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Original question:

HD3SS3220: Verification of expected voltage levels on ADDR, VBUS_DET, DIR

HD3SS3220: Verification of expected voltage levels on DIR

Doron Darmoni
Prodigy 125 points
Part Number: HD3SS3220
Other Parts Discussed in Thread: TIDA-00891

Hi,

  1. What is the voltage level of the DIR pin? in the data sheet 6.1 Absolute Maximum Ratings it says both VDD5+0.3 & VCC33+0.3. in the sections 8.2.x application diagrams it is pulled high to VCC33 while on the reference design (TIDA-00891 ) it is pulled high to 5V_COM. in the HD3SS3220A-DFP-EVM it is pulled to 3.3V
  2. What is the DIR polarity? In the data sheet, section 7.2 Functional Block Diagram it shows DIR=0 Tx2/Rx2 as well in the section 7.6.3 Connection Status and Control Register bit 5 description while section 7.3.4 Cable Orientation and Mux Control says : "When a voltage level within the proper threshold is detected on CC1, the DIR pin is pulled low "

Thank you

Doron

  • 0
    TI__Intellectual 1350 points
    Hello Doron,

    1. The low level is specified to be 0.4V, so voltages above that level should be fine. This is why the TI design and EVM both work even though they are pulled up to 5V or 3.3V respectively. The the recommended pull-up resistor is 200k. Ensure the voltage at the pin does not exceed VCC33+0.3V, which the easiest way to do would be to pull up to VCC33.

    2. The polarity of DIR is active high.

    Best,
    Gerasimos
  • 0 in reply to Gerasimos Madalvanos66
    Prodigy 125 points
    Hello,
    1. Sorry, I didn't understand the answer- Is the DIR signal is 3.3V or 5V?
    According to your answer- Ensure the voltage at the pin does not exceed VCC33+0.3V what happens if i pull it to 5V? It will exceed the VCC33+0.3V...
    2. Sorry, I didn't understand the answer again- what do you mean DIR is active high? low=? High=?
    Which indicates CC1/Tx1/Rx1?
    Which indicates CC2/Tx2/Rx2?

    Thank you,
    Doron
  • 0 in reply to Doron Darmoni
    TI__Intellectual 1350 points

    Hello Doron,

    1. DIR signal is VCC33. If you pull it up to 5V the voltage at the pin  will not necessarily be 5V. Because this pin is open drain, when the pin is not driven low, it will function as a voltage divider between the pull up resistor and the open drain of the pin. With a sufficiently large voltage drop over the first resistor, the voltage at the pin will still be 3.3V even when pulled up to 5V. 

    2. CC1/Tx1/Rx1 is when DIR is 3.3V or logic level 1. CC2/Tx2/Rx2 is when DIR is 0V or when DIR is logic level 0.

    Hope this helps!

    Best,
    Gerasimos 

  • 0 in reply to Gerasimos Madalvanos66
    Prodigy 125 points

    Hello Gerasimos ,

    it help a lot thank you very much.

    should fix the data sheet i think.

    Doron