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TCA9548A: TCA9548A Bus Enable

Part Number: TCA9548A

I have multiple devices connected on each port of the TCA9548A device. The devices that are connected will run as master to configure from an EEPROM also on the bus. I would like to confirm that the TCA9548A device will NOT hold the I2C lines low/high and allow the device on the bus to act as master even if the port is not enabled?

For Example: 

Bus Device 1 Device 2 Port Reference
SD0/SC0 EEPROM A Clocking Chip A A
SD1/SC1 EEPROM B Clocking Chip B B


SD2/SC2

EEPROM C Clocking Chip C C

Can Port A be enabled via TCA9548A, but Port B (Clocking Chip B I2C master gets programmed from EEPROM B) and Port C can still operate (ie their I2C busses will not be hindered in any way since the TCA9548A will not have those ports enabled)?

Thank you!

Julia

  • Hey Julia,

    TCA9548A will keep the main bus and the secondary channels isolated if the the channels are not enabled. In your example you stated channel 0 (Port A) is enabled and the other channels are disabled so the main channel will only connect to port A and communication is possible between this port only. Ports B and C will remain isolated and SCL/SDA will be held high unless another master is on port B or C in which case they can communicate.

    To reiterate, if the channel is not enabled then it is isolated and free to communicate with it's own "port" without interference from other ports.

    Thanks,

    -Bobby

  • Thank you for the clarification! This clears up my question as the Clocking Chip is a temporary master, therefore when the port B is not enabled the Clocking Chip will communicate to other chips on its bus 1 with no connection to the main channel.