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Windows 10 PC and USB CDC ACM Device PC Side Driver Timeout Issue

Latest Updated:09/15/2016

Question:

I'm seeing a Windows 10 PC USB timeout issue with my Synergy USB CDC ACM device. Any idea what it is?

Answer:

Using USBView on a windows 10 PC that exhibits the CDC ACM timeout issue, USBView reports an error with the device descriptors as seen below.

default_descriptors.jpg

The descriptors show as a problem on all PC's, with the latest version of USBView. However, this doesn't cause an issue on windows 7 machines, and not all Windows 10 machines. When the problem occurs, the COM port appears to have been created, but the terminal program cannot open the port,and then eventually in device manager, the USB COM port shows an error.

The file to edit/replace is src/sf_el_comms_port.h in a project that uses the UX comms framework.

sf_el_ux_comms_port.h

After modifying the device descriptors to fix these problems reported by USBView the CDC ACM worked correctly on the PC that exhibited the timeout issue, using the default windows 10 in box driver.

jb_descriptors.jpg

Suitable Products
Synergy USB CDC ACM