STMicroelectronics along with Murata is here with the STM32 Cellular IoT Discovery kit. The kit, also identified as B-L462E-CELL1, offers up to 4G LTE cellular connectivity through an eSIM. The STM32 Cellular IoT Discovery kit is packed with many onboard sensors and a tiny OLED display. Together with an ultra-low-power STM32L4, the kit is well suited for embedded developers and IoT evangelists.
Previously we had seen the STM32 Nucleo-64 development board, which featured many communication capabilities. Nucleo boards provide flexible prototyping due to their support for Arduino Uno headers. STM32 Cellular IoT Discovery kit is somewhat similar to it but contains a lot of additional components. Discovery series kits usually feature a display, onboard sensors, and LEDs in contrast to the Nucleo boards. So, if you need to do some rapid prototyping, you can go with Nucleo boards; otherwise, Discovery kits are ideal for your applications.
Cellular IoT Discovery kit’s central highlights
STM32 Cellular IoT Discovery kit is primarily focused on applications that involve wireless connectivity. The ST4SIM-200M embedded SIM is compliant with 2G / 3G / 4G (LTE) / CDMA / NB-IoT / CAT–M networks. Hence, it makes it much more portable as it won’t rely on Wi-Fi hotspots for IoT applications. The eSIM is GSMA SGP.02 v3.2 certified and is pre-programmed with a bootstrap connectivity profile from Truphone, an ST Authorized Partner. With this SIM, the STM32 Cellular IoT Discovery kit also supports Over-The-Air (OTA) updates. The ST4SIM-200M eSIM also provides strong resistance to cellular connectivity attacks, thus offers enhanced protection against cyber-attacks.
Another highlight of the STM32 Cellular IoT Discovery kit is its ultra-low power consumption, thanks to the STM32L4 MCU. The STM32L4 draws about 2µA in STOP 2 mode, and the cellular chipset draws less than 1.4µA in Power Saving Mode (PSM). For applications like smart-city, smart-industry and wearable applications, the Cellular IoT kit is ideal with such capabilities. The kit also houses a 0.96-inch 128×64 white OLED screen with SPI for ease of debugging.
Technical Specifications of Cellular IoT Discovery kit
STM32 Cellular IoT Discovery kit features the LBAD0ZZ1SE module from Murata. An Arm Cortex-M4 based 32-bit STM32L462RE MCU powers this module. There are 512 Kbytes of Flash memory and 160 Kbytes of RAM along with it. Additionally, 64 Mbytes of onboard Quad-SPI Flash memory from Micron is exclusive with the 1 MByte of Quad-SPI Flash memory inside the module. The kit also has MAX9867ETJ+ which is an ultra-low-power stereo audio codec. Portable consumer devices such as mobile phones and portable gaming consoles usually have this codec.
There are also a bunch of sensors on the STM32 Cellular IoT Discovery kit itself. These include LSM303AGR accelerometer-magnetometer, HTS221 relative humidity and temperature sensor, and LPS22HH pressure sensor. Together with this set of onboard sensors, the kit simplifies the development of motion and environmental monitoring solutions. There are also three user LEDs and two push buttons (user and reset). For powering the kit, there are five options- ST-LINK USB, User USB, UART USB, Power USB, or three AAA batteries. With this, the user gets the flexibility to choose the power supply which suits the application most. The device also has the following connectors-
- SMA antenna connector
- Two 50-pin 2.54 mm pitch headers
- micro-SIM card slot
- 3.5 mm CTIA stereo headset jack including analog microphone input
- USB Micro-B connectors for power, USARTs, USB device, and ST-LINK/V2-1
- mikroBUS expansion connectors
- ESP‑01 expansion connector
- Grove Seeed Studio™ breadboard, I2C, and UART expansion connectors
Software aspects and availability of the kit
Coming to the software part, the kit supports a wide range of Integrated Development Environments (IDEs). These include IAR Embedded Workbench, MDK-ARM, and STM32CubeIDE. X-CUBE-CELLULAR, a STM32Cube software expansion package, drives the kit and supports the Berkeley (BSD) sockets application programming interface (API). BSD provides standardized functions-calls for Internet communications. Thus, the user can easily connect their prototypes to the internet without developing an AT-command driver to control the modem.
The STM32 Cellular IoT Discovery kit retails for $74 on its official product page.
The product page is the source of all technical specifications and images used.
Harsh Chaudhary is an engineering student currently pursuing Electrical Engineering. He’s a robotics and tech enthusiast and likes to write about stuff related to IoT and embedded systems. His vision is to use Robotics to make the life of humans easier.