STMicro Adds Secure 2-Core Version to LoRaWAN Wireless MCU

‘STM32WL55’ was revealed by the Italian-French joint venture STMicroelectronics as a new product of the ‘STM32WL series’ MCU that incorporates Sub-GHz wireless communication circuits. In January , the company publicly released the first product of the STM32WL “STM32WLE5” series *, and the second model is the latest product.

The first STM32WLE5 is a product which integrates on a single chip an ARM Cortex-M4 based MCU “STM32L4” and an RF transceiver circuit based on the “SX126x” from Semtech. With the inclusion of Arm Cortex-M0 +, this latest product, STM32WL55, is combined into one processor. It is possible to provide a margin to the application processing power of Cortex-M4, which is the main CPU core, by offloading the wireless communication stack processing and protection processing to Cortex-M0 +.

The RF transceiver circuit based on the SX126x can handle 150M to 960MHz and can handle different modulation methods, such as networking protocols for LoRaWAN and LPWA (Low Power Wide Area Network). For starters, it can handle the original protocol of LoRa modulation user’s LPWA, and Sigfox LPWA communication, wM-Bus (wireless Meter-Bus), (G) FSK/(G) MSK/BPSK modulation system.

The new product “STM32WL55” integrates an Arm Cortex-M4-based MCU “STM32L4”, a CPU core “Arm Cortex-M0 +”, and an RF transceiver compatible with LoRaWAN, etc. on a single chip.

By entrusting security processing to Cortex-M0 +, Cortex-M4, which is the main CPU core, has a margin in application processing capacity.

The overall operating frequency of the combined Cortex-M4 and Cortex-M0+ in the latest STM32WL55 product is 48MHz. It incorporates 256K flash memory bytes, 64K SRAM bytes, 12-bit AD converter, 12-bit DA converter, and authentication circuits such as an accelerator for 256-bit AES encryption. I 2 C, SPI, I 2 S, UART, USART, LIN etc are supported by the external gui.

The kit is a UFQ FPN 48-pin (7 mm x 7 mm) and a UFBGA 73-ball (5 mm x 5 mm). ‘NUCLEO-WL55JC1’ for 868M / 915M / 923MHz and ‘NUCLEO-WL55JC2’ for 433M / 470MHz are available on the production desk. Mass development of the STM32WL55 has begun. It has not announced the price. In addition, “STM32WLE4” and “STM32WL54” have also been commercialized by STMicroelectronics, which does not handle LoRa modulation but can handle (G) FSK / (G) MSK / BPSK modulation.