STMicroelectronics' new STM32 F427 and F437 MCUs

Designers of smart, connected embedded electronics for applications such as utility metering, renewable energy, and healthcare, have begun adopting new class-leading microcontrollers from STMicroelectronics.

The STM32 F427 and F437 microcontrollers extend the existing STM32 F4 portfolio by combining the highest-performing version of the ARM Cortex-M4 core with the industry’s largest Flash memory storage and extra SRAM for running richer applications, extra communication ports, enhanced security, and best-in-class power consumption. These features help speed up software design, enhance application performance, and maximize battery life.

“Sophisticated features and connectivity of our newest STM32 microcontrollers bring exceptional user experiences to everyday electronic products,” said Michel Buffa, General Manager, Microcontroller Division, STMicroelectronics. “We are already working with lead customers to design the extended STM32 F4 variants, which provide up to 2 Mbytes of Flash memory, into applications such as smart meters, solar panel controllers, wireless modules, and personal medical monitors.”

With large on-chip Flash memory of 1 MByte or 2 Mbytes, the extended STM32 F4 devices enable developers to create more feature-rich applications and accelerate project completion by programming with high-level languages such as Java, Microsoft .Net or uClinux. Using high-level languages also allows embedded-system developers to take advantage of software advances for desktop applications. All of the extended 1 MByte and 2 MByte variants have 256 KByte SRAM, allowing designs using current devices with 1 MByte Flash and up to 192 Kbyte SRAM to move easily onto a microcontroller with higher SRAM if required.


The STM32 F437 series provides enhanced security to protect the product developer’s intellectual property (IP) and end-user data against unauthorized access or tampering. With additional industry-standard security algorithms now included in the cryptographic and hash co-processor, these devices support MD5, SHA-1 and SHA-2 secure hash algorithms, AES GCM (Advanced Encryption Standard Galois/Counter Mode), and CCM (Combined Cipher Machine).

Further information
The Cortex-M4 processor of the STM32 F427 and F437 comprises a 32-bit microcontroller, floating-point arithmetic unit and Digital Signal Processor (DSP). Aided by ST’s multi-AHB bus matrix, which enhances CPU and DMA (Direct Memory Access) controller bandwidth, and Adaptive Real-Time (ART) accelerator, which allows zero-wait execution from Flash, it achieves performance of 210 DMIPS (566 CoreMark) at 168 MHz. This is the maximum performance a Cortex-M4 core can deliver at this frequency.

Adding versions with 1 MByte or 2 MByte of on-chip Flash, all with 256 Kbyte of SRAM represents a significant expansion of integrated memory resources compared to other Cortex-M4 microcontrollers in the market. This allows developers to manage the large quantities of code and data associated with richer applications without adding expensive external Flash and SRAM (taking advantage of the external memory interface of the STM32 F4 series) or using ROM-less architecture. A ROM-less solution can be even more expensive, and can significantly increase pc-board complexity and electromagnetic emissions.

For applications requiring enhanced connectivity the STM32 F427 and F437 provide four USARTs and four UARTs, compared with four USARTs and two UARTs in existing STM32 F2 and F4 devices. Also integrated on-chip are six SPI ports, increased from three SPI ports on the F2 and F4 series, and optional digital filtering for the three I2C interfaces to promote robust communications.

A total of 16 new STM32 F427 and F437 variants join the existing STM32 F407 and F417 series announced in September 2011. Overall, ST’s STM32 family now comprises more than 360 separate part numbers spanning ARM Cortex-M0, M3 and M4 cores, with on-chip Flash from 16 KB to 2 MB, up to 256 KB SRAM, and package options from 36 pins to 176 pins.

The new STM32 F427 and F437 variants present a straightforward pin-to-pin and software-compatible upgrade path offering extra resources to enhance applications based on existing STM32 F2 and STM32 F4 devices. In addition, with larger on-chip memory and the DSP-enhanced Cortex-M4 core, the latest devices provide a highly integrated alternative for systems using a microcontroller and separate DSP, also leveraging the extensive STM32 development ecosystem.

Additional key features of STM32 F427/37

• 4 KB + 80 Byte backup SRAM
• Communication interfaces: 4x USART, 4x UART, 6x SPI, 3x I2C with digital filters, 2x CAN, SDIO, 2x USB OTG
• Dedicated audio PLL and two full-duplex I2S channels
• Ethernet 10/100 MAC with IEEE 1588 v2 support
• 2x 12-bit DAC, 3x 12-bit ADC, up to 17 16/32-bit timers

Availability and pricing
STM32 F427 and F437 microcontrollers are sampling now to lead customers, and will enter full production during Q1 2013 in LQFP100, LQFP144, LQFP176 and UFBGA176 packages. ST has released the following prices for 1 MByte and 2 MByte variants:

The STM32F427VGT6 with 1MB Flash, 256KB SRAM in LQFP100 package has a resale price at $7.45 of 1,000 units/year.

The STM32F437IIH6 with 2MB Flash, 256KB RAM, Crypto/Hash processor in UFBGA176 package has a resale price at $9.50 of 1,000 units/year.

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