MCUs Are Low On Power, High On Security
By Mat Dirjish
STMicroelectronics’ ultra-low-power STM32L5x2 microcontrollers (MCUs) put emphasis on security for IoT applications. Operating at clock frequencies to 110 MHz, the MCUs start from an Arm Cortex-M33 32-bit RISC core with Arm TrustZone hardware-based security. STM32L5x2 MCU users have the freedom to include or exclude each I/O, peripheral, or area of Flash or SRAM from TrustZone protection, allowing isolation of sensitive workloads.
Additionally, TrustZone provides support for secure boot, read-out and write protection for SRAM and Flash, and cryptographic acceleration, including AES 128/256-bit key hardware acceleration, public key acceleration (PKA), and AES-128 On-The-Fly Decryption (OTFDEC). Carrying certification to PSA Certified Level 2, the STM32L5 devices also support active tamper detection and secure firmware installation.
Paired with protection features, the MCUs exploit proprietary ultra-low-power techniques like adaptive voltage scaling, real-time acceleration, power gating, and multiple lower-power operating modes. Other features include:
- 512 KB of dual-bank Flash
- 256 KB of SRAM
- Support for high-speed external memory including single, dual, quad, or octal SPI and Hyperbus Flash or SRAM
- An interface for SRAM, PSRAM, NOR, NAND, or FRAM.
- 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
- An analog-to-digital converter
- Two power-gated digital-to-analog converters
- Two ultra-low-power comparators
- Two operational amplifiers with external or internal follower routing and programmable-gain amplifier (PGA) capability
STM32L5x2 MCUs are available now in standard -40°C to +85°C or high -40°C to +125°C temperature ranges. Pricing starts at $2.60 each/1,000. For deeper insights and illuminations, peruse the STM32L5x2 MCU overview and the STM32L5: The New Security Flagship with TF-M, TrustZone.