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Original question:

P82B96: 30cm distance transmission

P82B96: Slave to Slave communication

user6075943
Prodigy 10 points
Part Number: P82B96

Hiya,

I'm looking for some help regarding wiring this P82B96(P). I am using it in this configuration which I believe to be correct. The intention is to transmit I2C up to 100m from master to slave. 

I am going to terminate this into an RJ45 screened connector and go over CAT6. I'll have to work out the resistor values for this unless you can give me a starting point to try.

My question is how to wire from a slave to a slave. (if it's possible) I have attempted to illustrate my question below.  Does each slave require two P82B96's to forward the signal on? Please note that each slave has a 12v supply.

  • 0
    TI__Guru 72821 points

    Hello,

    With CAT6 cable, I found a pdf online which states it has about 46pF per meter. at 100m, you will be sitting at around 4600pF. This device can support 4000pF so you are over by a little bit. Assuming this, you can pick your pull up resistor by knowing the capacitance.

    "My question is how to wire from a slave to a slave. (if it's possible) I have attempted to illustrate my question below.  Does each slave require two P82B96's to forward the signal on? Please note that each slave has a 12v supply."

    This device cannot be connected in series with each other on Sy/Sx side (it won't work). I would recommend you add your slaves parallel through the P82B96's TX/RX pins.

    Thanks,

    -Bobby