Through the addition of larger memories, enhanced graphics support, extra peripherals, and increased power-saving flexibility, the STM32L496 and STM32L4A6 microcontrollers (MCU) from STMicroelectronics extend the fusion of ARM Cortex-M4F core performance and proprietary low power technologies. Bigger on-chip RAM, now up to 320kB, complements the newly added ST Chrom-ART Accelerator graphics engine for smoother display performance in energy-conscious applications such as IoT devices and smart watches.
There is also up to 1MB Flash, an extra CAN interface, a camera interface and crystal-less Full Speed (FS) USB OTG. A high-pin-count UFBGA169 package option gives extra flexibility to exercise these new peripherals, which join the rich digital and smart analogue features shared with the STM32L476/486. The STM32L4A6 with hardware cryptographic acceleration implements SHA-256 and AES-128/192/256 algorithms.
Offering features unavailable in other low power MCUs, the new STM32L4 devices deliver both high core performance and low power efficiency. The EEMBC CoreMark score of 273 outperforms other low power cores, while the ULPBench score of 217 confirms greater energy efficiency. Active-mode current of 37µA/MHz enables longer runtime on small batteries and extends scope to create energy-neutral products powered from ambient sources.
ST has also extended the flexibility of the STM32L4 power architecture, giving developers the option to power the core from an external DC/DC converter for extra efficiency. The STM32L4 FlexPowerControl architecture includes a new shutdown mode for additional energy savings, alongside multiple independent core and peripheral supplies, and a separate VBAT domain with charging circuitry that gives flexibility to utilise or recharge battery energy. The rich selection of seven main STM32L4 low-power modes is also supported, with options such as retaining I/O levels and SRAM contents, each with several sub-modes that allow precision trimming of power consumption as application demand varies.
The STM32L4 MCU lines arrive with extensive ecosystem support, including STM32Cube tools and software, two Nucleo-144 boards, and the STM32L496 Discovery Kit (STM32L496G-DISCO) with on-board audio/graphics features and Arduino, Pmod and STMod+ connectivity support. The NUCLEO-L496ZG-P features an on-board DC/DC converter for powering the core directly, which allows developers to easily leverage the flexible power architecture in the most energy-conscious applications. The legacy-compatible NUCLEO-L496ZG is also available, and offers the same features as existing Nucleo-144 boards.