Assuming I'm able to get MFI approval for a project. hypothetically of course I want to know if there is any way to read/query a USB-connected iOS device for its battery percentage/charging status WITHOUT needing to have an special app installed on the iOS device. At the opposite end of the line, I want to retrieve this information serially on a micro controller through a UART. Is this type of request supported at such a low level?
Much of the information in the UIDevice class for accessing battery info doesn't help me since I want to access the charge state without a iOS app on the device. I haven't been able to find this functionality in the External Device Accessory Framework either.
iTunes displays my iPhone battery level when connected, and as of iOS 8 + Yosemite, the mobile hotspot activation feature also displays the battery level of my nearby iPhone. So I know it's possible. I just want to know if it's available to any developers besides those at apple.