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TCA9548A: Need to restart the Esp32 board in order for the Multiplexer to detect the sensors.

Matias Bel
Prodigy 10 points
Part Number: TCA9548A

Hi, I need to restart the Esp32 board for the multiplexer to register the sensors, if i plug at first boot the TCA9548A dont recognize the sernsors, but if I hit the reset in the ESP32 it recognize them.
I tryed using the internal TCA9548A reset pin connecting it to ground, it stops the functioning of the TCA9548A but it still dont recognize the sensors, only with main board reset im able to recognize them.

The sensor Im using is Adxl345, this is the TCA9548A module im using, , have tried with another main board like arduino uno, and the same issue happened.

Wait for your response.

Thanks!

  • 0
    Guru 316920 points

    The TCA9548A is a passive switch and does not recognize anything. It does not have any internal memory, except for the single control register that enables/disables the slave channels.

    Apparently, the problem is that the software on your ESP32 and Arduino boards does not correctly re-scan the bus to find new devices.

  • +1
    TI__Mastermind 47748 points

    Hi Matias,

    This sounds like an implementation issue by the ESP32 or Arduino. The TCA9548A (like Clemens suggested) is a passive I2C controlled switch. The only time this device is actively driving the I2C SDA line is when an ACK bit is issued from a correct exchange of data to the device to enabled/disable I2C channels (all of which are default disabled). 

    Matias Bel said:
    I tryed using the internal TCA9548A reset pin connecting it to ground, it stops the functioning of the TCA9548A but it still dont recognize the sensors, only with main board reset im able to recognize them.

    Its possible that communication is not reaching the TCA9548A correctly. Do you have a scope capture of the I2C read out to the TCA9548A? SDA/SCL channels. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    Prodigy 10 points

    Thanks for the reply, currently solved the issue reseting the esp32 board internaly by software, this bypasses the problem, and since is not an important proyect will keep this solution, anyway appreciated your help!

    Thanks!