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TUSB321AI: The CC issue for TUSB321AIRWBR

Zhang Liang
Genius 5035 points

Part Number: TUSB321AI
Other Parts Discussed in Thread: HD3SS3212, TUSB321

Hi,

Our design is: 

USB 3.0 communication requires two sets of TX and RX differential pairs. But our ARM can only provide one set of TX and RX. Therefore, we use TI's TUSB321AIRWBR and HD3SS3212IRKSR to achieve this function.
 
1. For TUSB321AIRWBR, the CC1, CC2 inside the chip and the CC1, CC2 on TYPE-C are staggered, rather than corresponding one-to-one:
900ca8d8332b1baf4b6d89ca9cddd8c2.jpg
f9bbcad58af90589d9b037a858bd60fa.jpg
2. The 900K on the VBUS_deT pin needs to be NC dropped, If 900k does not drop, the status of CC1, CC2, and DIR will be incorrect:
cbcddde3137e96e65a70b5ba45f801f1.jpg
 
  • 0
    TI__Guru 52750 points

    Hello,

    Zhang Liang said:
    1. For TUSB321AIRWBR, the CC1, CC2 inside the chip and the CC1, CC2 on TYPE-C are staggered, rather than corresponding one-to-one:

    For using the TUSB321AI with the HD3SS3212, CC1 and CC2 should be swapped per the typical application in the TUSB321AI datasheet:

    Zhang Liang said:
    2. The 900K on the VBUS_deT pin needs to be NC dropped, If 900k does not drop, the status of CC1, CC2, and DIR will be incorrect:

    How is the TUSB321AI being used, as a DFP, UFP, or DRP?

    If being used as a UFP or DRP, the VBUS_DET pin must be pulled up to VBUS with a 900KOhm resistor, or else TUSB321 will not be able to configure as a UFP.

    Additionally, for a DFP application, please ensure that the ID pin is being used with a power switch or something similar to control when VBUS is being sent to the type-C connector. If VBUS is not controlled by the ID pin, the type-C connection will either work in only one orientation or will only work in USB2.

    Thanks,

    Ryan