Implements low-power techniques including power gating, real-time acceleration, adaptive voltage scaling, and reduced-power operating modes

By Alex Pluemer, contributing writer

STMicroelectronics
recently introduced the STM32L5 microcontroller (MCU) series
featuring the Arm Cortex-M33 core with Arm’s TrustZone hardware-based security.
The MCUs provide an ultra-low-power, highly secure solution for connected
devices from industrial sensors and controls and home automation devices to
smartwatches and fitness trackers. While Arm’s TrustZone security enhances
protection for IoT devices, the STM23L5 series also supports secure boot, key
storage, hardware cryptographic accelerators, and flexible software isolation.

The new MCU
series leverages STMicroelectronics’ know-how in low-power technology by
implementing methods like power gating, real-time acceleration, adaptive
voltage scaling, and reduced-power operating modes to reduce power consumption
to as low as 33 nA in shutdown mode. The devices achieved 402 (non-certified)
ULPMark-CP in the Embedded Microcontroller Benchmarking Consortium’s (EEMBC)
ULPBench.

The STM23L5 MCUs
provide consumer and industrial interfaces such as USB Type-C, USB Power
Delivery, and CAN FD as well as a variety of analog and integrated digital
peripherals.

Smart analog
features include an analog-to-digital converter, two power-gated digital-to-analog
converters, two ultra-low-power comparators, and two operational amplifiers with
programmable-gain amplifier (PGA) functionality and external or internal follower
routing.

Digital
peripherals include USB Full Speed with dedicated supply and a UCPD controller
compliant with USB Type-C Rev. 1.2 and USB Power Delivery Rev. 3.0
specifications.

Implementing the
ST ART accelerator at 110 MHz allows STM32L5 series MCUs to provide up to 165
DMIPS/427 CoreMark. The ST ART accelerator now supports internal flash memory
and external memory with an 8-Kbyte instruction cache for greater efficiency in
case the software runs out of external memory, said ST.

Other features
include 512-Kbyte dual-bank flash memory, which enables read-while-write
operations and provides a highly secure environment by implementing error
correction code (ECC) with diagnostics; a 256-Kbyte SRAM; and support for high-speed external memory including
single, dual, quad, or octal SPI and HyperBus flash or SRAM and an interface
for SRAM, PSRAM, NOR, NAND, or FRAM.

The STM32L5 MCUs
are available in standard temperature grade for conventional applications or
high temperature grade (–40°C to 125°C) for harsher environments. Samples are
available. Volume production is scheduled to begin in Q2 2019.