Scan for I2C Devices

Scan for I2C Devices

This tutorial shows how to create an I2C scanner using the NEXTuino BASE to detect the addresses of I2C devices connected to the board.

Prerequisites

  • Arduino IDE installed
  • NEXTuino BASE board

Example Code

The complete example is available on GitHub:
i2c_scanner.ino

Step-by-Step Guide

Step 1: Setup the Arduino Environment

  1. Connect your MICRO to your computer.
  2. Open the Arduino IDE.
  3. Ensure the appropriate board and port are selected in the Tools menu.

Step 2: Understanding the Code

Setup Function

void setup()
{
  Wire.setSDA(PIN_WIRE0_SDA);
  Wire.setSCL(PIN_WIRE0_SCL);
  Wire.begin();
  Serial.begin(9600);
  while (!Serial);
  Serial.println("\nI2C Scanner");
}
  • Wire.setSDA() / Wire.setSCL(): Sets the SDA and SCL pins for I2C communication.
  • Wire.begin(): Initializes the I2C bus.
  • Serial.begin(9600): Starts serial communication at 9600 baud.

Loop Function

void loop()
{
  byte error, address;
  int nDevices;
  Serial.println("Scanning...");
  nDevices = 0;
  for (address = 1; address < 127; address++)
  {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if (error == 0)
    {
      // Device found at this address
    }
    else if (error == 4)
    {
      // Unknown error at this address
    }
  }
  delay(5000); // Wait before next scan
}
  • Scans I2C addresses 1 through 126.
  • Wire.beginTransmission(address): Attempts to contact a device at the given address.
  • Wire.endTransmission() returns 0 if a device is found, 4 for an unknown error.

Step 3: Hardware Setup

  1. Connect your I2C device(s) to the NEXTuino BASE SDA and SCL pins.
  2. Ensure proper power and ground connections.

Step 4: Using the Scanner

  1. Open the Serial Monitor in the Arduino IDE.
  2. Set the baud rate to 9600.
  3. Observe the output — detected I2C device addresses are listed in hexadecimal.

Interpreting Results

  • Addresses are shown in hex format (e.g., 0x68).
  • Note down the addresses for use in your I2C-based projects.
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