STMicroelectronics expand STM32U5 series

The new MCUs extend the range of code and data storage to 128Kbyte Flash for cost-sensitive applications, while also adding high-density versions for complex applications and sophisticated smartphone-like user interfaces. Among these, the STM32U59x/5Ax with 4Mbyte Flash and 2.5Mbyte SRAM has the largest on-chip memory of any STM32 MCU to date.

With their increased capabilities, the new MCUs enhance deeply embedded applications like environmental sensors, industrial actuators, building automation, smart appliances, wearable devices, eMobility controls, and others, especially in remote, difficult-to-access locations. As billions of such devices are being deployed worldwide for smart living and working, ST’s new MCUs accelerate progress by boosting performance, enhancing energy efficiency, and strengthening cybersecurity.

All STM32 MCUs are based on industry-standard Arm Cortex-M embedded CPU cores and benefit from the powerful and easy-to-use STM32Cube and STM32Cube.AI development ecosystem. This ecosystem consolidates tools and software to support customers’ projects from start to finish, including the creation of cutting-edge AI/ML solutions through the conversion of pre-trained neural networks into optimised code.

The STM32U5 series leverages the latest generation, the Cortex-M33, which incorporates advancements that increase performance, energy efficiency, and resistance to online and hardware attacks. Around this core, ST has added its ultra-low-power MCU know-how and implemented an architecture that leverages established Arm principles for superior cybersecurity. Some devices in the series provide a 2.5D graphics accelerator. The result is a MCU series that offers a large selection of pin-to-pin and software-compatible products ready to tackle next-generation applications.

“Because many applications demand extra functionality, richer graphics, and faster performance while running longer, using a smaller battery, or employing energy harvesting, we’ve developed the STM32U5 and are extending the series, today,” said Ricardo De Sa Earp, Executive Vice President General-Purpose Microcontroller Sub-Group, STMicroelectronics. “This MCU combines the latest Arm core, our unique ultra-low-power technologies, generous on-chip memory, and the option of our NeoChrom graphics engine to elevate the user’s visual experience.”

Among ST’s lead customers for the STM32U5 series, Ajax Systems is already designing future generations of its advanced wireless security and smart home solutions using the new MCUs. Max Melnyk, Device Department R&D Director at Ajax, commented, “Working with STMicroelectronics, a global giant in the semiconductor market, helps us evolve and strengthen Ajax products. The STM32U5 series significantly lowers power consumption while maintaining the same performance we achieved using other MCUs that contain DSP and floating-point co-processors. And we can reuse 90% of our existing code. An additional, major advantage for us is the large integrated SRAM, which is enough to handle a double frame buffer for fast and fluid graphics performance. There is also a generous flash for loading resources. I’m sure it’ll drive the development of the next generations of Ajax products.”

Further technical information

Proprietary energy-saving features of the STM32U5 series include autonomous peripherals and ST’s low-power background autonomous mode (LPBAM). The LPBAM lets the application maintain critical functionality while the core and other unused blocks power down into any of the MCU’s flexible energy-saving modes. From this state, the MCU can quickly wake the core to process a batch of data efficiently and then transition back into a low-power mode.

On the other hand, STM32U5 MCUs provide up to 4Mbytes of flash storage for code and data, as well as up to 2.5Mbytes SRAM, for handling sophisticated applications. The large on-chip memory saves additional discrete memory chips that otherwise increase power consumption, bill-of-materials (BOM) cost, and PCB size.

The STM32U5 series also breaks the constraints on graphics performance that typically apply to ultra-low-power MCUs. Variants with ST’s advanced NeoChrom GPU on-chip can run a sophisticated GUI previously only possible with an expensive microprocessor-based system. A tiny, embedded processor can now host smartphone-like user experiences and GUI development can leverage ST’s TouchGFX framework that now features SVG support and rich graphical assets.

Also, unlike the processors typically needed to support such sophisticated capabilities, STM32U5 MCUs come in an economical LQFP100 package that permits a simplified PCB construction with minimal layer count. Developers can accelerate their projects using resources including the STM32CubeU5 software package, new NUCLEO-U545RE and NUCLEO-U5A5ZJ development boards, and the STM32U5A9J-DK Discovery kit for graphics.

The STM32U5 series also enhances cyber security, leveraging the Cortex-M33 with its memory protection unit and Arm’s TrustZone architecture featuring hardware isolation. The MCUs also integrate cryptographic accelerators for advanced AES algorithms, support for public key architecture (PKA), and resistance to physical attacks. In addition, error correction code (ECC) support on flash and SRAM prevents corruption thereby enhancing both cyber-protection and safety.

On top of this, the STM32U5 is the first general-purpose group of MCUs to receive the NIST (US National Institute of Standards and Technology) embedded random-number entropy source certification. As the certification is reusable by customers, it simplifies and speeds certification for those applications that need SP800-90B final certification.

The new STM32U5 devices are scheduled to begin volume production in Q2 2023. MCUs will be available from ST’s eStore and distributors, priced from $2.15 for orders of 10,000 pieces. Please contact your local ST sales office for other pricing options.