BAM! Microcontrollers pack power efficiency into smartphones

Android 4.4 uses a low-power sensor hub to manage “always-on” sensors like accelerometers or pressure sensors, allowing the main system processor to consume less battery energy. The microcontrollers are engineered to deliver more performance with lower dynamic power and higher integration. A Batch Acquisition Mode (BAM) saves up to 50% extra power by storing sensor data directly into SRAM while its own CPU core sleeps. The core wakes briefly to process this stored data before returning to power-saving mode.

The microcontroller can be used in a wide variety of industrial and consumer applications, and brings the advantages of BAM and other power-saving innovations including Flash-STOP mode to applications like industrial controls, medical monitors, building automation, and wearable technology. A choice of compact packages down to 3.034mm x 3.22mm allows use where space is tight.

The device features the ARM Cortex-M4 processor core with DSP and Floating-Point Unit (FPU), and has up to 512Kbyte of Flash with high SRAM capacity of up to 128Kbyte. It leverages ST’s ART Accelerator branch cache, 90nm process, and voltage-scaling capability to minimise dynamic power and boost processing performance It is the first device in the industry’s first M4-class to achieve RUN mode current of 100µA/MHz executing EEMBC CoreMark code from Flash with peripherals off while also being able to run up to 100MHz to deliver 125DMIPS. Current in STOP mode is also very low at just 10µA typical with all SRAM content and context saved.

With the option of an extended temperature range of -40°C to 105°C, low-voltage supply down to 1.7V, and rich peripherals, the device can be deployed in demanding environments and applications. The peripheral set includes a 12-bit 16-channel ADC up to 2.4Msample/s, up to 11 timers including motor-control timer and general-purpose 16-bit and 32-bit timers, and versatile communication interfaces. These include three I²C ports up to 1Mbit/s, three USARTs up to 12.5Mbit/s, a USB 2.0 OTG Full Speed interface with embedded PHY, five SPI ports up to 50Mbit/s with five I²S audio interfaces, and an SD/MMC interface. These features are available with all package options, including the lowest pin-count devices.

The new microcontrollers is supported with the STM32 Nucleo open hardware platform and STM32Cube software tools and embedded software. A Discovery kit will also be available in Q4 2014.