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the problem for Vbus Error for BF526?

Question asked by xuyejin@sina.com on Feb 21, 2015
Latest reply on Feb 26, 2015 by xuyejin@sina.com

HI.

   I am using BF526 processor to develop USB OTG Host for my embeded application on VisualDSP++5.0 with update 10.0.

   why the  bits VBUS1-0 in USB_OTG_DEV_CTLcan not be 11?

   when I run to DriveVbusOn(),then the software loop on line

   while( (*pUSB_OTG_DEV_CTL&0x0018)!=0x0018) ;

 

   then when I modify the line as follow

   while( (*pUSB_OTG_DEV_CTL&0x0018)>0x0008) ;

 

   when I inserted USB flash disk, insert breakpoint in static ADI_INT_HANDLER_RESULT UsbInterruptHandler().

   It always happen VBUS error interrupt.

   QQ图片20150222103353.png

    the  bits VBUS1-0 in USB_OTG_DEV_CTL is 00

     QQ图片20150222103446.png

  the  bits VBUS1-0 in USB_OTG_DEV_CTL is 10

       QQ图片20150222104347.png

      set session bit the  bits VBUS1-0 in USB_OTG_DEV_CTL is 01,detect USB-PID is low.

   QQ图片20150222104522.png

     the  bits VBUS1-0 in USB_OTG_DEV_CTL is 10  ,and generate vbus error interrupt USB_INTRUSB is 0x80

    

I measured the voltage on Vbus is 4.87V. the threshhold for Vbus valid is what?

why the error happened?

 

regards.

yejin xu

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