Forgive me if the title is in the form of an XY Problem, but:
I have a Windows system with a lot of USB devices hanging off of it. (I'm an embedded developer with a bunch of clients, and as often as not, need to run longitudinal tests on a bunch of embedded devices.) I observe the following phenomenon:
My default set of USB devices looks like this:
However in this case, my OSBOT TinyCam device is unavailable. ("It looks like another app is using the camera already. Windows Camera app error code 0xA00F4243")
If I eject (or just unplug) ANY four of the EDBG CMSIS-DAP devices and/or Atmel-ICE CMSIS-DAP devices, the TinyCam performs normally.
Which leads me to the questions:
- Is there a limit to the number of devices the system can manage on the USB bus?
- Is there additional information I can collect to better diagnose the problem?
Also, I don't believe this is specific to the OSBOT TinyCam. For example, if I unplug all the CMSIS-DAP USB devices and plug in the OSBOT TinyCam and launch the Camera app, the camera works fine. But then if I plug in all the CMSIS-DAP devices AFTER plugging in the TinyCam, my Microchip IDE can no longer access all the CMSIS-DAP devices:
So in this case, it looks like "whoever gets there first" is the one that works, and others are excluded.