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.
the bits VBUS1-0 in USB_OTG_DEV_CTL is 00
the bits VBUS1-0 in USB_OTG_DEV_CTL is 10
set session bit the bits VBUS1-0 in USB_OTG_DEV_CTL is 01,detect USB-PID is low.
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?