Re: [gpsd-dev] SemPiTernal - Bounding PPS uncertainty

[Hal Murray]

>> Both are triggering on the rising edge.

> I want to be very sure I know what you're asserting here.  Are you saying
> that you *know* the pps-gpio driver reports the leading edge in both cases?
> While this is certainly plausible I'd like to know your authority for it.
> It's a crucial, delicate point on which I would hate for us to inadvertently
> spread misinformation. 

I was claiming that both devices are doing the right thing with the current 
broken kernel that doesn't support the falling/clear edge.

I just verified with a scope that the PPS pulse from an Adafruit HAT is 100 
ms wide and starts with a rising edge.

I have an old Uputronics, but it's tie wrapped up on a shelf where I can't 
easily get a scope probe on it.  They use uBlox.  I'm not sure which one.  It 
is unlikely to make any difference.


> The default pulse width should be in the data sheets.

I couldn't find it.  Grumph.  So change that to "will be in good data sheets."




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