Hi,
I make a USB DAC that enumerates and plays on all platforms except on a new iPhone 13. Well, it plays on the '13 as well, but only when power is injected by a USB hub.
The DAC is device powered. The VBUS line only powers a small DC load for detection, some 3mA. It also has some filtering capacitance that may contribute inrush capacitance. Before I start hacking with a soldering iron it would be good to know if this is a known problem.
Playing from iPhone 7s / iOS 15 over an Apple Camera Adapter worked perfectly both through a powered USB hub and directly on its own. But playing from iPhone 13 / iOS 16 only works with the powered hub. The iPhone 13 doesn't find the DAC when it has to deliver even a tiny amount of power to it. I get no error messages.
I have changed the USB descriptors to say that it is Device Powered and will draw 0mA. The iPhone 13 behaves the same way before and after this change in the code.
Do you know if there is a spec for power delivery and inrush current from the Lightning plug of the iPhone 13 and how it might differ from that of the iPhone 7s?
Thanks,
Børge
I make a USB DAC that enumerates and plays on all platforms except on a new iPhone 13. Well, it plays on the '13 as well, but only when power is injected by a USB hub.
The DAC is device powered. The VBUS line only powers a small DC load for detection, some 3mA. It also has some filtering capacitance that may contribute inrush capacitance. Before I start hacking with a soldering iron it would be good to know if this is a known problem.
Playing from iPhone 7s / iOS 15 over an Apple Camera Adapter worked perfectly both through a powered USB hub and directly on its own. But playing from iPhone 13 / iOS 16 only works with the powered hub. The iPhone 13 doesn't find the DAC when it has to deliver even a tiny amount of power to it. I get no error messages.
I have changed the USB descriptors to say that it is Device Powered and will draw 0mA. The iPhone 13 behaves the same way before and after this change in the code.
Do you know if there is a spec for power delivery and inrush current from the Lightning plug of the iPhone 13 and how it might differ from that of the iPhone 7s?
Thanks,
Børge