Hi,
I would like to know the behavior of the USB OTG module for AM3874.
My customer uses USB OTG module of AM3874 as host. For this reason, they connect USBx_ID pin to Ground. This means AM3874 USB roles as A device (host).
But, in this setting, bit 7 of Device control register changes frequently. Please see the below figure.
I know IDDIG bit of USB Mode register will override the ID sense value and force the controller to operate as the USB Host or a USB Device.
So the OTG module can be changed even though USB_ID pin is set as host.
But I don't know why USB module changes the role A device - B device frequently. Is this behavior normal action by USB driver?
Also my customer says, AM3874 OTG module always become to be as B device when the USB memory is inserted to AM3874 system. And after that, OTG module become to be as A device(host) even though USB_ID pin is always pulled down. Is this behavior also by USB driver?
Please let me know.
Best regards,
Michi