STMicroelectronics and the 32-bit

STMicroelectronics and the 32-bit STM32 microcontroller family

STMicroelectronics is one of the world’s largest semiconductor companies and is a major vendor of microcontrollers for embedded application development. The company’s industry-leading STM32 family of 32‑bit Flash microcontrollers are based on the ARM Cortex™-M series of processor cores – including the Cortex-M0, Cortex-M0+, Cortex-M3 and Cortex-M4 – and combines high performance, real-time and digital signal processing (DSP) capabilities, together with low power and low voltage operation and an extensive choice of on-chip peripherals.

Accompanied by a wide choice of starter kits, development boards, tools and software, the STM32 family is an extensive portfolio of more than 400 MCUs ranging from entry level and ultra low power devices that can deliver 26 DMIPS at 32MHz to mid range mainstream MCUs offering 61 DMIPs at 72MHz, all the way up to high performance devices with DSP and floating point capabilities that deliver 225DMIPS at 180MHz.


The STM32 portfolio of 32-bit microcontrollers is based on the ARM Cortex-M series of processor cores


Key Cortex-M based series within the STM32 family include:

The STM32 F0 series of entry-level Cortex-M0 based MCUs is well suited to cost-sensitive applications and combine real time performance, low power operation and the advanced architecture and peripherals associated with the STM32 platform.

The STM32 F1 series of mainstream Cortex-M3 based MCUs covers the needs of a wide variety of applications in the industrial, medical and consumer markets. High performance with first class peripherals and low power, low voltage operation is paired with a high level of integration at accessible prices with a simple architecture and easy-to-use tools. Pin-to-pin, peripheral and software compatible, the series consists of five product lines, including the STM32F100 Value Line, which features a 24MHz CPU and is ideal for motor-control applications.

The STM32 F2 series of high-performance Cortex-M3 based MCUs uses ST’s 90nm non-volatile memory (NVM) process technology with adaptive real-time (ART) memory accelerator and multi-layer bus matrix, which offers an unprecedented trade-off in price and performance. The series is highly integrated and combines up to 1 Mbyte of Flash memory and up to 128 Kbytes of SRAM, along with Ethernet MAC, USB 2.0 HS OTG, camera interface, hardware encryption support and external memory interface. The acceleration technology enables the MCUs to achieve up to 150 DMIPS at 120MHz, which is equivalent to zero-wait-state execution, while also keeping dynamic current consumption as low as 175µA/MHz.

The STM32 F3 series of mixed-signal Cortex-M4 based MCUs combines a 32-bit Cortex-M4 running at 72MHz with DSP and floating-point unit (FPU), together with a high number of integrated analog peripherals leading to simplified and cost-reduced application design.

The series offers devices with memory capacities ranging from to 32 up to 256 Kbytes of Flash and includes product lines such as the STM32F302 MCU for general-purpose applications, the STM32F303, which is aimed at motor-control applications, and the STM32F373, which integrates a 16-bit sigma-delta ADC for high-precision measurement applications such as biometric sensors or smart metering.

The STM32 F4 series of Cortex-M4 based MCUs is the highest performance STM32 series. Delivering real-time control capabilities of an MCU and the signal processing performance of a DSP, the series leverages ST’s NVM technology and ART accelerator to reach the industry’s highest benchmark scores for Cortex-M-based microcontrollers with up to 225 DMIPS executing from Flash memory at up to 180MHz. The series also implements dynamic power scaling and consists of five compatible product lines.

These include the STM32F401, the most cost-effective series offering a 105 DMIPS CPU at 84MHz; the STM32F407, which offers a 210 DMIPS CPU at 168MHz, with up to 1 Mbyte of Flash, plus Ethernet MAC and camera interface; and the STM32F429, a 225 DMIPS CPU at 180MHz, with up to 2 Mbytes of dual-bank flash, in addition to an LCD-TFT controller.

The STM32 L1 series of ultra-low-power Cortex-M3 based MCUs uses proprietary ultra-low leakage process technology with autonomous dynamic voltage scaling and five low power modes including a low power run mode at only 9μA consumption and a dynamic run mode as low as 177μA/MHz. The series also offers a wide portfolio of features such as hardware encryption, and a wide range of memory sizes, package pin counts and peripherals such as USB, LCD interface, comparators, ADC and DAC. The portfolio covers from 32 to 512 Kbytes of Flash memory (with up to 80 Kbytes of SDRAM and 16 Kbytes of true embedded EEPROM) and from 48 to 144 pins. The series includes four product lines including the entry-level STM32L100 value line.

The STM32W series of wireless MCUs combines the ARM Cortex-M3 processor with a 2.4GHz IEEE 802.15.4 radio in a low power architecture and is aimed squarely at the wireless sensor network market. The series offers best-in-class code density and is an open platform with extra resources for application integration including configurable I/O, ADC, timers, SPI and UART interfaces. Also included are RF4CE and IEEE 802.15.4 MAC software libraries. The series features devices with 64 to 256 Kbytes of on-chip Flash memory and up to 16 Kbytes of SRAM.


Development Kits and Boards

A wide range of starter and development kits, boards and tools is available for STM32-based application development, including the brand new Nucleo development boards.

Basic family starter and evaluation kits for the STM32 platform include the Raisonance STM32 Cortex starter kit, Raisonance STM32 Primer, STM32-Performance evaluation stick, STM32-comStick (STM32F107VC microcontroller) and the Starter Kit (IAR™) for STM32 Cortex. Development kits specific to individual STM32 series come in the form of ST’s Discovery Kits, which include kits for the STM32F0, STM32F1, STM32F3 and STM32F4 series.

The STM32F3 Discovery Kit

Also available are the STM32F429I STM32F4 series and the STM32F401C STM32F4 series Discovery Kits for high-performance application development based on Cortex-M4 STM32 MCUs, and a duo of evaluation boards for STM32F3-based development: the STM32F3 series evaluation board (STM32F373 MCU) for data acquisition and the STM32F3 series evaluation board (STM32F303 MCU).

Latest additions to the STM32 development environment are the STM32 Nucleo Development Boards. These new boards have two major features that should attract attention among engineers: mbed compatibility, allowing developers to make use of the mbed open-source software platform, online C/C++ SDK (Software Development Kit) and collaboration infrastructure at; and Arduino connectivity via headers that accept shields from the extensive Arduino ecosystem. The STM32 Nucleo boards come with an integrated ST-Link debugger/programmer and work with a wide range of software development environments including IAR EWARM, Keil MDK, mbed, GCC-based IDEs (Atollic TrueStudio). Specific Nucleo development boards are available for the respective STM32 F0, STM32 F1, STM32 F4 and STM32 L1 series.


Software Tools

The STM32 family is supported by a wide range of software tools including traditional IDEs (Integrated Development Environments) with C/C++ compilers and debuggers from major third-party vendors, with free versions available for up to 64KB of code. Also available are ST tools that enable MCU configuration, initialization and behavioural monitoring during run time. In particular, and available free-of-charge, is STM32Cube™, which is designed to reduce development time and costs for STM32-based application development. STM32Cube includes the STM32CubeMX graphical software configuration tool, which enables the generation of C initialisation code using graphical wizards and also embeds a comprehensive software platform – available per series, such as the STM32CubeF4 for the STM32F4 series. This platform includes the STM32Cube HAL, which is an embedded software abstraction layer that ensures maximised portability across the STM32 portfolio, in addition to offering a consistent set of middleware components including RTOS, USB, TCP/IP and graphics.