Dallas 1-Wire Support
Preparation
- Will cover an example of a temperature sensor well known DS1820 other 1 wire IC's are supported too.
Default GPIO for 1-Wire is Pin #15 (ODROID-N2 / C4 - GPIOX.BIT7 ODROID-M1 - GPIO3.B2)
- Connection: With External-Supply
Pin 1 (Left): Ground (-)
Pin 2 (Middle): Pin #15 N2/C4: (GPIOX.BIT7) M1: (GPIO3.B2)
Pin 3 (Right): VCC (3.3V)
You also need to add a resistor from 4.7k to 10k between pin 2.
- Connection: Supplying the Parasite-Powered
Pin 1 (Left): Ground (-)
Pin 2 (Middle): Pin #15 N2/C4: (GPIOX.BIT7) M1: (GPIO3.B2)
Pin 3 (Right): Ground (-)
You also need to add a resistor from 4.7k to 10k between pin 2.
Enable 1-wire Bus
- If you use the kernel version more than 4.9.230(N2/C4), you should edit /media/boot/config.ini file to enable 1-wire by adding onewire to overlays variable.
- If you use the kernel version more than 5.15.x (N2/C4), or use ODROID-M1, you should only edit /boot/config.ini file to enable 1-wire by adding onewire to overlays variable.
; Device Tree Overlay overlay_resize=16384 overlay_profile=myproject overlays="" [overlay_myproject] overlays="onewire"
- To know the further information of Device Tree Overlay, please refer to this document.
- Check if your sensor is working:
- target
root@odroid:~$ lsmod w1_therm 16384 0 w1_gpio 16384 0 wire 45056 2 w1_gpio,w1_therm root@odroid:~$ cd /sys/bus/w1/devices root@odroid:/sys/bus/w1/devices# ls 10-000802f38c57 w1_bus_master1 root@odroid:~$
As you can see my sensor is detected as 10-000802f38c57, each sensor has a different id. So yours will be different.
- Read the temperature:
- target
root@odroid:/sys/bus/w1/devices$ cd 10-000802f38c57 root@odroid:/sys/bus/w1/devices/10-000802f38c57# cat w1_slave 33 00 4b 46 ff ff 03 10 30 : crc=30 YES 33 00 4b 46 ff ff 03 10 30 t=25562 root@odroid:/sys/bus/w1/devices/10-000802f38c57#
Temperature is t=25562 or 25.562 degree's Celsius.
- Multiple sensors can be connected on the same line as the draw below.
- target
odroid@odroid64:/sys/bus/w1/devices# ls 10-000802f38c57 10-000802f41d67 w1_bus_master1
Two sensors in parallel.
luke.go