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Original question:

TUSB212: TUSB211-Q1 DP and DM swap

TUSB212: DP and DM swap didn't work

Yoshikazu Kawasaki
Expert 3510 points
Part Number: TUSB212

Hello,

This is related to another post in E2E shown below saying DP and DM can be swapped for TUSB212-Q1 as well, but my customer confirmed it didn't do as shown in the post.  It worked neither DC nor AC boost, but did if they corrected the path between TUSB212-Q1 and Host/Device, DP to DP and DM to DM.  Does it require external parts or something to make it work by swapping DP and DM?  If it doesn't, what would be the reason why my customer's system didn't work?

This path didn't work.

                                            TUSB212

DP(Host)--------------------D1M---D2M-------------------DP (Device)

DM(Host)--------------------D1P---D2P-------------------DM (Device)

This path worked.

                                            TUSB212

DP(Host)--------------------D1P---D2P-------------------DP (Device)

DM(Host)--------------------D1M---D2M-------------------DM (Device)

Best Regards,

Yoshikazu Kawasaki

  • 0
    TI__Guru 64326 points

    Hi Kawasaki-san,

    Customer is seeing the expected behavior, USB 2 polarity cannot be swapped with TUSB212. The D1x and D2x sides of the device can be swapped with issue assuming polarity is conserved (DP->DP and DM->DM). TUSB212 uses DM specifically to understand if HS terminations have been enabled by USB Host and Device, if so, TUSB212 turns on AC and DC boost. If TUSB212 DxM pin is connected to DP this function cannot occur and boost function will not be enabled.