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TUSB322I: plus TUSB542 for CC pin question??

David lin
Prodigy 135 points
Part Number: TUSB322I
Other Parts Discussed in Thread: TUSB542, TUSB322

Hi
we use TUSB542 plus TUSB322i for our new project
who have design quesiton would like to ask you,
the Figre 16 of Datasheet on TUSB542
it highligth connnection flip for CC1 and CC2
as my understand, does SEL pin of TUSB542 have different behavior
with DIR pin of TUSB322i, therefore we
tied SEL pin to DIR pin directly, we must to flip for CC1 and CC2,
is it right, we would like to flip CC1 and CC2, as below is our purpose design, could you give us some suggestion??
is it not, could you explain for more detail why connection flip for CC1 and CC2??

[our purpose design#1]don't flip for CC1 and CC2
TX_RX Conn_1(TUSB542 pin2,3,6,7) -->Conn Position 2
TX_RX Conn_2(TUSB542 pin8,9,11,12)-->Conn Position 1

[our purpose design#2]don't flip for CC1 and CC2
refere circuit as below

[Figre 16 of Datasheet on TUSB542]flip for CC1 and CC2
TX_RX Conn_1(TUSB542 pin2,3,6,7) -->Conn Position 1
TX_RX Conn_2(TUSB542 pin8,9,11,12)-->Conn Position 2
SEL pin of TUSB542
H (Conn Position 1)
L (Conn Position 2)

DIR pin of TUSB322i:
H (Conn Position 2)
L (Conn Position 1)

Sincerely

David

  • 0
    TI__Guru**** 179981 points

    David

    As you pointed out in your question. The polarity of SEL pin is different from the polarity of the DIR pin.

    SEL pin of TUSB542
    H (Conn Position 1)
    L (Conn Position 2)

    DIR pin of TUSB322i:
    H (Conn Position 2)
    L (Conn Position 1)

    In order to connect directly between the TUSB542 SEL pin and TUSB322 DIR pin, you would have to flip CC1/2 as shown in Figure 16 of the TUSB542 datasheet.

    Purpose design #1 would work. But from PCB layout consideration, it would easier to route CC1/2 than the 5G SuperSpeed signals. 

    Purpose design #2 would also work as you are using the MOSFET as an inverter. 

    Thanks

    David

  • 0
    TI__Guru 64326 points

    Hi David,

    If I understand correctly you would like to flip connection the CC1 and CC2 connection to TUSB322I. This should not be done. CC1 should be connected to CC1. CC2 should be connected to CC2. This is critical to the TUSB322I internal state machine to ensure correct orientation of the connector is determined. If you are trying to eliminate the "switch" in the reference schematic I would recommend flipping CON1 and CON2 connections. 

  • 0
    Prodigy 135 points

    Hi All

    could you help me review schematic ??

    if so,  i will send to you by mail

    Thanks.

    David

  • 0 in reply to David lin
    TI__Guru**** 179981 points

    David

    Please accept my friendship request and you can then send me the schematic through private message.

    Thanks

    David