USB hub multiple devices connection issue

[Gangapavan]

I am using an i.MX RT1060 controller in my project development. I am facing issues with USB hub functionality when multiple devices (MSD — pen drive, and CDC — printer) are connected in the following sequence:

Case 1

A) Printer: Attach event occurred and working fine

B) Flash drive: 

• No attach event is triggered for the flash drive.

• When the flash drive is removed, the system hangs inside USB_HostReleaseDeviceResource.

Case 2

A) Flash drive: Connected and working

B) Printer: Attach event occuured, but full interface is not properly completed. It returned error in some port open event call back.

• When the flash drive is removed, both devices got disconnected.

Case 3

• Both flash drive and printer inserted: Only the flash drive attach event occurred and working.

• When the flash drive is removed and reconnected, it works fine.

• CDC device connection/disconnection generates no event.

• The only way to recover CDC functionality is to restart the system.

Findings:

When I connect the hub to a PC to verify its functionality, both devices are visible in Device Manager. Based on this, I conclude that the issue lies in the USB driver implementation /Composite device handling for USB on the i.MX RT1060.

Is there a way to handle this issue so that both MSD and CDC devices can be reliably enumerated and managed through the hub?

Regards,

Pavan

#IMXRT1060 #nxp #Microcontroller #USB Hub #USB Composite device handling.