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Azure RTOS STM327H73 BIT 6 connected to USB2514 UB connections are flaky

Associate III

We are having a bear of a time getting the USB2514 to work properly with the STM327H73 both with the USB2514 built into our board and also with the STM327H73 connected to a EVB-USB2514BCQFM36 eval board. Looking for suggestions for resolving this issue, suggestions sample github code anything really.

We have a custom board with a STM327H73 USB port is connected to  the USB eval board. System is running Azure RTOS 6.1 and USBX.

  1. USBX is initialized 
  2. USBX stack as a HUB, CDC ACM host classes registered (HID and Storage  host classes also but not used for this test)

Here's the symptom.

  1. Boot the system with a CDC ACM serial port connected, CDC ACM port is recognized and works as expected
  2. if step one did not have a CDC ACM serial port connected connect it after booting. CDC ACM port works as expected
  3. disconnect the CDC ACM port, port disconnects as expected.
  4. From this point on the USB2514 hub will not recognize anything being plugged into any of the 4 ports
  5. For grins the USB2514 USB cable was unplugged, USB hub device removed as expected.
  6. USB 2514 was plugged back into the STM327H73 USB and the USB HUB was recognized
  7. Proceed to step 1

Any thoughts on how unplugging a CDC ACM port would render the USB2514 HUB useless until it it forcefully reset again?

Associate III

Interestingly noticed that if the call to 

if (ux_host_stack_class_register(_ux_system_host_class_cdc_acm_name, ux_host_class_cdc_acm_entry) != UX_SUCCESS)

is removed and usb start time, the serial port can be plugged and unplugged many times. The serial port will not enumerate, because the usb stack does not know what the serial port is. Anybody else running into generic USBx cdc acm resource issues causing serial ports not to be usable after the first discovery?