Dear Expert
We base on QC reference design add TUSB544 for USB type-C redriver as source mode, for now the USB3.0 work but DP didn't.
We had check the DP signal is OK from QC source, but when we use differencial probe measure 4 lane TUSB544 output, there are no any differencial signal when it be DP mode.
My customer's old design without TUSB544( on a little daughter board ) can work Display port but in new design with TUSB544 on that daughtor board, DP can't work for the same main board.
After check spec, I found in 7.3.2 DisplayPort describe, it seems means AUXs and SBUs need to connect through TUSB544.
But in our schematics, we make AUXN/P and SBU1/2 pins be floating because QC IC have SBU MUX in SOC. And we are sure SBU signal is OK for system output.
Would this design make TUSB544 can't monitor the lanes signal and make redirver channel all off ?
My question is that if we don't use TUSB544 AUXN/P and SBU1/2, can we left those pin floating at Display Port GPIO control mode?
Please help! Thanks!
BR
Bruce
following are describe in 7.3.2
monitors the native AUX traffic as it traverses between DisplayPort source and DisplayPort sink. For the purposes of reducing power, the TUSB544 will manage the number of active
DisplayPort lanes based on the content of the AUX transactions.
