UniPi, RPi3 and Onewire 2 bus masters



  • I'm using the UniPi board v.1.1 and Raspberry Pi 3 with Raspbian jessie from 27th May 2016. I also have the DS18B20 sensor which was supplied with the UniPi kit. After installing Raspbian I have ran the script file to install UniPi support and enable I2C with RTC etc.

    I have 2 pcs of these units, the first one detects 1 Onewire Bus Master as /sys/devices/w1_bus_master1 with the sensor ID detected properly. I can read the sensor no problem.

    The second unit is identical BUT I get 2 Bus Masters: /sys/devices/w1_bus_master1 and /sys/devices/w1_bus_master2. There is no other device in the bus, only the sensor and the DS2482 on board. The sensor appears in Bus Master 2 and the Bus Master 1 contains dummy devices with IDs 00-080000000000, 00-880000000000 and 00-f00000000000. Sometimes there is only one dummy device ID in there and sometimes several, the ID numbers change randomly.

    Why is the other unit different from the other? I'm trying to make 2 identical devices so our customer can use the same project file on Codesys apart from the sensor ID of course.

    What I have tried: reboot the system and re-flash the same raspbian image. Any ideas? Is the other UniPi faulty? Or maybe the Raspberry Pi?

    P.S. the RTC works just fine on both units.


  • administrators

    Hello, can you paste output of i2cdetect -y 1 on the second unit?