I tried to follow the following thread to make a cable that will start the phone into car mode:
I have a working OTG cable and a USB A-A. When I connect the cable to a charger and plug it into the phone I just get a notification that says "The USB host cable is plugged in. Unable to charge the device"
So I did a little more looking and people said to trigger car mode pins 4 and 5 must be connected. I hacked up a cable and jumped them together. Plugging in the hacked up cable gives the same notification - "The USB host cable is plugged in. Unable to charge the device"
So apparently my OTG cable is working as intended but doesn't launch car mode.
Does anyone know what the M7 uses to detect the car dock? I don't want the stock HTC car dock since it goes on the windshield and I want it clipped into a vent.
Edit: Looks like this may be in the source somewhere...
Anyone familiar with the kernel source able to help? I'm going to do my own searching but I'm hardly familiar with linux.
Edit 2: Found values for HTC One X. Just don't have resistors handy:
10kOhm triggers auto dock mode
68kOhm triggers desk dock mode (also, a 47kOhm triggers desk dock mode)