Using devices with the I2C bus

Raspberry Pi can support several higher-level protocols that a wide range of devices can easily be connected to. In this chapter, we shall focus on the most common bus, called I-squared-C (I²C). 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.

The advantages of I²C can be summarized as follows:

• Maintains a low pin/signal count, even with numerous devices on the bus
• Adapts to the needs of different slave devices
• Readily supports multiple masters
• Incorporates ACK/NACK functionality for improved error handling

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...