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TCA6416A: Can the I/O ports be configured to power up in Hiz state

steve smith1
Intellectual 340 points
Part Number: TCA6416A
Other Parts Discussed in Thread: TCA9555

Tool/software:

Hi I am using 2x TCA6416A as a controllers for my board but it would be useful as a debug tool if I could manually pull these lines high or low to check out the rest of the board while IIC firmware is being written.

Is it possible to set this part so the outputs default to Hiz on power-up (unless commanded  high/low by the IIC bus) ? If so I could have a single header pin on each I/O which could be used to apply high/low and also double as a test point. (currently using 3 pin headers per line to serve a changeover function but this takes up too much board space.)

Best,

Steve

  • 0
    Guru 316470 points

    The default configuration of all pins after power up is as input, i.e., they are Hi-Z.

  • 0
    TI__Mastermind 47008 points

    Hi Steve,

    As Clemens suggested, the default configuration after power up is high impedance inputs. There is no way to program the device to power up differently. 

    Would something like TCA9555 work for your application? It has slightly different pinouts for the address and /reset pins, but TCA9555 has internal 100k pull-up resistors built into the device. The device would power up with high-z inputs pulled HIGH to VCC through the internal 100k pull-up resistors. Not sure if this would help, but it is an option that could work. 

    Regards,

    Tyler

  • +1 in reply to Tyler Townsend
    Intellectual 340 points

    Hi Tyler, Clemens, thanks for the info. Hiz input on power-up is just perfect. This means if the IIC isn't addressed we can externally drive the circuit (oV, 3.3V) to which the I/O pin is connected to test without risking damage to your part.