[ntp:questions] Re: linux parallel port pps hack

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Tue Aug 26 11:20:05 UTC 2003


ptrojane at mion.elka.pw.edu.pl (Piotr Trojanek) writes:

> In article <vhmtl43m3mp184 at corp.supernews.com>, Mr Happy wrote:
> >I've hacked up David Schwartz' linux shm driver to work on
> >the pc parallel port. Its running on thrall.wraith.sf.ca.us
> 
> why don't extend PPSapi from PPSkit to work with parallel port?

Just send some code that modifies the parallel port driver to call
some routine if an interesting event happens. I would try to do the
rest...

Regards,
Ulrich

> 
> how much from precision of PPS you lose when timestamping it in user
> level, which includes contex switching?
> 
> maybe if PPS irq on parallel port could be timestamped in interrupt
> service routine and then provide this data to user space with some
> ioctl?
> 
> why don't use PPS state and averaging code from kernel implementation?
> 
> -- 
> Piotr Trojanek



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