TCA8418: Operation immediately after power-on

Part Number: TCA8418

Tool/software:

Hi team,

With the reset pin set to “H”, the output goes High when the power is turned on.
I have an LED connected to 13-pin COL4 and it lights up momentarily.
It turns off when the register setting by I2C is completed.
Is this a specification?

Best Regards,
Ryu.

  • Ryu,

    I think this has to do with default value of the GPIO pull-up disable register. 

    The internal pull-up resistors are enabled at power up since the default value of these registers is "0" which will enable the internal pull-up resistors. I assume based off your problem that the pin 13 COL4 is connected to the anode of the LED. Please correct me if I am wrong here. 

    Regards,

    Tyler