Master and Slave I2C Connection – How to Implement and Setup

What is a Master Slave I2C Connection using arduino

A master slave I2C connection is a type of communication protocol that enables two or more devices connected to each other on the same electrical or physical network to send and receive data. It stands for Inter-Integrated Circuit (I²C) and is a bidirectional, synchronous, serial communication interface. Specifically, it is a master-slave connection, meaning one device (the master) can control one or more other devices (slaves).

Overview of an I2C Connection

An I2C connection consists of two lines: the SDA line for data and the SCL line for the clock. Both are bidirectional and the SDA line is controlled by the master, while the clock is driven by the master’s clock frequency. The master device can initiate transfers to any slave device(s) connected to it.

The major advantage of an I2C master-slave connection is that it reduces the amount of wires used in a system. This reduced wiring saves money and space, as well as makes troubleshooting and installation much easier. Furthermore, the I2C protocol is designed to reduce electromagnetic noise within a system, allowing the connection to remain robust even when many slaves are connected.

How Does an I2C Connection Work?

Once the I2C connection is established, the master begins sending start bits which signals the slaves that a transfer is about to begin. After the start bits are sent, the master sends its 7-bit address. Next, the master then issues a request for data from the slave, or sends data to the slave. The slave then responds with an ACK signal or NACK signal, which indicates whether or not the slave was able to receive or send the data. Once the transfer is complete, the master sends a stop bit to signal the end of the transmission.

Applications for an I2C Connection

I2C connections are used in a variety of different applications, ranging from automotive systems to electronic appliances. The low-cost and high-speed capabilities of I2C make it the ideal choice for many types of products, including embedded systems and sensor networks. Because of its flexibility and reliability, I2C is a popular choice for connecting different components in a variety of applications.

In summary, an I2C connection is a type of communication protocol that allows two or more devices to send and receive data via two bidirectional lines. It is a master-slave connection, meaning one device (the master) can control one or more other devices (slaves). I2C is a robust and cost-effective way of connecting multiple components in various applications.

In a master-slave I2C connection using Arduino, the master device is typically an Arduino board that initiates communication with one or more slave devices, which could also be Arduino boards or other I2C-compatible devices. Here is an example code that demonstrates how to use a master-slave I2C connection using two Arduino boards:

Master code:

#include <Wire.h>

#define SLAVE_ADDRESS 0x12

void setup() {
  Wire.begin();
  Serial.begin(9600);
}

void loop() {
  Wire.beginTransmission(SLAVE_ADDRESS);
  Wire.write("Hello from Master!");
  Wire.endTransmission();

  delay(1000);

  Wire.requestFrom(SLAVE_ADDRESS, 6);
  while(Wire.available()) {
    char c = Wire.read();
    Serial.print(c);
  }
  Serial.println();

  delay(1000);
}

Slave code:

#include <Wire.h>

#define SLAVE_ADDRESS 0x12

void setup() {
  Wire.begin(SLAVE_ADDRESS);
  Wire.onReceive(receiveEvent);
  Serial.begin(9600);
}

void loop() {}

void receiveEvent(int bytes) {
  while(Wire.available()) {
    char c = Wire.read();
    Serial.print(c);
  }
  Serial.println();

  Wire.beginTransmission(SLAVE_ADDRESS);
  Wire.write("Hello from Slave!");
  Wire.endTransmission();
}

In this example, the master Arduino board sends a message "Hello from Master!" to the slave board with I2C address 0x12 every second, using the Wire.write() function. It then requests data from the slave board using Wire.requestFrom() function. The slave board receives the message using the Wire.onReceive() function and sends a response "Hello from Slave!" back to the master board. The master board prints the received messages using the Serial.print() function.

Note that the slave board also uses the Wire.begin() function to initialize the I2C connection with its own address, and Wire.available() function to check if there is data available to read.