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TCA9548A: Does each output port slave need a unique slave address

Roland Feibert31
Intellectual 710 points
Part Number: TCA9548A

Hello,

For diagram above, this has 1 slave per output port.

Do each of the 8 slaves on TCA address 0x70 need a unique address? Or can I have the same address for all 8 slaves?

Can the SMBus talk to each output port, for example, on TCA9548A addr 0x70, adequately with same address for all slaves? I'm guessing that I need unique slaves addresses across all output ports.

Can SMBus distinguish TCA 0x70 port 1 slave from TCA 0x71 port 1 slave if both slaves have the same address? Or do I need unique slave addresses across TCA devices as well?

For diagram above, this has 4 slaves per output port. 4 slaves should contribute much less than max capacitance allowed per bus.

Do I need unique slave addresses for each of the 4 slaves on an output port? Or can I have same address for all 4 slaves on output port? Guessing I need unique slave addresses on bus.

Do I need unique slave addresses for each of the 4 slaves between output ports?

For instance, can I have output port 1 slave addresses of 1, 2, 3, 4 and output port 2 slave addresses of 5, 6, 7, 8? I'm guessing this is what I have to do.

I'm guessing that I need unique slaves addresses across all slaves on an output port bus, AND unique slave addresses across all output ports.

Probably looking to implement something similar to block diagram 2 above, uses less TCA chips.

Thanks, Roland

  • +1
    Guru 316220 points

    All I²C devices on all bus segments that are enabled at the same time must have unique addresses.

    In diagram 1, all 24 slaves can use the same address if at most one port is enabled.

    In diagram 2, the four slaves on each port need unique addresses, but you can reuse those addresses on other ports if at most one port is enabled.