This document will explain how to use 1-Wire on Khadas SBC. You will learn how to turn it on and how to get sensor data through 1-Wire.

Edit /boot/env.txt to add onewire to overlays.

e.g.

overlays=uart4 pwm_ao_a pwm_f i2c0 onewire

Reboot to effect.

Here we attach a 1-Wire device DS18B20 temperature sensor to the 1-Wire bus.

• Enter the driver directory:

khadas@Khadas:~$ cd /sys/bus/w1/devices
khadas@Khadas:/sys/bus/w1/devices$ ls
28-0119395ebf91  w1_bus_master1

• You can see the node of ds18b20 is 28-0119395ebf91. Enter this directory:

khadas@Khadas:/sys/bus/w1/devices$ cd 28-0119395ebf91
khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ ls
driver  id  name  power  subsystem  uevent  w1_slave

• Read w1_slave file will get the temperature value:

khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ cat w1_slave
b1 01 4b 46 7f ff 0c 10 d8 : crc=d8 YES
b1 01 4b 46 7f ff 0c 10 d8 t=27062

• Physical pins of 1-Wire bus: