UniPi 1.1 Lite and 1-wire bus connection?



  • Hi!

    I have UniPi 1.1 Lite expansions board connected to the Raspberry Pi 3. Documentation says that UniPi 1.1 Lite have 1-wire-bus connection (RJ45) as follows: Vcc = pins 4+5, GND = 3+8 and DQ = 6+7, pins 1+2 are not connected/used. I have tested RJ-cable pinout, all pins 1..8 are conneccted.

    I have tested 1-wire bus functionality with two (2) DS18B20 temperature sensors. It seems, that if I use pin 6 as DQ, I cannot read/found any device connected to the 1-wire bus. If I use pin 7 as DQ, both sensors are found on the 1-Wire bus.

    Sensor DS18B20 - 28C3951E020000DF 21.4°C
    Sensor DS18B20 - 2857851E020000CE 21.4°C

    Please confirm, is pin 6 really used as DQ pin, or have I forgotten something?

    Best regards,
    Timo


  • administrators

    Hello @viestivelho,

    1Wire has only one data pin from its design, and that is pin 7 on the master = the UniPi. Besides that we use another wire, pin 6, to serialize the bus as much as possible to maximize the reliability. That pin is wired only in the temperature sensors and HUBs which we provide.