[LinuxPPS] assert/clear

[Remco dB]

On Monday 19 July 2010 21:07:19 Paul wrote:
> I was recently asking for advice about using an oncore, progress is
> being made, thanks to Reg and Remco.
> But I see another more basic problem. I see asserts incrementing, but
> not my clears (i.e. it stays the same). How can an asserts be seen
> without a clear between each one?

Hi Paul,

Before LinuxPPS was 'fully included' in the kernel, I observed equal amounts 
of clears and asserts. As of 2.6.34 I also have your observation.

AFAIK LinuxPPS / ntpd / Oncore driver want to have the 'active edge' only. 
So when this is the falling edge (CLEAR) then this has to be inserted in 
/etc/ntp.oncore.0

E.g. here cat /sys/class/pps/pps0/{clear,assert} (clear being the 
'active edge' due to the inverter in my interface) yields: 

1280318924.000001384#3929837
1276389352.168599915#265

This system is running good and is within +/- 2us 'on time' with an offset 
within the 5 - 35 ns range averagely.

Remco