ARM-based microcontrollers offer single- cycle DSP instructions

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 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 a pin- and software-compatible upgrade from the STM32 F2 series with more SRAM; higher performance; and peripherals for imaging, connectivity and encryption. It operates at 168MHz compared with 120MHz for the F2, and provides single-cycle DSP-instruction support and an FPU, 192kB of SRAM compared with 128 kB for the F2, and 512 kB-1MB of embedded flash memory.

The F4 series provides ultrafast data transfers, with a seven-layer, multiple-AHB matrix and multiple DMA 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, and a less than 1μA real-time clock with less than 1-sec accuracy. It has 4kB of backup SRAM to save data in standby or battery-backup mode. Typical real-time-clock power consumption is less than 1μA 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 100GbE media-access controller (MAC) with IEEE 1588 Version 2 support; and two USB OTG ports, one of which has high-speed support.

The device includes a dedicated audio PLL and two full duplex inter-integrated-circuit-sound (I2S) ports. It also has as many as 15 communication interfaces, including six universal synchronous/ asynchronous receivers/ transmitters (USARTs) operating as fast as 10.5 Mbps, three SPIs operating as fast as 42Mbps, three I2C ports, two CAN interfaces, and one SDIO 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 168MHz.

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 full-speed/high-speed. It is available in WLCSP64, LQFP64, LQFP100, and LQFP144 packages with 1MB of flash.

STM32F407 products add a second FS-only USB OTG interface; an integrated 10- and 100GbE MAC supporting both an MII and an RMII, 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 67.2MB/sec. Devices are available in LQFP100, LQFP144, and LQFP/BGA176 packages, with 512kB-1MB 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 128, 192, and 256; Triple DES; the MD5 algorithm; and the SHA-1. The devices are in volume production, and prices begin at $5.74 (1,000) for the STM32F407VET6 with 512 kB of flash and 192 kB of RAM in an LQFP100 package.

STMicroelectronics