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TCA6418E: RESET the IC via I2C - is this possible?

Part Number: TCA6418E
Other Parts Discussed in Thread: TCA6416A, TCA9539

I’ve been reading through a copy of the datasheet (SCPS243 –SEPTEMBER 2012) and I haven’t been able to find the answer to the following question. Could you please answer it or point me to where I can find the answer?

  • Is there any way to reset the part without pulling power if the reset pin is not connected to the system master? Perhaps a register to write? Or maybe just writing all zeros to the registers (the default value for all of the non-reserved registers is zero according to the datasheet)?

Are there any high-GPIO count devices that can be reset via the I2C bus (writing to a register)?  I looked at the TCA6416A and the TCA9539, and I don't see any register that would control the IC in this manner.


  • Hi Mark,

    If you are looking to reset the internal SMBus state machine you can send 9 clock cycles and a stop bit on your I2C bus. This will clear the internal state machine of all the devices that are powered and connected to the bus.

    If you are looking to reset the internal registers of the device then there is no way to do this without doing a power on reset or toggling the reset pin. Through software you could just write the default values to the registers but there is no way to perform an actual reset without the two options above.