How to Use STM32 Discovery kit LoRa, Sigfox, low-power wireless : Examples, Pinouts, and Specs

The STM32 Discovery Kit LoRa, Sigfox, Low-Power Wireless (manufacturer part ID: B-L072Z-LRWAN1) is a development board designed by STMicroelectronics. It is built around the STM32L072CZ microcontroller, which is part of the ultra-low-power STM32L0 series. This kit integrates LoRa® and Sigfox® communication capabilities, making it ideal for IoT applications requiring long-range, low-power wireless connectivity.

• Internet of Things (IoT) devices
• Smart metering and smart cities
• Industrial monitoring and control
• Asset tracking and geolocation
• Environmental monitoring
• Home automation

The STM32 Discovery Kit features Arduino Uno V3-compatible headers for easy prototyping. Below is the pinout for the Arduino header:

1. Powering the Board:

   • Connect the board to a computer or USB power source using a micro-USB cable.
   • Alternatively, supply 3.3V to the external power pins.

2. Programming the Board:

   • Use the on-board ST-LINK/V2-1 debugger to program the STM32L072CZ microcontroller.
   • Compatible IDEs include STM32CubeIDE, Keil MDK, and IAR Embedded Workbench.

3. Connecting Peripherals:

   • Use the Arduino Uno V3-compatible headers to connect sensors, actuators, or other peripherals.
   • For wireless communication, ensure the on-board antenna is not obstructed.

4. Wireless Communication:

   • Configure the LoRa® or Sigfox® stack using the STM32Cube software libraries.
   • Use the Semtech SX1276 transceiver for long-range communication.

• Power Management: Utilize the ultra-low-power modes of the STM32L072CZ to maximize battery life in IoT applications.
• Antenna Placement: Ensure the on-board antenna has a clear line of sight for optimal wireless performance.
• Firmware Updates: Regularly update the firmware using STM32CubeProgrammer to ensure compatibility with the latest software libraries.
• Debugging: Use the ST-LINK/V2-1 debugger for real-time debugging and troubleshooting.

The STM32 Discovery Kit can be programmed using the Arduino IDE with the STM32 core installed. Below is an example of sending a message over UART:

// Include the necessary library for STM32
#include <Arduino.h>

// Define UART pins
#define RX_PIN PA3  // UART RX pin
#define TX_PIN PA2  // UART TX pin

void setup() {
  // Initialize UART communication at 9600 baud
  Serial.begin(9600);
  while (!Serial) {
    // Wait for the serial port to initialize
  }
  Serial.println("STM32 LoRa Discovery Kit Initialized");
}

void loop() {
  // Send a message over UART every 2 seconds
  Serial.println("Hello from STM32 Discovery Kit!");
  delay(2000);  // Wait for 2 seconds
}

Note: Install the STM32 board package in the Arduino IDE before uploading the code.

1. Board Not Detected by Computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Check that the ST-LINK/V2-1 driver is installed on your computer.

2. Wireless Communication Fails:

   • Verify that the LoRa®/Sigfox® stack is correctly configured in the firmware.
   • Ensure the antenna is properly connected and unobstructed.

3. Power Issues:

   • Confirm that the board is receiving sufficient power (3.3V via USB or external source).
   • Check for short circuits or incorrect connections on the headers.

4. Programming Errors:

   • Ensure the correct microcontroller (STM32L072CZ) is selected in the IDE.
   • Update the ST-LINK firmware using the STM32CubeProgrammer tool.

Q: Can I use this board with batteries?
A: Yes, the board supports battery operation. Use the external power pins to connect a 3.3V battery.

Q: Is the board compatible with LoRaWAN®?
A: Yes, the board supports LoRaWAN® through the Semtech SX1276 transceiver and STM32Cube software libraries.

Q: Can I use this board with Arduino shields?
A: Yes, the board features Arduino Uno V3-compatible headers for easy integration with Arduino shields.

Q: How do I update the firmware?
A: Use the STM32CubeProgrammer tool to flash the latest firmware via the ST-LINK/V2-1 debugger.

Q: What is the range of the LoRa® communication?
A: The range depends on environmental factors but can reach up to several kilometers in open areas.