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HD3SS3220: Using HD3SS3220 as switch in UPF mode.

Igor Gavrilenko
Prodigy 50 points
Part Number: HD3SS3220


We would like to use HD3SS3220 as high speed switch.

1. Is it enough if we connect to the CC lines logic signals from FPGA to control SS MUX?

2. What is sequence of CC lines to change MUX state.

3. Does pin:12 EN_MUX disconnect all SS signals in high state?

  • 0
    TI__Guru**** 181321 points
    Igor

    Would you please give more detail on your design requirement? Is this a USB3 design?

    When EN_MUX is high, it will disable the HD3SS3220 output.

    There are multiple modes depending on the state of CC1 and CC2. Table 1 summarizes these modes. For more detail, please refer to USB3 Type C spec.

    Thanks
    David
  • 0 in reply to David (ASIC) Liu
    Prodigy 50 points

    David,

    We want connect to our product SSD disk or Ethernet controller via USB3. See picture.

    As I understood we need connect one of CC pin via resistors 4.7k-36k to 3.3 V and switch will change a channel. Does HD3SS3220 use passive analog switch and do not checks RX/TX signals?

    We tried to change logic levels on the CC (CC1 = LOW, CC2=HIGH and CC1 = HIGH, CC2=LOW) pins but switch did not change channel. May be need special sequence for CC to control MUX?

    Thanks

    Igor 

  • 0 in reply to Igor Gavrilenko
    TI__Guru**** 181321 points
    Igor

    HD3SS3220 supports passive switch.

    The HD3SS3220 detects the cable orientation by monitoring the voltage on the CC pins. When a voltage level within the proper threshold is detected on CC1, the DIR pin is pulled low. When a voltage level within the proper threshold is detected on CC2, the DIR is high. The DIR pin is an open drain output and a pull-up resistor must be installed. The cable orientation status is also be communicated by I2C for HD3SS3220. Are you seeing the DIR pin toggling when you are changing the CC1/CC2 voltage?

    Are you configuring HD3SS3220 as UFP, DRP, or DFP?

    Thanks
    David
  • 0 in reply to David (ASIC) Liu
    Prodigy 50 points

    David,

    We use UFP mode. We use the same schematic for PC connection and it work without problem. But if we try to control switch from our signals then it does not work and DIR pin does not toggle. What voltage level need to set on the CC pin to switch MUX? Is it possible to use DIR pin instead CC to manage MUX?

    Thanks

    Igor

  • 0 in reply to Igor Gavrilenko
    TI__Guru**** 181321 points
    Igor

    The 5.1k resistor is present inside the HD3SS3220, you don't need external resistor.

    Please refer to the HD3SS3220 V(ufp_cc_usb), V(ufp_cc_med), and V(ufp_cc_high) voltage level. The voltage on CC1 or CC2 depends on current capability advertised by the DFP.

    Can you please share your schematic?

    Thanks
    David
  • 0 in reply to David (ASIC) Liu
    Prodigy 50 points

    David,

    See our schematic below.

     

    A am sorry but I have not time to investigate problem. I will investigate in future but we change HD3SS3220 to simple MUX now. Thank you for support.

    Best regards, Igor

  • 0 in reply to Igor Gavrilenko
    TI__Guru**** 181321 points
    Igor

    Understand. Looking at the schematic.

    INT/OUT3 needs to be pulled up through 200k resistor
    CURRENT_MODE don't care in UFP, leave it floating
    No resistor on CC1 and CC2.

    I will close this thread for now, please feel free to reach out to me if you want to look at it again.

    Thanks
    David