Tool/software:
Hello,
I wonder if the USB3.0 data lines between [a PC and the TUSB8042A] or between [the TUSB8042A and a downstream device] can cross or not?
1) Can you tell me which are the correct connection cases in the following four propositions:
Case n°1:
D+ --> D+
D- --> D-
SSTX+ --> SSTX+
SSTX- --> SSTX-
SSRX+ --> SSRX+
SSRX- --> SSRX-
* No crossing in the data lines.
Case n°2:
D+ --> D-
D- --> D+
SSTX+ --> SSTX+
SSTX- --> SSTX-
SSRX+ --> SSRX+
SSRX- --> SSRX-
* The D+ and D- lines are crossed.
Case n°3:
D+ --> D+
D- --> D-
SSTX+ --> SSRX+
SSTX- --> SSRX-
SSRX+ --> SSTX+
SSRX- --> SSTX-
* The TX and RX lines are crossed with the same polarity.
Case n°4:
D+ --> D+
D- --> D-
SSTX+ --> SSRX-
SSTX- --> SSRX+
SSRX+ --> SSTX+
SSRX- --> SSTX-
* The TX and RX lines are crossed with the same polarity for one differential pair and a different polarity for the other differential pair.
2) Is it mandatory to cross the polarities of the two differential pairs or can the polarity be changed only on one?
3) There are cables that cross the TX differential pairs with the RX differential pairs. Is this a problem or should we use non-crossed cables?
Thank you in advance for your help and explanations.
Best regards,
Rob
