ST adds Cortex-M4 devices to STM32 portfolio

Colin Holland, EE Times -- EDN, October 20, 2011

STMicroelectronics based its new STM32 F4 series of microcontrollers on the ARM Cortex-M4 core, which adds signal-processing capabilities and faster operations. The STM32 F4 series extends the STM32 portfolio and has more than 250 compatible devices in production, including the F1 series, the F2 series, and the ultra-low-power L1 series. The company is widening its target applications with the STM32 F4 series. Its single-cycle DSP instructions should provide access to the DSC (digital-signal- controller) market, which requires high computational capability and DSP instructions for applications such as high-end motor control, medical equipment, and security.


The F4 series provides ultrafast data transfers, with a sevenlayer, multiple-AHB (advanced high-performance-bus) matrix and multiple DMA (direct-memory-access) controllers, which allow concurrent execution and data transfers. The integrated single-precision FPU boosts the execution of control algorithms, improves code efficiency, eliminates scaling and saturation, and allows the use of metalanguage tools.

The device integrates a reset circuit, PLLs (phase-locked loops), and a less-than-1-μA real-time clock with less-than- 1-sec accuracy. It has 4 kbytes of backup SRAM to save data in standby or battery-backup mode. Typical real-time-clock power consumption is less than 1 μA in battery-voltage mode, and an internal voltage regulator with power scaling enables the trade-off of performance versus power consumption.

Connectivity includes a camera interface; a cryptography/ hash-encryption hardware processor; a 10- and 100-GbE (gigabit-Ethernet) MAC (mediaaccess controller) with IEEE 1588 Version 2 support; and two USB (Universal Serial Bus) OTG (On-The-Go) ports, one of which has HS (high-speed) support.

The device includes a dedicated audio PLL and two fullduplex I²S (inter-integrated-circuit-sound) ports. It also has as many as 15 communication interfaces, including six USARTs (universal synchronous/ asynchronous receivers/ transmitters) operating as fast as 10.5 Mbps, three SPIs (serial-peripheral interfaces) operating as fast as 42 Mbps, three I²C (inter-integrated-circuit) ports, two CAN (controller-area-network) interfaces, and one SDIO (serialdigital input/output) interface. The analog circuits include two 12-bit DACs; three 12-bit ADCs with rates as high as 2.4M or 7.2M samples/sec in interleaved mode; and as many as 17 timers, including 16- and 32-bit devices operating as fast as 168 MHz.

Four variants are available. The STM32F405x has timers, three ADCs, two DACs, serial interfaces, an external memory interface, a real-time clock, a CRC (cyclic-redundancy-check)-calculation unit, and an analog true-randomnumber generator, as well as a USB OTG FS (full-speed)/HS interface. It is available in WLCSP64, LQFP64, LQFP100, and LQFP144 packages with 1 Mbyte of flash.

STM32F407 products add a second FS-only USB OTG interface; an integrated 10- and 100-GbE MAC supporting both an MII (media-independent interface) and an RMII (reducedmedia- independent interface), with IEEE-1588 precise-time protocol Version 2 hardware support and an 8- to 14-bit parallel camera interface allowing the connection of a CMOS camera sensor that supports speeds as high as 67.2 Mbytes/sec. Devices are available in LQFP100, LQFP144, and LQFP/BGA176 packages, with 512 kbytes to 1 Mbyte of flash.

The STM32F415 and STM32F417 parts add a cryptography/hash-encryption processor to the STM32F405 and STM32F407. The processor has hardware acceleration for AES (Advanced Encryption Standard) 128, 192, and 256; Triple DES (Data Encryption Standard); the MD5 (Message Digest 5) algorithm; and the SHA-1 (Secure Hashing Algorithm-1). The devices are in volume production, and prices begin at $5.74 (1000) for the STM32F407VET6 with 512 kbytes of flash and 192 kbytes of RAM in an LQFP100 package.

STMicroelectronics