Reading data from I2C device in Embedded C - Mini Project: Build & Apply

Reading data from I2C device

📖 Scenario: You are working on a small embedded system that reads temperature data from a sensor connected via the I2C bus. The sensor's data register holds the temperature value you want to read.

🎯 Goal: Build a simple program that reads one byte of data from the sensor's data register over I2C and prints the temperature value.

📋 What You'll Learn

Create a variable to hold the I2C device address

Create a variable to hold the register address to read from

Use a function call to read one byte from the I2C device at the given register

Print the read temperature value

💡 Why This Matters

🌍 Real World

Reading sensor data over I2C is common in embedded systems like weather stations, thermostats, and IoT devices.

💼 Career

Embedded developers often need to interface with sensors using I2C to collect data for processing and control.

1

Set up I2C device and register addresses

Create a variable called device_address and set it to 0x48. Create another variable called temp_register and set it to 0x00.

Embedded C

# Create variables for device and register addresses
# Your code here

Need a hint?

The device address is usually given in hexadecimal. Use unsigned char for these variables.

2

Create a variable to hold the temperature data

Create a variable called temperature of type unsigned char to store the data read from the sensor.

Embedded C

unsigned char device_address = 0x48;
unsigned char temp_register = 0x00;

// Create a variable to hold the temperature data
# Your code here

Need a hint?

Use unsigned char for the temperature variable since the sensor returns one byte.

3

Read temperature data from the I2C device

Use the function i2c_read_byte(device_address, temp_register) to read one byte from the sensor and store it in the variable temperature.

Embedded C

unsigned char device_address = 0x48;
unsigned char temp_register = 0x00;
unsigned char temperature;

// Read one byte from the I2C device
# Your code here

Need a hint?

Call the i2c_read_byte function with the device and register addresses as arguments.

4

Print the temperature value

Use printf to display the text "Temperature: " followed by the value of temperature and a newline.

Embedded C

unsigned char device_address = 0x48;
unsigned char temp_register = 0x00;
unsigned char temperature;

temperature = i2c_read_byte(device_address, temp_register);

// Print the temperature value
# Your code here

Need a hint?

Use printf("Temperature: %u\n", temperature); to print the value as an unsigned integer.