1-Wire technology

1-Wire is a device communication bus designed to exchange data over a single signal conductor together with a shared ground return. It was developed by Dallas Semiconductor, later part of Maxim Integrated, and its distinguishing feature is economy of wiring: a controlling device, called the master, can communicate with one or many slave devices using just one data line. Many 1-Wire parts can even draw their operating power from that same line, a technique known as parasitic power, so no separate supply wire is needed.

Communication on the bus is serial and is timed by the master, which generates pulses on the line to send and receive bits. Each 1-Wire slave carries a unique, factory-programmed identification number, which lets the master address individual devices on a shared bus and discover which devices are present. This addressing scheme makes the technology well suited to networks of small components spread across a system, where running many separate wires would be impractical.

Typical 1-Wire devices include digital thermometers and other sensors, small memory chips, real-time clocks, and identification or authentication tokens. Because the interface is simple and uses few pins, it is popular in hobby and embedded projects, where a microcontroller acts as the master and reads temperatures or other measurements from inexpensive sensors. The combination of single-wire data, optional parasitic power and unique device addressing is what makes the approach distinctive among low-speed device buses.

Frequently asked questions

Why is it called 1-Wire?

Devices communicate over a single data line plus a common ground, and many can also draw power from that same line.

How are individual devices identified on the bus?

Each device has a unique factory-programmed identification number, letting the master address and locate specific devices.

What is 1-Wire commonly used for?

Digital sensors such as thermometers, small memory chips, real-time clocks, and identification or authentication tokens.