STMicroelectronics has reduced the power required to operate a sophisticated 32-bit microcontroller to a new low level with the introduction of its STM32L4 series of MCUs.
The first two microcontrollers in the series, the STM32L476 and STM32L486, feature an 80MHz ARM® Cortex®-M4 core with DSP and floating-point unit. This low-power core is combined in the STM32L4 devices with the ST ART Accelerator™, which provides for zero-wait execution of instructions from Flash.
This combination of low-power technologies enables the devices to achieve up to 100DMIPS while drawing just 100μA/MHz. Up to 1Mbyte of dual-bank Flash and 128kbytes of SRAM support sophisticated applications and read-while-write capability.
The ultra-low power consumption of these new MCUs has been verified in independent testing against the standard EEMBC™ ULPBench® benchmark: in tests comparing the efficiency of various ultra-low-power microcontrollers, the STM32L476 and STM32L486 scored 123, the best in the industry.
Other low-power technologies implemented by ST in the STM32L4 microcontrollers include:
• dynamic voltage scaling to balance power consumption with processing demand
• the FlexPowerControl architecture
• seven power-management modes with sub-mode options. These include Stop, Stand-by, and Shut-down modes, in which current is as low as 30nA
• Batch acquisition mode for efficient data exchange with communication peripherals while in low-power mode
The STM32L476 and STM32L486 also feature three 12-bit ADCs operating at up to 5Msamples/s. Hardware oversampling enables the devices to achieve an upscaled 16-bit resolution.