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TUSB422: Inquiries related to communication

Part Number: TUSB422

Hi, TI support team

The TUSB422 is being reviewed by designing the circuit as shown below.

(I2C SCL/SDA, INT pins have 1.8V pull-up.)

I2C address is set as specified in the datasheet, but it is confirmed that the Ack signal does not come.

Check the circuit diagram and waveform for any errors.




  • is I2C address 20?

    did you following this power on sequene?



  • Hi, Brian

    1. I2C Address : 0x20 is set

    A. I tried changing the address from 0x00 to 0xFF just in case, but it didn't work.

    2. Power On sequence: Refer to the measured waveform below

    A. In the datasheet, TINT_N_LOW is Max 4ms, and the measured value is 1.5ms, which seems to be spec in.


    C. The VCONN pin was not used in UFP mode, so it was left floating (refer to the circuit diagram in the previous mail), and I tried to connect it to the VDD pin

    just in case, but the symptoms are the same.

    D. The waveform below is the power on sequence taken with the VDD pin and VCONN pin connected.

    There seems to be no problem with the power on sequence.

    Please review if there are any other causes.

    It is a process for the customer to check whether I2C communication is normally performed, not the entire operation of the product.

    Are there any register settings that are essential for normal I2C communication?

    So far, we have tested by referring to page 19 (7.5 Programming) of the datasheet.

    Please confirm.




  • are there any other device use 0X20 as well?