Re: 8-ch audio card USB Bus Problems
Posted: Thu Mar 29, 2018 12:48 pm
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1) Consider to open a support ticket with XMOS for their review of your design against the applied CPU package.
2) Can you post an updated schematic and PCB layout for this design? Or forward via PM is ok.
3) What are the details of your USB cable? Is the USB cable certified for HS (480 Mbps) use? Keep the cable short as possible and try to source from a branded make of the cable. For example, Belkin USB 2.0 cable. There are differences in the quality of the cables. Do test with other cables.
4) Are your voltages stable on the power supply? Clocks are stable? 5 volts solid? 3v3 ? 1v0? Since you have a buck boost from the USB to your product, you could consider to power the board using a known good external power supply @ 5 volts (bypass the buck boost) for testing. Of course, do not feed the external 5v0 back to the host PC!!
5) From this thread, USB HS (480 mbps) is not reliable but this version of the PCB enumerates ok? What PC ports have been tested? Can you test with other PCs? Test with ports with the black insulator only (USB 2.0 ports) and not USB 3.0 (Blue insulator) for now.
6) Do you have access to a USB bus analyzer?
7) Not that you have much between the USB connector and the XMOS device but can you remove the EMI filter and just bypass with a clean piece of solder for each track and test again?
8) From the original schematic, how is 3.3PG generated? Could not locate the source, at least one the last review.
9) Is R109 = 4R7 ohms? (4.7 ohms)
10) XMOS has some USB CDC / HID model IP posted. Consider to upload this onto this board to check on the stability of their IP.
11) Is the end result that you have enumeration faults? Are the results the same on Windows and Linux platforms?
Post your results.
1) Consider to open a support ticket with XMOS for their review of your design against the applied CPU package.
2) Can you post an updated schematic and PCB layout for this design? Or forward via PM is ok.
3) What are the details of your USB cable? Is the USB cable certified for HS (480 Mbps) use? Keep the cable short as possible and try to source from a branded make of the cable. For example, Belkin USB 2.0 cable. There are differences in the quality of the cables. Do test with other cables.
4) Are your voltages stable on the power supply? Clocks are stable? 5 volts solid? 3v3 ? 1v0? Since you have a buck boost from the USB to your product, you could consider to power the board using a known good external power supply @ 5 volts (bypass the buck boost) for testing. Of course, do not feed the external 5v0 back to the host PC!!
5) From this thread, USB HS (480 mbps) is not reliable but this version of the PCB enumerates ok? What PC ports have been tested? Can you test with other PCs? Test with ports with the black insulator only (USB 2.0 ports) and not USB 3.0 (Blue insulator) for now.
6) Do you have access to a USB bus analyzer?
7) Not that you have much between the USB connector and the XMOS device but can you remove the EMI filter and just bypass with a clean piece of solder for each track and test again?
8) From the original schematic, how is 3.3PG generated? Could not locate the source, at least one the last review.
9) Is R109 = 4R7 ohms? (4.7 ohms)
10) XMOS has some USB CDC / HID model IP posted. Consider to upload this onto this board to check on the stability of their IP.
11) Is the end result that you have enumeration faults? Are the results the same on Windows and Linux platforms?
Post your results.