I am trying to use Khadas in the car to simulate a mobile phone device (I posted about it one year ago).
The application I am using to mirror khadas in the car is called carbitlink, it using mirroring through usb.
(I did some mirroring using other methods and it worked but the original car application does not), I need to make this work because I want to use the original car applications where people can’t do programming in their cars.
After doing a lot of research, I have a strong feeling the problem related to usb OTG technology.
I tried many other sbc’s like raspberry pi, odroid N2, … etc and only the odroid worked.
Only sbc that has micro usb (other than type c usb) worked in that case.
I reviewed the schematic of both edge 2 and odroid n2:
ID pin is not connected (1)
(1) Since ID pin is not connected, it means Edge2 USB C is always in host mode (master mode) just like other USB’s
So it can never be a real OTG unless ID pin is grounded and added to some components of diodes and ESD protectors.
Also, the Vbus of OTG seems to be connected to a resistor of 40k ohms? why it is taken to ground by the resistor like a dummy load or I am getting it wrong maybe
Another thing the component SMD121008 ( CUWI11T-900Y) is of no use because the OTG function is not being used
We can see the difference in the number of pins that is related to the OTG usb, in the micro usb it has 5 pins (Vbus, DN, DP, GND, ID), I think the ID pin deciedes what type of OTG this is (I read if ID grounded the OTG becomes a Host OTG, if it is floating the OTG becomes a normal USB and not OTG).
In the usb C only 4 pins (2 shorted for the USB C turning upside down protocol) so it is only 2 pins associated to the OTG (probably 4 because one to Vbus and other to GND).
I am thinking of making an adapter to solve the problem and using only few components from the processor otg ID to external small board and since for DP and DN edge2 is taking care of.
But I don’t know where is the OTG ID pin in the processor and if it is connected anywhere on Edge2.
Also the GND and VBus for the OTG (I see that USB C in khadas is shorting all Vbuses and GND, can I use any of the to power the micro usb adapter I am planning to create? (the volt is 3.3 right?)
Thank you and hope I get a reply from your side great Khadas engineers …
(Sorry if I missed something out of ignorance since I am a mechanical engineer not embedded systems but electronics has been a hobby to me since lonngg time )