Detecting a USB Disconnection imx1050

[nick_j]

Hello,

I am trying to detect when a USB is disconnected from my custom board using an imxRT1050. I have seen other forum posts that mention to use the USB_DEVICE_CONFIG_DETACH_ENABLE flag in the USB device config (https://community.nxp.com/t5/i-MX-RT/What-is-the-best-way-to-detect-attaching-and-detaching-of-an-us...).

Looking at the USB_1OTGSC register it does show that the BSVIE (B Session Valid Interrupt Enable) has been set, however the interrupt doesn't seem to trigger. I know this as I will get interrupts when I plug the USB in, but not get one when I pull it out. 

The only way I've managed to detect it is by polling the SUSP (Suspend) bit within the USB_1PORTSC1 register the tells me whether or not the connection is suspended. I should be able to get this to work. but I would rather use the dedicated disconnection interrupt as it doesn't involve polling the register.

Any ideas as to why the B Session End Interrupt may not be triggering?

Thanks,

Nick

[Kan_Li]

Hi @nick_j ,

Do you mean you are using the USB stack from the latest SDK with the solution of https://community.nxp.com/t5/i-MX-RT/What-is-the-best-way-to-detect-attaching-and-detaching-of-an-us... , but it doesn't work? Please kindly clarify.

Best Regards,

Kan

[nick_j]

Hi Kan,

I'm not using the most recent SDK, but I definitely downloaded it after this post was made. I will try the latest however just in case.

What I'm expecting is that I will receive a USB interrupt when the USB is disconnected/unplugged once I have implemented the suggestion in the linked forum post. However this does not happen and I can't understand why as I am receiving interrupts for other USB events.

Thanks,

Nick

[Kan_Li]

Hi @nick_j ,

There is wake up on disconnect event for this use case, please kindly refer to the following for details.

You may refer to "42.4.3.2 Wake-Up Events" in https://www.nxp.com/webapp/Download?colCode=IMXRT1050RM for more details.

Have a great day,
Kan

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