STMicro STM32L5 Cortex-M33 ARMv8-M MCU Family Targets Secure IoT Applications

STMicro STM32 microcontrollers have so far been based on Arm Cortex-M0/M0+, M3, M4, or M7 cores, although we’ve also seen a yet-to-be formally announced Cortex A7 variant shows up in Linux 4.17 with STM32MP157C.

The company has very recently announced a new family, namely the STM32L5 series, powered by an Arm Cortex-M33 ARMv8-M 32-/64-bit TrustZone enabled core clocked at up to 110 MHz, and equipped with on-chip SMPS for easy low power efficiency, USB FS device, and USB type-C PD Controller.

Two sub-families are part of the STM32L5 series:

STM32L552 with 256 to 512 KB of Flash memory and from 48 to 144-pin packages.
STM32L562 with 512 KB of Flash memory, and an additional encryption accelerator engine (AES, PKA, and OTFDEC).

Besides the extra HW crypto block both share the same key specifications:

MCU Core – Arm Cortex-M33 ARMv8-M core clocked at up to 110 MHz (+20% versus Cortex-M4) with FPU, TruztZone
Memory – 256 KB RAM
Flash – 256KB to 512KB flash
ST ART Accelerator – 8 KB of instruction cache allowing 0-wait-state execution from Flash memory and external memories; frequency up to 110 MHz, MPU, 165 DMIPS, and DSP instructions
Peripherals
- USB – 1x USB Full Speed interface, 1x USB type-C
- Analog-to-digital converter (ADC)
- 2x 12-bit power-gated digital-to-analog converters (DAC)
- 2x ultra-low-power comparators
- 2x operational amplifiers with external or internal follower routing and programmable-gain amplifier (PGA) capability.
- USART, SPI, I2C, CAN-FD
- 16- and 32-bit timers
- SAI + audio PLL
- Capacitive touch sensing
Security – Arm TrustZone, flexible software isolation, secure boot, key storage, and hardware cryptographic accelerators
Power Features / Consumption
- Operating Voltage – 1.71 to 3.6 V
- Embedded SMPS step down converter (optional)
- UCPD controller compliant with USB Type-C Rev. 1.2 and USB Power Delivery Rev. 3.0 specifications.
- Power consumption numbers:
  - 33 nA in shutdown mode
  - 3.6 µA in stop mode with full SRAM and peripheral states retention with 5µs wake-up time
  - Down to 60 µA/MHz in active mode
- EEMBC ULPBench: 402 ULPMark-CP score
Packages – LQFP48, QFN48, LQFP64, WLCSP81, LQFP100, UFBGA132, and LQFP144
Temperature Range – Standard temperature grade for consumer and commercial applications, or high-temperature grade specified from -40°C to 125°C for challenging environments

STM32L5 MCUs are expected to be found in industrial sensors or controls, home-automation devices, smart meters, fitness trackers, smartwatches, medical pumps or meters, and other applications.

STM32L5 series MCUs are sampling now, mass production should start in Q2 2019. The company is also showcasing its new microcontrollers at Arm TechCon 2018 until October 18. More details – but no documentation yet – can be found on the product page.

Thanks to Lucas for the tip.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.