How to Use B-L475E-IOT01A: Examples, Pinouts, and Specs

The B-L475E-IOT01A is a development board manufactured by STM32, designed to simplify the development of Internet of Things (IoT) applications. It is powered by the STM32L475 microcontroller, which is optimized for low-power operation. The board integrates a wide range of sensors, connectivity options (Wi-Fi, Bluetooth, NFC), and expansion interfaces, making it a versatile platform for prototyping and deploying IoT solutions.

• Environmental monitoring (temperature, humidity, air quality)
• Smart home devices
• Wearable technology
• Industrial IoT (IIoT) applications
• Prototyping for connected devices
• Battery-operated IoT systems

The B-L475E-IOT01A 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 power through the VIN pin (3.3V to 5V) for battery-operated applications.

2. Connecting Sensors and Peripherals:

   • Use the Arduino-compatible headers to connect external sensors or actuators.
   • For I2C devices, connect to the SDA and SCL pins. For UART devices, use the TX and RX pins.

3. Programming the Board:

   • Install the STM32CubeIDE or Arduino IDE (with STM32 support) on your computer.
   • Connect the board via USB and select the appropriate COM port in the IDE.
   • Write and upload your code to the board.

4. Using Built-in Sensors:

   • The board includes several onboard sensors (e.g., temperature, humidity, accelerometer). These can be accessed using STM32 HAL libraries or Arduino libraries.

• Power Consumption: Use the low-power features of the STM32L475 microcontroller to extend battery life in portable applications.
• Debugging: Use the integrated ST-LINK/V2-1 debugger for efficient debugging and programming.
• Firmware Updates: Keep the firmware updated to ensure compatibility with the latest libraries and tools.
• Connectivity: Ensure proper configuration of Wi-Fi and Bluetooth settings for reliable communication.

The following example demonstrates how to read temperature data from the onboard HTS221 sensor and print it to the serial monitor.

#include <Wire.h>
#include <HTS221Sensor.h> // Include the library for the HTS221 sensor

// Define I2C address for the HTS221 sensor
#define HTS221_I2C_ADDRESS 0x5F

// Create an instance of the HTS221 sensor
HTS221Sensor hts221(&Wire);

void setup() {
  Serial.begin(9600); // Initialize serial communication
  Wire.begin();       // Initialize I2C communication

  // Initialize the HTS221 sensor
  if (hts221.begin(HTS221_I2C_ADDRESS)) {
    Serial.println("HTS221 sensor initialized successfully.");
  } else {
    Serial.println("Failed to initialize HTS221 sensor.");
    while (1); // Halt execution if initialization fails
  }
}

void loop() {
  float temperature;

  // Read temperature from the HTS221 sensor
  if (hts221.getTemperature(&temperature)) {
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");
  } else {
    Serial.println("Failed to read temperature.");
  }

  delay(1000); // Wait for 1 second before the next reading
}

1. Board Not Detected by IDE:

   • Ensure the USB cable is properly connected and functional.
   • Verify that the correct COM port is selected in the IDE.
   • Update the ST-LINK driver if necessary.

2. Sensors Not Responding:

   • Check the I2C or SPI connections for external sensors.
   • Ensure the correct sensor address is used in the code.

3. Wi-Fi or Bluetooth Not Connecting:

   • Verify the network credentials (SSID and password) in the code.
   • Ensure the board is within range of the Wi-Fi router or Bluetooth device.

4. High Power Consumption:

   • Use the low-power modes of the STM32L475 microcontroller.
   • Disable unused peripherals to reduce power consumption.

Q: Can I use the B-L475E-IOT01A with the Arduino IDE?
A: Yes, the board is compatible with the Arduino IDE. Install the STM32 core for Arduino to get started.

Q: How do I update the firmware on the board?
A: Use the STM32CubeProgrammer tool to update the firmware via the USB interface.

Q: What is the range of the onboard Wi-Fi module?
A: The range depends on environmental factors but typically covers 30-50 meters indoors.

Q: Can I power the board with a battery?
A: Yes, the board can be powered using an external battery connected to the VIN pin (3.3V to 5V).