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TCA9543A: Can the device reset by SMBus command

Jim Tsai
Expert 4470 points
Part Number: TCA9543A

Hi,

Can I reset TCA9543 via SMBUS command ?

Please refer to below snapshot , the command I marked shows reset default state , does it mean we can use this command to reset TCA9543A?

  • 0
    TI__Mastermind 26546 points

    Jim,

    Thanks for reaching out! The TCA9543A can be reset in either of two ways:

    • RESET input - active-low digital input that resets the device. (See datasheet section 8.4.1)
    • Power-on reset (POR) - cycling the power supply VCC. (See datasheet section 8.4.2)

    These allow the device to be reset in case of a stuck bus situation. The datasheet section you included indicates that the value of the control register will be 0x00 upon startup or after one of these reset cases. This means that triggering a reset closes both channels, and none will be selected.

    There is not a way to formally reset the device via a command over SDA/SCL, but you can achieve the same state by turning off both channels to achieve 0x00 in the control register.

    When using the reset functionality, many times, this is done due to a stuck bus that is preventing communication, which would render a reset command via the bus effectively powerless. The RESET pin and the POR both would override the status of the bus.

    Best,

    Danny