Using devices with the I²C bus

The Raspberry Pi can support several higher-level protocols that a wider range of devices can easily be connected to. In this chapter, we shall focus on the most common bus, called I²C (I-squared-C). It provides a medium-speed bus for communicating with devices over two wires. In this section, we shall use I²C to interface with an 8-bit ADC. This device will measure an analog signal, convert it to a relative value between 0 and 255, and send the value as a digital signal (represented by 8 bits) over the I²C bus to the Raspberry Pi.

Getting ready

The I²C bus is not enabled in all Raspberry Pi images; therefore, we need to enable the module and install some supporting tools. Newer versions of Raspbian use Device Trees to handle hardware peripherals and drivers.

In order to make use of the I²C bus, we need to enable the ARM I²C in the \boot\config.txt file.

You can do this automatically using the following command:

sudo raspi-config

As shown in the following screenshot...