Mastering Wire Library in Arduino Uno: Sending Large Numbers Over I2C

When working with the Arduino Uno, you may encounter situations where you need to send large numbers over the I2C protocol. In this article, we will explore how to break down these numbers into individual bytes and reassemble them on the receiving end using the Wire library.

The first step in sending large numbers is to understand the limitations of the I2C protocol. On most Arduino boards and ATmega chips, integers are 16-bit, meaning they occupy two bytes. This means that if you try to send an integer larger than 255, it will not work as expected. To overcome this limitation, we need to split the large number into individual bytes and send them over I2C.

One way to do this is to use the Wire library's transmit function, which allows us to send a single byte at a time. We can also use the receive function to read the individual bytes from the receiving device and reassemble them into the original number.

To illustrate this process, let's take an example of sending a large number using the Wire library. Suppose we want to send the value 3000 over I2C. First, we need to split this value into individual bytes:

```

byte daysOfTheWeek = (byte)delay(3000);

```

In this example, we use the `delay` function to wait for console opening and then convert the value to a byte using the `(byte)` cast.

Next, we can send each of these bytes over I2C using the Wire library's transmit function:

```

Wire.beginTransmission(address);

Wire.write(daysOfTheWeek >> 8);

Wire.write(daysOfTheWeek & 0xFF);

Wire.endTransmission();

```

In this example, we use the `beginTransmission` function to initiate a transmission and then send each of the two bytes that make up the original value. We use bitwise operators (`>>` and `&`) to extract each byte from the original value.

On the receiving end, we can read each of these bytes using the Wire library's receive function:

```

Wire.requestFrom(address, 2);

int receivedValue = (Wire.read() << 8) | Wire.read();

```

In this example, we use the `requestFrom` function to request two bytes from the sending device and then use bitwise operators (`<<` and `|`) to reassemble these bytes into the original value.

By following these steps, you can master the art of sending large numbers over I2C using the Wire library in Arduino Uno. With this knowledge, you'll be able to overcome the limitations of the I2C protocol and send data efficiently between devices.

Wire library arduino uno