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Fix for UAEFI sometimes not starting without USB connecteed
Posted: Thu Apr 11, 2024 10:30 pm
by gurov
- image.png (2.71 MiB) Viewed 1783 times
from discussion on discord:
5vp does not light up with just 12v below a certain battery voltage, causing a no-start condition
this was traced down to a severe enough drop at the main 5v regulator that would cause the main MCU to power down, aborting enabling 5vp, entering a loop.
fix is rather crude, but it's to force 5vp to initialize forcefully, MCU or not.
10k resistor between pin 7 and 5v rail, like in the picture.
Re: Fix for UAEFI sometimes not starting without USB connecteed
Posted: Fri Apr 12, 2024 12:29 am
by AndreyB
gurov wrote: ↑Thu Apr 11, 2024 10:30 pm
this was traced down to a severe enough drop at the main 5v regulator that would cause the main MCU to power down, aborting enabling 5vp, entering a loop.
We still do not know real root cause right?
Similar looking boards one would work another would not, right?
https://github.com/rusefi/uaefi/issues/59
Re: Fix for UAEFI sometimes not starting without USB connecteed
Posted: Fri Apr 12, 2024 12:31 am
by gurov
correct, still don't know the actual root cause, just breadcrumbs of symptoms with comparison to good board