STMicroelectronics has introduced two new models in the STM32U3 ultra-low-power Arm Cortex-M33 microcontroller family: the STM32U3B5 and STM32U3C5 MCUs. These feature up to 640 KB SRAM and 2 MB flash, plus an HSP (hardware signal processor) accelerator, enabling AI/ML workloads using energy harvesting alone.
The new chips maintain clock speeds up to 96 MHz with a near-threshold design (down to 0.65 V), achieving 117 Coremark/mW power consumption in active mode, and operating up to an ambient temperature of 105°C. They now offer one more group of interfaces, totaling four SPI and I2C, two I3C and CAN-FD, and five UARTs, along with five additional 16-bit timers, totaling 10. The STM32U3C5 includes a cryptocore to enhance encryption and decryption, supporting the CCB (Coupling and Chaining Bridge) security feature, not present in the STM32U3B5.
ST STM32U3B5/C5 key features and specifications:
- MCU Core
- 32-bit Arm Cortex-M33 CPU @ 96 MHz with TrustZone and FPU
- Performance
- 1.5 DMIPS/MHz (Dhrystone 2.1)
- 395.4 CoreMark (4.12 CoreMark/MHz)
- ART Accelerator with DSP instructions
- Mathematical coprocessor – Hardware signal processor (HSP) for digital signal and artificial intelligence processing
- Memory/Storage
- 640 KB SRAM, including 384 KB with hardware parity check
- 2 MB dual-bank flash with ECC
- OCTOSPI external memory interface supporting SRAM, PSRAM, NOR, NAND, and FRAM memories
- SDMMC interface
- Peripherals
- Up to 114x GPIOs with interrupt capability, most 5 V-tolerant, and up to 14x I/Os with independent
- Up to 114x GPIOs with interrupt capability, most 5 V-tolerant, and up to 14x I/Os with independent