Dear Forum,
i have a question about a extraordinary constellation of a USB-Routing with two USB-Switches (TS3USB221ERSER).
Please see follow picture in attachment.
I got one answer from the Ti Support directly yet, that i can leave 2D from U1 open to floating.
What about the connection between the USB-Device and the both Switches U1 (1D) and U2 (2D). Does it work ? Or do we get a impedance problem ? Of course both switches are placed on layout that we get very quick tracks on the PCB (U1 on Top-Layer, U2 on Bottom-Layer).
Both Switches don't work on the same time. The control signals for S and especially nOE from both switches have the constellation that either U1 or U2 is enabled.
The problem is, that we cannot get a link through U1 to the USB-Device. Through U2 the link to the MCU is working perfect and we can flash it.
If we get a physically link i cannot tell. Cause my second question is, if it is possible to look with a multimeter as a continuity checker in operating mode? Or do we get a problem ? The checker is working with 3.3V.
I cannot find any reason in the datasheet. So can you give me some advices or ideas ?
Thanks and regards.
Wolfgang Walter
