Why the usb OTG controller can't get the SLI interrupt when usb device is connected to USB1.1 host

[liuxing]

Hi all,

    when I make the USB OTG Port of IMX28 as device mode and connect to USB1.1 Host,It can't get the "DC Suspend" interrupt when I remove usb cable.However,This test work well when the usb device is connected to USB 2.0 Host.

     some register value of usb controller is as follows:  

    USB 2.0    test

Before removing usb cable
0x08200E20(HW_USBCTRL_OTGSC),  0x18000205(HW_USBCTRL_PORTSC1),0x00000080(HW_USBCTRL_USBSTS)

  After removing usb cable,and can get interrupt

0x08202E20(HW_USBCTRL_OTGSC), 0x18000A85(HW_USBCTRL_PORTSC1), 0x00000180(HW_USBCTRL_USBSTS)

USB1.1 test

Before removing usb cable

0x08202E20(HW_USBCTRL_OTGSC),0x10000805(HW_USBCTRL_PORTSC1), 0x00010080(HW_USBCTRL_USBSTS)

  After removing usb cable,and can't get interrupt

[b36401]

You can refer chapter 2.2.2.1 "5-V detection methods" of Using the i.MX28 Power Management Unit and Battery Charger application note I attached regarding to DC Suspend interrupt.

Have a great day,

Victor

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[liuxing]

   Thanks a lot!

    However,I think you misunderstand my question.I only need to know how to make the usb OTG controller enter DC suspend mode when I remove the USB cable.And The I.MX28 CPU will be active at that time.if the usb device is connected to USB1.1 HUB,it can't get SLI interrupt when usb cable is removed.I think it's the root cause of this issue.This issue can be reproduced by several Hardware platform.

   This issue is very urgent for us.It can be accepted if you can provide workaround at present.