One-Wire Devices

Introduction

Many sensors communicate using the One-Wire protocol. Adding support to the Omega2 for One-Wire devices offers many additional use cases.

Onion makes available a sample One-Wire device tree overlay package that sets up a One-Wire bus master on GPIO2. This GPIO choice was semi arbitrary - chosen because GPIO2 is exposed on both the Omega2 and Omega2S and isn’t multiplexed with other commonly used functionality.

Users that need to use a different pin, other than GPIO2, can create their own customized version of the onion-dt-overlay-w1-gpio package.

Use the onion-dt-overlay-w1-gpio Device Tree Overlay package to enable a software-based One-Wire master to your device.

Installation

To install the Device Tree Overlay package, you must first update your package list:

opkg update
opkg install onion-dt-overlay-w1-gpio

After installing the package, reboot the device.

How One-Wire is used

For more information on using One-Wire, see the following One-Wire article.

Source Code

The Device Tree Overlay package is part of the onion-dt-overlay package.

The DTS fragment that enables this functionality can be found in the OnionIoT/OpenWRT-Packages GitHub repository at: https://github.com/OnionIoT/OpenWRT-Packages/blob/openwrt-23.05/onion-dt-overlay/src/w1-gpio.dts

The package definition can be found at: https://github.com/OnionIoT/OpenWRT-Packages/blob/openwrt-23.05/onion-dt-overlay/Makefile