The STM32F407 is an ARM Cortex-M4 core-based high-performance microcontroller developed by STMicroelectronics. It offers advanced processing capabilities, high-speed connectivity, and rich peripherals while maintaining low power consumption.
Overview
The STM32F407 is based on the high-performance ARM Cortex-M4 32-bit RISC core which can run up to 168MHz. It has 1MB of flash memory and 192KB of SRAM. The chip provides extensive connectivity options including Ethernet, USB OTG, CAN, SDIO, SPI, and I2C. The STM32F407 also includes a rich set of peripherals such as ADCs, DACs, timers, real-time clock, and multiple communication interfaces.
Key Features
- ARM Cortex-M4 core: Offers DSP instructions and floating point unit, running up to 168MHz.
- Memory: 1MB flash memory, 192KB SRAM, 4KB battery-backed SRAM.
- Clock management: Internal oscillators, phase-locked loops, multiple clock outputs.
- Power modes: Sleep, stop, standby modes for low-power operation.
- Connectivity: USB 2.0 OTG HS and FS, Ethernet MAC, 2xCAN, SDIO, SPI, I2C.
- Peripherals: Up to 3xADC, 2xDAC, 2xoperational amplifiers, timers, real-time clock, watchdog.
- Debugging: SWD, JTAG interfaces for programming and debugging.
- PWM support: Advanced timers for motor control and advanced lighting applications.
- Package options: LQFP100, LQFP144, LQFP176, UFQFPN48.
ARM Cortex-M4 Core
The STM32F407 incorporates ARM’s Cortex-M4 core, which includes DSP instructions and a floating point unit. It delivers exceptional performance and power efficiency. The Cortex-M4 CPU can reach frequencies up to 168MHz. It has a 3-stage pipeline, uses Harvard architecture with separate instruction and data buses, and featuresThumb-2 instruction set for optimal code density.
The DSP capability allows efficient processing of signal processing algorithms for applications like audio processing, sound synthesis, encryption, image processing etc. The FPU enables floating point calculations to be performed efficiently. Overall, the Cortex-M4 core provides high performance signal processing capabilities to the STM32F407 MCU.
Memory
The STM32F407 microcontroller contains 1MB of flash memory for storing code and data. It provides 192KB of SRAM for data storage and processing. Additionally, it has 4KB of battery-backed SRAM which can preserve data when main power is lost. The SRAM supports 32-bit word access for higher performance.
The flash memory supports read-while-write operation, allowing code execution to continue uninterrupted during flash write or erase. The STM32F407 memory architecture is optimized for high performance and low power consumption during operation.
Clock Management
The STM32F407 includes advanced clock management and generation capabilities. It integrates multiple internal oscillators including a high-speed (HS) oscillator, two low-speed (LS) oscillators and three low-power (LP) oscillators. There are three phase-locked loops (PLLs) to generate clock frequencies for various functional blocks.
The clock tree allows selection of clock source, dividers, and multipliers to generate system, peripheral, AHB, and APB clocks. Various peripheral clocks can be gated on/off for reduced power consumption when not in use. Multiple dedicated clock outputs are available.
Low Power Operation
The STM32F407 MCU provides various power saving modes for low power applications:
- Sleep mode: CPU stopped, peripherals and SRAM remain active.
- Stop mode: All clocks gated, SRAM and registers retain state, fast wakeup.
- Standby mode: VBAT domain remains powered, backup SRAM retained.
- Low-power run mode: Lowest current in run mode.
In sleep mode, the CPU stops but SRAM and peripherals remain functional. Stop mode turns off clocks and halts CPU/peripherals while retaining register contents. Standby mode keeps the VBAT domain powered to retain backup SRAM and RTC operation. Advanced voltage scaling reduces power in run mode.
Connectivity
The STM32F407 provides extensive connectivity options through its rich set of peripherals:
- USB 2.0 OTG HS and FS: Supports USB host and device functionality.
- Ethernet MAC: 10/100 Mbps with MII/RMII interface.
- 2xCAN: Two CAN controllers supporting CAN 2.0B.
- SDIO: Secure digital input/output support.
- SPI: Up to 3 SPI controllers supporting full-duplex synchronous serial communication.
- I2C: Support for standard mode, fast mode and SMBus modes.
This allows interfacing with a wide range of peripherals and networking hardware for building connected applications.
Analog peripherals
The STM32F407 contains a rich set of analog peripherals, including:
- Up to 3×12-bit ADCs, with 16 channels each for a total of 48 channels.
- 2×12-bit DACs.
- 2xoperational amplifiers.
- 21x analog comparators.
These enable analog signal acquisition, conversion and processing for sensor measurement, motor control, audio processing, and other analog-interface applications.
Timers
Advanced control-oriented timer peripherals on the STM32F407 MCU include:
- 6x general purpose 16/32-bit timers with capture/compare channels.
- 2x advanced timers for motor control and power conversion applications.
- 2x watchdog timers.
- SysTick timer for RTOS use.
- Low-power timer for real-time clock.
These allow generation of time-bases, input captures, output waveforms, counters, interrupts, synchronization and other timer functionality for control applications.
Debugging
For programming and debugging the STM32F407, debug modes like Serial Wire Debug (SWD) and Joint Test Action Group (JTAG) are supported. The chip integrates a Serial Wire Viewer for analyzing data on the fly. Cortex debug and ETM trace allow more control over code execution.
Motor Control
The STM32F407 includes advanced control peripherals suitable for 3-phase motor control applications:
- Advanced timers for PWM generation and quadrature encoding input.
- 12-bit ADCs and DACs.
- Operational amplifiers for current sensing.
- Comparators for zero-crossing detection.
This enables advanced motor control techniques like field-oriented control (FOC), sensored and sensorless control algorithms for motors in industrial, automotive, consumer appliance applications.
Package Options
The STM32F407 is available in a range of package options with different pin counts:
- LQFP100: Low-profile quad flat package, 100 pin.
- LQFP144: LQFP, 144 pin.
- LQFP176: LQFP, 176 pin.
- UFQFPN48: Ultra-thin quad flat package, no leads, 48 pin.
This provides flexibility in selecting the right package for the application based on I/O requirements, PCB constraints, thermal considerations, and cost.
Conclusion
The STM32F407 integrates ARM Cortex-M4 core with floating point unit and DSP instructions, extensive memory and connectivity peripherals, advanced timers and motor control capabilities, in low-power and cost-effective packages. It provides a high-performance, feature-rich MCU solution suitable for a wide range of embedded applications.
