Ultra-Low Power STM32 microcontrollers

The Ultra-Low power STM32 microcontrollers series is an offer for designers of applications and energy-efficient embedded systems. It provides a balance between performance, power, safety and cost-effectiveness. The portfolio includes STM8L (8-bit proprietary core), STM32L4 (Cortex®-M4), STM32L0 (Cortex®-M0+), STM32L1 (Cortex®-M3) and STM32L5 (Cortex®-M33). The STM32U5 microcontrollers with Cortex-M33 core are the latest addition to ST’s rich portfolio.


The STM32U5 series combines the latest and most efficient ARM Cortex-M33 core with an innovative 40nm technology. This reduces energy consumption while increasing performance. The series also adds the state-of-the-art features which are required in today’s applications, including advanced cyber security with hardware-based protection, and graphics accelerators for rich graphical user interfaces.

STM32U5 series offers up to 2 Mbytes of Flash (dual bank) memory and 786 Kbytes of SRAM. There are 8 packages types available (from 48 to 169 pins). The upper operating temperature range reaches 125°C.


The main features that distinguish this series from others:

  1. Enabling best-in-class power consumption
  •   energy benchmark:
    – 535 ULPMark-CP,
    – 149 ULPMark-PP,
    – 58 ULPMark-CM,
    – 133000 SecureMark-TLS.
  • LPBAM (Low Power Background Autonomous Mode) – an innovative, autonomous power mode, saves power by enabling direct memory access (LPDMA Low Power Direct Memory Access) and ensuring the peripherals keep working, while most of the device is in stop mode,
  • embedded SMPS (Switched-Power Mode Supply) step-down converter (optional)
  • current consumption:
    – 110nA in shutdown mode,
    – 300nA in standby mode,
    – 1.7µA in stop mode 3 with 16 Kbytes of SRAM,
    – 6.6µA in stop mode 2 with 786 Kbytes of SRAM,
    – down to 19µA/MHz in active mode.
  1. Enhanced security

Building on the cyber security features of the STM32L5 MCU with its ARM Cortex-M33 core that incorporates ARM’s TrustZone® technology and an ST’s specific security feature set, the STM32U5 series introduces state-of-the-art innovations:
– AES encryption and Public Key Accelerator (PKA) are now side-channel hardware resistant,
– Secure data storage with a HUK (Hardware Unique Key),
– Active tamper detection. Internal monitoring, that can erase secret data in the event of perturbation attacks, helps meet the PCI Security Standards Council (PCI SSC) requirements for Point Of Sales (POS) applications,
– PSA Certified level 3 and SESIP (Security Evaluation Standard for IoT Platforms) level 3 certified.


  1. Integration, size and performance
  •  ensures enhanced application responsiveness:
    – ARM Cortex-M33 core running at 160 MHz,
    – new ST ART Accelerator: working both on internal and external Flash (8 Kbytes of instruction cache),
    – 240 DMIPS and 651 CoreMark scores.
  • up to 0.5 Mbytes of on-chip Flash offers increased cycle life, up to 100,000 read/write cycles to ensure reliable storage of user data,
  • high integration and innovation: large memory with ECC on Flash and SRAM, USB Type-C w/power delivery controller, CAN FD, 14- and 12-bit ADC, Multi-function Digital Filter (MDF) and Audio Digital Filter (ADF)
  • 8 packages types (LQFP48, QFN48, LQFP64, WLCSP90, LQFP100, UFBGA132, LQFP144 and UFBGA169).

 STM32U5 development tools

  1. The STM32U575I-EV evaluation board – full feature set

The board is based on an ultra-low-power STM32U575AII6Q microcontroller with 2 Mbytes of Flash memory and 786 Kbytes of SRAM, one external memory interface supporting an LCD interface, two Octo-SPI memory interfaces, one USB Type-C® 2.0 FS device and host with Power Delivery controller interface (UCPD), one camera interface, one SDMMC interface, one 14-bit and one 12-bit ADCs, two 12-bit DACs, two operational amplifiers, two ultra‑low‑power comparators, four digital filters for sigma‑delta modulation, MEMS sensors (microphone, accelerometer, gyroscope), up to 16 timers, touchkey capability, and SWD, JTAG, and ETM interface debugging support.

The full range of hardware features on the STM32U575I-EV evaluation board helps the user to develop applications and evaluate all the peripherals, such as USB Type-C® connector with USB PD, motor control connector, CAN FD transceiver, USB 2.0 FS, RS-232, audio DAC, microphone ADC, dot-matrix TFT LCD, IrDA, IR LED, IR receiver, LDR, SRAM, camera interface, Octo-SPI Flash memory, microSD™ card, sigma-delta modulators, Smartcard slot, I2C, and EEPROM.

The daughterboard and extension connectors provide an easy way to connect a daughterboard or wrapping board for the user’s specific application.

Furthermore, the onboard STLINK-V3E debugger provides out‑of‑the‑box loading and debugging capabilities, as well as a USB Virtual COM port bridge.

  1. The B-U585I-IOT02A Discovery board – direct connection to cloud services

The B-U585I-IOT02A Discovery kit provides a complete demonstration and development platform for the STM32U585AI microcontroller, featuring an ARM® Cortex®-M33 core with ARM® TrustZone® and Armv8-M mainline security extension, 2 Mbytes of Flash memory and 786 Kbytes of SRAM, as well as smart peripheral resources. This Discovery kit enables a wide diversity of applications by exploiting low-power communication, multiway sensing, and direct connection to cloud servers.

It includes Wi-Fi® and Bluetooth® modules, as well as microphones, temperature and humidity, magnetometer, accelerometer and gyroscope, pressure, time-of-flight, and gesture-detection sensors.

The support for ARDUINO® Uno V3, STMod+, and Pmod™ connectivity provides unlimited expansion capabilities with a large choice of specialized add-on boards.

For even more user-friendliness, the on-board STLINK-V3E debugger provides out-of-the-box loading and debugging capabilities, as well as a USB Virtual COM port bridge.

The B-U585I-IOT02A Discovery kit leverages the STM32U5 Series key assets to enable prototyping for a variety of wearable or sensor applications in fitness, metering, industrial, or medical, with state-of-the-art energy efficiency and higher security.

  1. The NUCLEO-U575ZI-Q board – affordable and quick prototyping

The STM32 Nucleo-144 board provides an affordable and flexible way for users to try out new concepts and build prototypes by choosing from the various combinations of performance and power consumption features, provided by the STM32 microcontroller. For the compatible boards, the internal or external SMPS significantly reduces power consumption in Run mode. The ST Zio connector, which extends the ARDUINO® Uno V3 connectivity, and the ST morpho headers provide an easy means of expanding the functionality of the Nucleo open development platform with a wide choice of specialized shields.

The STM32 Nucleo-144 board does not require any separate probe as it integrates the ST-LINK debugger/programmer.

The STM32 Nucleo-144 board comes with the STM32 comprehensive free software libraries and examples available with the STM32Cube MCU Package.


  1. The STM32Cube software package

The STM32Cube ecosystem is a complete software solution for STM32 products (MCU and MPU) that aims to increase developer productivity by reducing effort, time and cost. It includes a comprehensive embedded software platform provided for each STM32 series. STM32CubeIDE is a suite of environments that combines a graphical MCU configurator (STM32CubeMX) and a software development environment (SDK). STM32CubeMX can be installed separately and code can be generated independently for other environments (such as KEIL, IAR and others). STM32CubeProgrammer is an independent tool for programming internal or external memory via JTAG or bootloader interfaces. STM32CubeMonitor is a useful tool to support debugging, it allows to display the power consumption of the microcontroller.

Ecosystem includes also the STM32CubeU5 library package and consistent set of middleware components (Azure RTOS USBX, FileX/LevelX,ThreadX, NetX Duo, USB Power Delivery, TF-M, mbed-crypto, Touch library, Network library and OpenBootloader). All embedded software utilities are delivered with a full set of examples running on STMicroelectronics boards.

The STM32Cube libraries consist of two types – a Hardware Abstraction Layer (HAL) library providing APIs (Application Programming Interfaces) for interacting with the microcontroller peripherals, and a Low-Layer (LL) library referring to the hardware-oriented functions provided by the STM32. The HAL and LL libraries can be used simultaneously with few restrictions STM32CubeU5 gathers in one single package all the generic embedded software components required to develop an applications on STM32U5 microcontrollers. Following STM32Cube initiative, this set of components is highly portable to other STM32 Series. HAL and LL APIs are available in open-source BSD license for user convenience.

STM32U5 devices support Arm® PSA security model. A Trusted Firmware M (TF-M) reference code is provided within STM32Cube to implement the following security functions: Secure Boot, Secure Firmware Update, secure storage, resource isolation, secure execution, cryptographic engine and software IP protection.

The STM32Cube ecosystem has been complemented by the Microsoft Azure RTOS, making it easier and faster to design and develop smart devices, including IoT applications. Azure RTOS allows for the delivery of ready-to-use services that enable application management. All licenses for Microsoft Azure RTOS are available free of charge for STM32 microcontroller.


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