STM32WL – microcontroller with integrated LoRa® long-range radio chip

 

The STM32WL series offers a combination of functionality and features of a microcontroller with a radio microcontroller operating in the Sub-GHz frequency range. The microcontrollers  are made in SoC technology and use Arm® Cortex® M4 and Cortex® M0+ architecture (single or dual core architecture can be selected depending on the chip version). They are perfectly suited for a wide range of industrial and consumer applications around the world.

The growing market demand for long-range communication underlies the development of the STM32WL microcontroller. In line with the idea of the STM32W families, it combines a microcontroller and a radio chip that supports several modulations, so that its application is wide and each user can adapt the technology to his own needs. LoRa® is distinguished by the ability to achieve long radio communication distances, which, depending on propagation conditions and the antennas used, can reach up to several kilometers. This is due, among others, to the use of band below 1 GHz and the CSS (Chirp Spread Spectrum) technology. Such an advantage has a very practical meaning wherever there is a need of sending data over long distances. A good example is the use of STM32WL microcontrollers in utility meters such as gas meters, water meters or energy meters. In this way, reading the consumption information can be done automatically. Another example of use is sensors, e.g.: monitoring the state of liquid in tanks, number of free parking spaces, temperature, monitoring livestock, etc.

The microcontroller used is based on the well-known Arm® Cortex®-M4 and Cortex® M0+ cores, and the radio chip is based on the SX126x IP core and can operate not only with LoRa® modulation but also supports many standard modulations, making it a flexible fit for wireless applications.

The chip was developed using technology that is used in the STM32L4 series microcontrollers, so the STM32WL contains a similar set of digital and analog peripherals and also features very low power consumption ensuring long battery life for the final application.

 

Wireless communication

The radio chip found in the STM32WL offers LoRa®, (G)FSK, (G)MSK and BPSK modulations providing the ability to work with LoRaWAN®, Sigfox, W-MBUS, mioty®, Zeta or protocols developed for a specific IoT application, including the ability to create a proprietary protocol. The operating frequency range is 150 to 960MHz with a choice of two available power amplifiers of +22 dBm or +15 dBm, enabling coverage of a wide range of unlicensed ISM sub-GHz radio band needs worldwide.

The radio interface complies with standards including ETSI EN 300 220, EN 300 113, EN 301 166, FCC CFR 47 part 15, 24, 90, 101 and Japanese ARIB STD-T30, T-67, T-108.

System peripherals

Integration of microcontroller and sub-GHz radio chip on a single chip allows to reduce the number of necessary components needed for proper operation of the system, which reduces costs. The chip is equipped with a rich set of peripherals: DMA, USART, LPUART, SPI, I2C, ADC, RTC, up to 43 GPIOs, Timers. as well as an SMPS  to reduce power consumption and the ability to select different operating modes extending battery life.

To order STM32WL microcontrollers, receive samples and get additional support, please contact us by sending an inquiry at: masters@masters.com.pl

Security

STM32WL microcontrollers enable AES 128/256-bit hardware encryption, PCROP write/read sector protection, a public key accelerator with an elliptic curve-based cryptographic engine, and a built-in random number generator.

The dual-core STM32WL5x series includes additional more advanced security features such as Key Management Services, Secure firmware install (SFI), Secure firmware update (SFU), Secure sub-GHz MAC layer and more.

It is worth remembering that the STM32WL microcontroller is covered by a special manufacturing warranty called longevity commitment, which in this case lasts 10 years and can be renewed every year for another 10-year period.

Software support

The STM32WL family of microcontrollers comes with software support in the form of the STM32CubeWL package consisting of HAL (Hardware Abstraction Layer) and LL (Low Layer) libraries, a consistent set of add-on software components such as FatFS, SBSFU, FreeRTOS®, as well as many LoRaWAN® and Sigfox sample codes and stacks.

Antennas

Choosing the right antenna to work with an RF chip can be crucial in many applications. An interesting choice may turn out to be the antenna offer of Pulse company, which has in its offer SMD ceramic, PIFA, helical and PCB internal antennas. PIFA antennas are characterized by high frequency stability under changing environmental conditions. It’s also worth to have a look at Unictron’s ceramic antennas, among others, such as AA701 working on the frequency range: 863 – 870MHz, which, thanks to the TELA solution, enables independent tuning of the antenna frequency to a given application. The antenna should be placed in the middle position at the edge of the PCB. If a corner position is required, then the C812D5 antenna can be used.

Use STM32WL chip in your application – Masters evaluation board

The distinguishing feature of the Masters evaluation board with STM32WL is that it provides the user with a prototyping platform containing the most essential components necessary for the prototyping stage without running additional cables.

The evaluation board includes a built-in PIFA and ceramic antenna and is equipped with an SMA connector for external antennas. This provides testability wherever a high energy gain external antenna is a requirement during application adaptation.

Switching between the PIFA antenna, ceramic antenna, and SMA connector for maximum usability and convenience is done by software. In addition, the HTS221 temperature and humidity sensor is used as a simple way to provide real-time and time-varying data during tests. The use of batteries makes the chip a standalone solution for first stage prototyping in PoC testing.

Evaluation board NUCLEO-WL55JC1 is available in Masters

https://www.youtube.com/watch?v=ZF165GRLy50

 

STM32WL portfolio:

More information about STM32WL and LoRaWAN wireless communications:

STM32 WL

STM32WL_series_product_overview

STM32 Cube WL

STM32WL Wireless series the world’s first SoC enabling LoRa®, (G)FSK, (G)MSK, BPSK

STM32WL Online Training

LoRa connectivity for Condition-Based and Predictive Maintenance in Smart Industry

 

Contact

Masters is the official distributor of STMicroelectronics products. If you are interested in receiving samples or want to talk about your project and possibilities of using STMicroelectronics components, please contact us at masters@masters.com.pl or directly with chosen Customer Service Office. We will advise the most appropriate solution to your needs.