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Talk Intermediate CC BY-SA 4.0 First Talk

From Architecture to Tasks: Designing Real-Time MCU Firmware in Heterogeneous APU-MCU Systems

Proposal status is Approved
Session Description

People are now familirized to rich UI hence the embedded devices are required to meet those standards. Many embedded products today need two very different things at once: a rich user interface, connectivity, and application logic and a hard real-time behavior with strict timing guarantees (best served by a dedicated MCU running an RTOS or bare-metal firmware). In this talk I want to walk through a real heterogeneous multi-processing (HMP) architecture built around this split: an STM32MP1 running Linux for display and application-level functionality, paired with an STM32H7 microcontroller handling the real-time subsystem, including sensor data acquisition, motor control data management and other periphearl activities.

We'll start by examining why this split was the right call, then go inside the custom IPC layer connecting the two chips: how the protocol was designed (framing, message types, error handling), and how failures like an independent reset on either side are managed.

The next section zooms into the H7 firmware, covering RTOS task design patterns that keep the real-time subsystem deterministic: ISR-to-task deferral for sensor sampling, event-driven patterns and command queue architectures that decouple incoming Linux-side commands from time-critical control loops.

Finally, we'll discuss how designing the IPC layer around a stable, well-defined protocol enables a modular hardware architecture. the real-time subsystem can remain unchanged while the application processor side is swapped for a different MPU or APU (for example, one better suited to display or AI workloads), as long as it speaks the same protocol.

Key Takeaways

  • When and why to split a product's compute across an APU (Linux, display/connectivity/application logic) and an MCU and how to evaluate that tradeoff for your own designs

  • Practical RTOS task design patterns for the real-time subsystem:

  • How a well-defined IPC protocol enables a modular hardware architecture, allowing the application processor (APU/MPU) to be swapped or upgraded independently without touching the real-time subsystem

  • A reusable framework for thinking through HMP and RTOS architecture decisions on future products, balancing real-time guarantees, scalability, and long-term flexibility

References

https://www.linkedin.com/in/udhayadhithan/

Session Categories

Engineering practice - productivity, debugging
Technology architecture
Talk License: CC BY-SA 4.0

Which track are you applying for?

Real Time Operating Systems (RTOS)

Speakers

udhayadhithan PA Chief Technology Officer | Thynkloop

Udhayadhithan is the Co-Founder and CTO of ThynkLoop. Thynkloop is an embedded systems and AIoT engineering services company based in Chennai. He leads technical architecture and product development across a range of hardware and firmware projects, working at the intersection of embedded software, real-time systems, and hardware design for industrial and consumer products. He has his experience in full product development lifecycle, from initial architecture through firmware, PCB design, and production. He is also a co-founder of Thynkure Medical, a pre-clinical medical device startup with a mission to help tier 2 and tier 3 hospitals get the advance care.
udhayadhithan PA
https://www.linkedin.com/in/udhayadhithan/