|Subject:||Re: [Paparazzi-devel] Tiltrotor-Project|
|Date:||Fri, 6 May 2016 13:06:30 -0300|
Yes, I had the same problem before. Please see the answers from Piotr (I think he’s OK for me to publish his answer here…) and description of my problem below.
I never changed the diode as if was OK for me to connect GND to ADC2 for my precise application (not on a UAV).
It seems that I have 5V on the USB_VBUS line… so Vin ! (I measured this USB_VBUS line not directly on the USB port but on the free « connection holes» under the board where it is written USB, I imagine it is the same, I measured between the first and last hole).
Please note that this problem appeared after few tests, but was not present at the beginning (the board was working perfectly).
Adding a jumper between GND and ADC2 solves the problem, thanks a lot, it is more convenient for me to present the board.
But have you any idea about what could have happened ?
I think my Lisa board is dying step by step, at least around the USB alimentation…
Until now, when I plugged the USB cable, everything was OK. Now, nothing happens : the USB does not power on the board anymore.
So I have to power on the board (not from USB), in this case it is in luftboot mode (always, if I do not connect the GND and ADC2), and then I can upload the firmware from the USB !
Have you an idea about what happens to the board ? Some components failures ?
This sounds like the zener diode D3 connecting the power from the USB to the main power system is doing things that it should not. You could try to temporarily bypass that component and see if that works. It is normally there to protect the USB connector in case you power the Lisa/M from more than 5V power sourcew at the same time while USB is plugged in. Also it prevents the CPU to think that the USB is plugged in, while you are powering it from external power source, and USB is not plugged in. Both symptoms you describe, going in boot loader while applying external power and not getting power to the system from USB, point to that component. You should be able to easily replace that part by swapping it with another .7 dropout zener diode in an 0603 package.
I have attached a picture highlighting the part in question with a red circle.
I hope this helps.
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