Seamless SPI Integration for 12-axis Robot
01. Seamless SPI Integration for 12-Axis Industrial Robot Using STM32H7
This project focused on developing a robust SPI communication backbone for a 12-axis robotic arm using the STM32H7 series microcontroller. With multiple motors and sensors needing precise coordination, our goal was to ensure ultra-reliable, low-latency data exchange between motor drivers, encoders, and the main control unit. Leveraging the powerful features of the STM32H7—such as high-speed SPI, dual-core architecture, and DMA—we delivered a deterministic and scalable firmware solution for complex multi-axis motion control.
02. Things used in this project
Building firmware for a 12-axis robot presented several challenges:
Synchronizing SPI data streams across multiple devices with minimal latency
Handling high-frequency encoder feedback and real-time motor commands
Preventing communication bottlenecks across SPI buses
Ensuring deterministic behavior despite simultaneous data transactions
To address these, we utilized multi-threaded FreeRTOS tasks and DMA-driven SPI transactions, allowing simultaneous communication without CPU blocking. Each SPI bus was isolated to a specific axis group, with priority queues for command dispatch. We also implemented custom CRC-based validation to catch miscommunication during high-speed exchanges.
03. Story
We began by benchmarking the STM32H7’s SPI capabilities under different clock speeds and loads. Based on system requirements, we segmented axes into SPI zones and routed communication through dedicated SPI peripherals. The firmware design included:
DMA-enabled SPI transfers for fast, non-blocking communication
ISR-based feedback handling for encoder inputs
Real-time control loops for synchronized actuation across axes
Modular driver architecture for scalability and future expansion
Extensive testing ensured each axis responded within microseconds of command dispatch, even during full system load. Stress tests validated the integrity of communication under noisy industrial environments. The final system delivered ultra-smooth, deterministic motion control—paving the way for precise, industrial-grade robotic automation.