STM32WL series – integrated microcontroller with sub-GHz radio module

The STM32WL series offers a combination of the functionality and properties of a microcontroller with a sub-GHz radio module based on the Semtech SX126x solution in one integrated circuit. These systems use the architecture of Arm ® Cortex ® M4 and Cortex ® M0 + (single or dual core architecture can be selected) with a clock frequency of up to 48MHz, offering 64, 128 or 256kB FLASH memory and 20, 48 or 64kB RAM memory.

 

 

The microprocessor was developed using the same technology that was implemented in the development of the ultra-low power STM32L4 series of microcontrollers. This allows for ultra-low power consumption, which is suitable for IoT and LPWAN applications.

Wireless communication

The sub-GHz radio module located in the integrated circuit offers LoRa®, (G)FSK, (G)MSK and BPSK modulations, ensuring flexibility of cooperation with LoRaWAN®, Sigfox, W-MBUS, MIoTy® and other protocols. The module supports the frequency range from 150 to 960MHz with the possibility of choosing one of the two available output ports with a power between +22 max and + 16 min dBm.

STM32WL can cooperate with systems compliant with radio regulations such as: ETSI EN 300 220, FCC CFR 47 part 15 and with the Japanese ARIB T-108, as well as with Chinese regulatory requirements.

Peripheries

The integration of the microcontroller and the sub-GHz radio module on one chip allows to reduce the number of necessary components needed for the correct operation of the system, which reduces costs. The system is equipped with a rich set of peripherals: DMA, USART, LPUART, SPI, I2C, ADC, 43 GPIO and Timers. The module is also equipped with SMPS to reduce energy consumption, as well as the ability to select various operating modes, extending battery life.

 

Security

STM32WL microcontrollers enable the use of AES 128- / 256-bit hardware encryption, PCROP write/read protection and public-key accelerator with an elliptic curve cryptographic engine.

The dual core STM32WL5x series also includes advanced security features such as: Secure Key Management Services (SKMS), hardware isolation of secured areas, secure start and software update.

 

 

Antennas

Choosing the right antenna to work with the radio system can be key in many applications. An interesting choice may be the metal plate antenna PIFA PRO-OB-471 from the Swedish manufacturer Proant (operating frequency range 860 – 870MHz, 902 – 928MHz). PIFA antennas are characterized by high frequency stability even in demanding environmental conditions, such as the body or surrounded by metal elements. Although PIFA antennas are larger than, for example, ceramic antennas, they allow the placement of passive elements directly under the metal plate, guaranteeing the correct operation of the system, which allows the use of free PCB space under the antenna, e.g. for matching elements.

If for some reason the PIFA antenna cannot be used, it is worth taking a look at ceramic antennas, such as the AA701 from Unictron, operating in the frequency range: 863 – 870MHz.

 

Software suport

The STM32WL family of microcontrollers has development support in the form of  the STM32CubeWL MCU Package composed of the STM32Cube hardware abstraction layer (HAL) and the low-layer (LL) APIs, plus a consistent set of middleware components such as FatFS, SBSFU and FreeRTOS™, plus LoRaWAN and sub-GHz PHY connectivity services and many code examples.

 

Apply STM32WL module in your application – evaluation board Masters

In cooperation with STMicroelectronics, Masters designed an evaluation board based on the STM32WL module. Please contact our R&D department rd@masters.com.pl to receive the evaluation board, samples and additional technical support.

 

More information about STM32WL and LoRaWAN wireless communication can be found at:

STM32WL – nowy mikrokontroler ze zintegrowanym układem radiowym dalekiego zasięgu LoRa

LoRaWAN jako uzupełnienie infrastruktury Smart City IoT. Poznaj moduł Masters z układem STM32WL.

https://www.st.com/en/microcontrollers-microprocessors/stm32wl-series.html#overview

https://www.st.com/en/embedded-software/stm32cubewl