sink side).
- Platform-agnostic C++ core.
- Reference implementation: FUSB302B + FreeRTOS.
- MIT license.
Not supported:
- Source role (SRC) and related modes (DRP/DFP/FRS/Alt).
A lot of embedded designs only need one thing: to be a sink and behave correctly. In practice, available PD stacks usually come with at least one hard constraint:
- vendor lock-in / NDA / no public sources,
- tied to a specific OS or framework,
- incomplete sink-side feature coverage (e.g., no EPR support or poor spec compliance),
- difficult to extend to new TCPC/MCU combinations.
This library addresses these constraints through a sink-focused implementation and aims to improve adoption in modern embedded projects.
- Status: early stage; sink path validated on FUSB302B + FreeRTOS.
- Coverage: SPR/PPS/EPR sink negotiation validated on the current reference path.
- Seeking: validation on additional TCPC/MCU combinations.
- Real-world use: integrated into the Reflow Micro Table firmware (heater control path).
- Current reference path:
examples/fusb302_rtos_esp32c3_arduino(FreeRTOS, ESP32-C3, FUSB302). - For a complex real-world scenario, see the heater-related classes in the Reflow Micro Table project.
This project can help when:
- you need dynamic power control at runtime (heaters, for example).
- you want to use an MCU with an embedded UCPD and simplify external components.
- you need “non-standard” voltages or current limits (via PPS/AVS profiles).
If you only need a single fixed profile, a simple PD trigger (e.g., CH224 or a similar external trigger) can be a more rational choice.
Project scope: sink role only. The non-goals in Not supported are intentional.
Other projects with USB PD support:
Documentation: