I am using FRDM-K64F board to record data to SD Card. And I added the USB MSD functionality in the device to access the SDCard through USB. My end device will have provisions to operate with Battery power and/or USB power.
Two questions are
1. When my device is recording the data to SD Card, If I connect to USB Host, I don't want the USB MSD functionality to be active (I can do this by not enabling the USB functionality in the code). However, I don't want USB Host to suspend the USB device, but I'd like to have the Host keeps supplying power without USB device functionality enabled. How can I do that?
2. When my data recording stopped (with USB connected to Host), I can enable K66F USB device MSD functionality. But I'd like to know, how to let the Host knows that USB device is connected without physically unplug and replugging in USB.