STM32 F4 Series Cortex™-M4 MCUs

Introduction to the STM32 F4 Series

The STM32 F4 series is STMicroelectronics' extension into the digital signal controller (DSC) market, based on the ARM® Cortex™-M4 core. These devices offer enhanced performance, DSP capabilities, a floating-point unit (FPU), increased SRAM, and advanced peripherals compared to the STM32 F2 series, while maintaining pin-to-pin and software compatibility. Key improvements include a TFT LCD controller with graphics acceleration, SDRAM support, a serial audio interface, ultra-low power consumption for the Real-Time Clock (RTC) (less than 1 µA), and fast 2.4 MSPS ADCs. The ARM® Cortex™-M4 core features built-in single-cycle multiply-accumulate (MAC) instructions, optimized SIMD, and saturated arithmetic instructions.

The adaptive real-time ART Accelerator™, combined with ST's 90 nm technology, enables linear performance up to 180 MHz (225 DMIPS). The Chrom-ART Accelerator™ doubles performance for graphics content creation and handling. The STM32 F4 series balances performance (up to 105 DMIPS) with low power consumption, achieving as low as 128 µA/MHz in Run mode and typically 9 µA in Stop mode. High integration is achieved with packages as small as 3 x 3 mm. Devices offer up to 2 Mbytes of on-chip Flash memory, up to 256 Kbytes of SRAM, and 20 communication interfaces. Available packages include WLCSP (down to 3 x 3mm), UFQFPN48, LQFP64, LQFP100, LQFP144, LQFP176, UFBGA100, UFBGA169, UFBGA176, LQFP208, and TFBGA64/TFBGA216.

Key Applications

• Industrial and medical equipment
• Control panels with LCD screens for alarm systems, high-end meters, factory automation
• Medical devices: respiratory equipment, patient monitors
• EPOS systems: scanners, cash registers, tax machines, vending machines, printers
• Industrial AC servos, general-purpose inverters, solar inverters, and robots
• Surveillance cameras
• Consumer electronics: HMI for appliances, DAB car radios, infotainment systems, home audio, switch boxes, headsets
• Sensor hubs for mobile devices

Block Diagram Overview

The block diagram illustrates the core components of the STM32 F4 series MCUs. At the center is the ARM Cortex-M4 core operating at up to 180 MHz, featuring a Floating Point Unit (FPU) and Nested Vector Interrupt Controller (NVIC). The ART Accelerator™ enhances performance by providing zero-wait execution from Flash. The system includes power management (1.2 V regulator, POR/PDR/PVD), clock control (oscillators, PLL), timers (SysTick, watchdogs), and I/O capabilities. A Multi-AHB bus matrix and 16-channel DMA controller manage data transfers. Specialized processors include a Crypto/hash processor (supporting 3DES, AES 256, GCM, CCM, SHA-1, SHA-256, MD5, HMAC) and a True Random Number Generator (RNG). Connectivity features include a Camera interface, Ethernet MAC with IEEE 1588 support, multiple USB 2.0 OTG interfaces (FS/HS), SDIO, numerous USART/UART ports (with LIN, smartcard, IrDA support), and a Serial Audio Interface (SAI). The analog subsystem comprises 2x 12-bit DACs, 3x 12-bit ADCs (up to 2 MSPS), and a temperature sensor. Control peripherals include 2x 16-bit motor control PWM timers, synchronized AC timers, and multiple general-purpose timers.

Features and Benefits

High Performance

• Features: Up to 180 MHz/225 DMIPS Cortex-M4 core with single-cycle DSP MAC and FPU. CoreMark score of 608 at 180 MHz (3.37 CoreMark/MHz).
• Benefits: Boosted execution of control algorithms, enabling more complex features. Improved code efficiency and faster time-to-market. Elimination of scaling and saturation issues. Easier support for meta-language tools.

Maximum Integration

• Features: Up to 2 Mbytes of on-chip dual-bank Flash memory, up to 256 Kbytes of SRAM, reset circuit, internal RC oscillators, PLLs, and ultra-small packages (WLCSP).
• Benefits: Supports read-while-write operations. Enables more features in space-constrained applications. Facilitates the use of high-level languages like Java and .Net.

Designed for High Performance and Ultra-Fast Data Transfers

• Features: ART Accelerator™ memory accelerator, Chrom-ART Accelerator™ for graphics (rectangle filling, copy, pixel format conversion), 32-bit, 7-layer AHB bus matrix (up to 10 masters, 8 slaves), Multi-DMA controllers, dedicated SRAM block for the core, flexible memory interface with SDRAM support (up to 90 MHz, 32-bit parallel).
• Benefits: Performance equivalent to zero-wait execution from Flash. Graphics content created twice as fast and independently from the CPU. Concurrent execution and data transfer. Simplified resource allocation, high bandwidth for external memories, and cost-effective external RAM.

Outstanding Power Efficiency

• Features: Ultra-low dynamic power in Run mode (128 µA/MHz at 84 MHz for STM32F401, 260 µA/MHz at 180 MHz for STM32F429/439). RTC current <1 µA in VBAT mode. Low Stop mode current (down to 9 µA typ for STM32F401, 100 µA typ for STM32F429/439). Operates from 1.7 V to 3.6 V with a 1.2 V voltage regulator and power scaling.
• Benefits: Extra flexibility to reduce power consumption for applications requiring high processing and low-power performance, especially when running on battery power.

Superior and Innovative Peripherals and Connectivity

• Features: Camera interface, crypto/hash HW processor (AES GCM/CCM, SHA-256), Ethernet MAC (10/100, IEEE 1588 v2), 2x USB OTG (one with HS), up to 20 communication interfaces (including USART, UART, SPI, I2C, CAN, SDIO), audio interfaces (I2S, SAI with TDM), LCD TFT controller (up to XGA, 24-bit RGB parallel pixel output, 2-layer blending), 2x 12-bit DACs, 3x 12-bit ADCs (up to 7.2 MSPS interleaved), up to 17 timers (16/32-bit up to 180 MHz).
• Benefits: New possibilities for high-speed data communication. High-quality multi-channel audio support. Support for cost-effective standard displays. High resolution and precision in analog measurements.

High Integration

• Features: Available in ultra-small packages like WLCSP49 (3 x 3 mm), WLCSP90 (4 x 4.2 mm), and WLCSP143 (4.5 x 5.5 mm).
• Benefits: Enables smaller board designs for more portable applications.

Extensive Tools and Software Solutions

• Features: Hardware sector protection for execute-only access. Wide range of IDEs, starter kits, libraries, RTOS, and stacks (open-source and third-party), including the ARM CMSIS DSP library.
• Benefits: Provides robust software IP protection. Offers a wide choice within the STM32 ecosystem for application development.

ART Accelerator Performance and Dynamic Efficiency

The ART Accelerator™, combined with ST's 90 nm technology, enables linear performance up to 180 MHz, delivering 225 DMIPS and 608 CoreMark performance when executing from Flash. This is achieved through a prefetch queue, branch cache, and smart arbitration. MCUs without such accelerators may suffer from performance impacts due to wait states or higher power consumption from frequent Flash accesses.

The STM32 Dynamic Efficiency™ principle, applied to the STM32F401, ensures low dynamic power consumption. With the ART Accelerator™, performance reaches 105 DMIPS (285 CoreMark) at 84 MHz, with RUN currents as low as 128 µA/MHz. The 90nm process technology boosts performance and reduces dynamic power. Dynamic voltage scaling optimizes operating voltage to meet performance demands and minimize leakage. Stop mode current is typically only 9 µA at 1.8V.

Current Consumption Examples (Typical, Room Temperature):

• Dynamic Run Mode:
• 244 µA/MHz @ 180 MHz (44 mA total)
• 238 µA/MHz @ 168 MHz (40 mA total)
• 128 µA/MHz @ 60 MHz
• 137 µA/MHz @ 84 MHz
• Stop Mode:
• 280 µA (Wake-up time: 110 µs)
• 120 µA (Wake-up time: 105 µs)
• 9 µA (Wake-up time: 113 µs)
• 41 µA (Wake-up time: 21 µs)
• Standby Mode (w/o and w/ RTC): 2.2 µA to 3.1 µA (Wake-up times vary: 375 µs, 318 µs)
• VBAT Mode (w/o or w/ RTC): <1 µA

Note: Run mode conditions: CoreMark executed from Flash, peripherals off.

Richer Graphics and Human Machine Interface

The ST Chrom-ART™ Accelerator efficiently handles repetitive graphics operations like raw data copies, image blending, and pixel format conversion, operating independently from the CPU for increased efficiency. STM32F429 MCUs integrate an LCD-TFT controller and support external memory interfaces (static and SDRAM), enabling high-throughput graphics for resolutions up to XGA (1024 x 768) at up to 20 frames/s, while freeing up the CPU for real-time tasks.

Human Machine Interface Implementation Example:

An example setup for STM32F427/429 MCUs using the Chrom-ART Accelerator involves an internal or external memory for the frame buffer and a TFT controller for display. This can support resolutions up to XGA (1024 x 768) using a 16-/32-bit external memory interface. Recommended packages include LQFP100, LQFP144, LQFP176/BGA176, or LQFP208/BGA216. The system architecture includes the Cortex-M4 core, Chrom-ART Accelerator, TFT Controller, and a Bus Matrix. It connects to a dedicated TFT interface with programmable timings or directly to an LCD TFT display or chip-on-glass display via a parallel interface. Memory interfaces support up to 2 Mbytes of internal Flash and 256 Kbytes of internal SRAM, with external memory controllers supporting Flash, SRAM, and SDRAM.

High Integration and Sensor Hub Capabilities

Consumer and industrial applications increasingly demand smaller form factors for portability. ST's 90 nm process and design strategies allow the STM32 F4 series to be available in packages as small as 3 x 3 mm, packed with rich connectivity and features.

STM32F401 as a Sensor Hub: The STM32F401 is well-suited as a sensor hub for medical, industrial, and consumer applications. It integrates sensors like G sensors, gyroscopes, and compasses, communicating via I2C (1 Mbit/s). It also includes a 12-bit ADC for pressure and ambient light sensors, and can interface with a main processor (1.8 V) and application processor via SPI (42 Mbit/s) or USB OTG FS.

Hardware Tools

A comprehensive suite of hardware tools is available to leverage the STM32 F4's features.

Discovery Kits

User-friendly and affordable demo boards offering specific companion devices (MEMS microphones, LCD displays, MEMS sensors) and software examples. All include the ST-LINK/V2 in-circuit debugger/programmer. Associated expansion boards add capabilities like Ethernet, Wi-Fi, and CMOS cameras. Examples include STM32F429I-DISCO, STM32F401C-DISCO, and STM32F4-DISCOVERY.

Evaluation Boards

Premium development platforms with full device peripheral implementation. Available in various form factors with extensive resources like up to 2-Mbyte Flash, 32-Mbyte SDRAM, and 5.7-inch LCD displays. They include an ST-LINK/V2 debugger/programmer and a free software library. Examples include STM3241G-EVAL, STM32429I-EVAL1, and STM32439I-EVAL2.

Nucleo Boards

Open platforms offering unified extension capability at budget costs. They feature Arduino™ connectivity and full peripheral access, making it easy to expand functionality with specialized shields. The STM32F401 Nucleo is mbed-enabled, providing instant access to an online IDE. Example: NUCLEO-F401RE.

Partner Solutions

Complementary solutions from ST partners include IAR Experiment! kits, Keil Starter kits, Raisonance EvoPrimer platform, STM32F4 Java evaluation kits (IS2T), and the Mountaineer Microsoft .NET Micro Framework platform.

Additional expansion boards are available, such as those adding Ethernet, Wi-Fi, and CMOS cameras.

Software Solutions

STM32 F4 microcontrollers can be programmed using C/C++, Java, or Matlab/Simulink. ST's partners provide a wide range of software tools and embedded solutions.

C/C++ Development

Supported by various Integrated Development Environments (IDEs) from partners, including project managers, editors, debuggers, optimizing compilers, flash loaders, and example projects. Embedded software libraries from partners like Alpwise (Bluetooth), FreeRTOS (RTOS), Micrium (µC/TCP-IP), Express Logic (TheadX), and HCC (USB libraries) are available.

Beyond C/C++ Development

STM32 Java Development Environment: An Eclipse-based environment with a simulator, Java Virtual Machine, and mechanisms to call legacy C code. It allows GUI development leveraging Chrom-ART acceleration.

.NET Micro Framework: Enables development using Microsoft Visual Studio.

Matlab/Simulink Integration: Allows peripheral modelization and code generation for Cortex-M DSP libraries.

STM32 Cube Ecosystem

STM32CubeMX: A PC tool that simplifies microcontroller configuration through wizards, generating initialization C code and project files for various development environments.

STM32CubeF4: A set of generic software bricks for the STM32 F4, ensuring portability across STM32 series. It includes full peripheral coverage, production-ready drivers, middleware (USB, TCP/IP, graphics, RTOS, file system), and hundreds of examples. The driver layer is open-source.

Application-Specific Bricks

STM32 Audio Solutions: Optimized software bricks for audio processing, including transport layers, music/speech codecs (MP3, WMA, AAC, Speex, G726, etc.), and post-processing algorithms (sample rate converters, equalizers, stereo widening).

Smartphone Accessory Libraries: Support for protocols like iAP (iPod Application Protocol) and Android interfacing.

STM32 Industrial Protocols: Support for industrial protocols such as Profinet, EtherCAT, Modbus, DeviceNet, and CANopen, leveraging the IEEE 1588 feature.

STM32 Cryptographic Library: Implements cryptographic algorithms using hardware acceleration where available or software implementation.

STM32 F4 Product Lines

The STM32 F4 series offers several product lines, each built around the Cortex™-M4 core with DSP and FPU, and sharing common features like USB 2.0 OTG, SDIO, USART, SPI, I2C, I2S audio, PLL, and 16/32-bit timers. Key differentiators include clock speed, Flash and SRAM sizes, and the presence of specific peripherals like Crypto/hash, RNG, DAC, Ethernet with IEEE 1588, CAN, Camera Interface, SDRAM interface (FMC), Serial Audio Interface (SAI), Chrom-ART Accelerator, and TFT LCD Controller.

Key Product Lines:

• STM32F429/439: 180 MHz, 512 KB to 2 MB Flash, 256 KB SRAM. Includes Crypto/hash, RNG, DAC, Ethernet, IEEE 1588, CAN, Camera I/F, SDRAM, FMC, SAI, Chrom-ART Accelerator, TFT LCD Controller.
• STM32F427/437: 180 MHz, 1 to 2 MB Flash, 256 KB SRAM. Includes Crypto/hash, RNG, DAC, Ethernet, IEEE 1588, CAN, Camera I/F, SDRAM, FMC, SAI, Chrom-ART Accelerator.
• STM32F407/417: 168 MHz, 512 KB to 1 MB Flash, 192 KB SRAM. Includes Crypto/hash, RNG, DAC, Ethernet, IEEE 1588, CAN, Camera I/F, SDRAM, FMC, SAI.
• STM32F405/415: 168 MHz, 512 KB to 1 MB Flash, 192 KB SRAM. Includes Crypto/hash, RNG, DAC, Ethernet, IEEE 1588, CAN, Camera I/F.
• STM32F401: 84 MHz, 128 KB to 512 KB Flash, 96 KB SRAM. Features STM32 Dynamic Efficiency™ with low Run and Stop mode currents, and small form factor (down to 3 x 3 mm).

Note: Specific features like hardware crypto/hash are available on certain sub-series (e.g., F415/417, F437/439).

STM32 F4 Portfolio Overview

The STM32 F4 portfolio is extensive, offering a wide range of Flash sizes and pin counts to meet diverse application needs. The portfolio spans from 128 KB Flash devices in 48/49-pin packages up to 2 MB Flash devices in 216-pin packages. Models like the STM32F401 series are available in smaller Flash sizes (128 KB to 512 KB) and fewer pins (48-64 pins), while higher-end series like STM32F429/439 and STM32F437/439 offer up to 2 MB Flash and are available in packages with up to 216 pins.

Device Summary

The following tables provide a detailed specification summary for the STM32 F4 series MCUs, covering key parameters such as Flash size, internal RAM, package type, timer functions, I/O count, serial interfaces, supply voltage, and power consumption in lowest power and run modes.

Notes: Operating temperature: -40 to 85 °C for WLCSP packages and -40 to 105 °C for all other packages. HS requires an external PHY connected to the ULPI interface. Crypto/hash processor is available on STM32F417, STM32F415, STM32F437, STM32F439. 1.7 V operation requires external reset circuitry and is limited to the 0 to 70 °C temperature range. Marked values like (3+2) indicate multiple USART/UART ports. Availability of some models was noted as July 2014.