Enhanced “Data Batching” Underlies MCUs’ Power-Saving Ability
The STM32 Dynamic Efficiency microcontroller family improves the power-saving performance of data batching, a technique used in Google’s latest Android 4.4 (KitKat) operating system to maximize battery life, and extends those advantages to applications beyond smartphones/tablets. For example, the STM32F411 MCUs, thanks to higher-performance design with lower dynamic power, will fit well into sensor-hub applications. Their Batch Acquisition Mode (BAM) saves up to 50% extra data by storing sensor data directly into SRAM while the CPU core sleeps, according to ST. In addition to the another power-saving mode—FlashSTOP—the MCUs feature the ARM Cortex-M4 processor core with DSP and floating-point unit, up to 512 kbytes of flash, and up to 128 kbytes of SRAM. They also leverage ST’s ART Accelerator branch cache, 90-mm process, and voltage-scaling capability to boost performance: The devices achieve RUN mode current of 100 µA/MHz executing EEMBC CoreMark code from flash with peripherals off, and can run up to 100 MHz to delivers 125 DMIPS. Comm interfaces include three I2C ports (up to 1 Mbit/s), three USARTs (up to 12.5 Mbits/s), USB 2.0 OTG Full Speed interface with embedded PHY, five SPI ports (up to 50 Mbits/s) with five I2S audio interfaces, and an SD/MMC.