This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCD3138: Default mode on each pin when POR

Part Number: UCD3138

Hi Team

I have a question with regards to our UCD3138. 

Are all the ucd3138’s pins (not include ADC/BP18/RESET/Vss/VDD/EAP) configured to input mode during power on reset? 

For example:

                              Pin 12 is Open Drain. So it is float mode. But how about DPWM0A? Does it float mode also?

 Thanks! 

Best Regards,

Alfred

  • Can you confirm that the below table is correct for the pins initial state at power on reset?

  • I don't know where you got those last charts.  I hope it's not a TI document, as it has some issues, for example all DPWMs are always low after reset.

    It's a bit more complicated, because on some devices, all GPIO pins are pulled low during reset, and then released when reset is releases.  Other devices the GPIO pins float during and after reset.  Of course, before the 3.3 volt supply reaches an acceptable level, they are indeterminate.  

    Here is a table for all the devices:

     

    I/O type

    UCD3138 and UCD3138064

    UCD3138A64, UCD3138128, UCD3138A, UCD3138064A, UCD3138A64A, UCD3138128A

    Undefined IReset*

     

    (V33D < Vres)

    IReset Low*

    IReset high*

    Undefined IReset*

     

    (V33D < Vres)

    IReset Low*

    IReset high*

    GPIO (Push-Pull)

    Not high Impedance (Pulled low by ESD diode)

    High Impedance

    High Impedance input as default

    Not high Impedance (Pulled low by ESD diode)

    Pulled low

    High Impedance input as default

    GPIO (Open Drain)

    High Impedance

    High Impedance

    High Impedance input as default

    High Impedance

    Pulled low

    High Impedance input as default

    DPWM

    Not high Impedance (Pulled low by ESD diode)

    Output low as default

    Output low as default

    Not high Impedance (Pulled low by ESD diode)

    Pulled low

    Output low as default

    Analog Input

    Not high Impedance (Pulled low by ESD diode)

    High Impedance

    High Impedance

    Not high Impedance (Pulled low by ESD diode)

    High Impedance

    High Impedance

    * For definition of IReset please see drawing below

     

    Note that Ireset actually is low when the external reset pin is low, not high.  So if the reset pin is held low, most of the devices will pull their GPIO pins low as well.  

  • This has been sitting here forever.  I'm going to assume it is resolved.