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Re: [ts-7000] Re: 983.04 Khz timer

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Subject: Re: [ts-7000] Re: 983.04 Khz timer
From: Bob Lees <>
Date: Tue, 18 Apr 2006 13:14:45 +0100
Hi Don

Which src are you using for the kernel ts8 or ts9?

Last July I posted a patch to -ts8 which had a new function 
static unsigned long ep93xx_gettimeoffset(void)
without this gettimeofday only returns the last tick update which is every 10 
milli-seconds.  For adjtimex (read xntpd)  to work you need a gettimeofday 
function which actually returns the number of usecs since the last tick 
update.

The patch name is linux24_ts8-lck1-cpufreq-230705.patch.gz and it is posted to 
the group file area.  It applies to -ts9 as well.

This may account for the results you and others are currently seeing.

Bob

On Tuesday 18 April 2006 02:31, Don W. Carr wrote:
> I have been running my 7260 now for about 8 hours since setting both the
> system clock with date, and the battery backed real-time clock with hwclock
> to my atomic clock that synchronizes every night. It appears that the
> battery-backed real-time clock is right on, but the system clock has lost
> about 4 seconds in 8 hours (not good). I have an application where I need
> to know with max 1 second error when a train crosses a sensor.
>
> Below you can see I ran hwclock and date at the same time, right at the top
> of the minute.
>
> $ hwclock ; date
> Mon Apr 17 20:10:00 2006  0.000000 seconds
> Mon Apr 17 20:09:56 UTC 2006
> $
>
> When I started the test, they both read exactly the same.
>
> Any ideas on how to keep the system clock in better sync? I would like
> these systems to stay within 1 second even if they are disconnected from
> the net for 24 hours.
>
> Don.
>
> On 4/17/06, Yan Seiner <> wrote:
> >  --- In  "Don W. Carr" <> wrote:
> > > Well, yes, for most applications the computers will be network
> > > attached and I can use ntp. But, that brings up the other
> >
> > question,
> >
> > > should I periodically run "hwclock --systohc" so if the computer
> > > reboots, it will come up at the right time? Or does ntp handle
> >
> > that?
> >
> > Well, I was thinking of reference clocks....  But I see from reading
> > the ntp docs that it's not what I thought....
> >
> > What is really needed is an ntp refclock driver for the TS RTC....
> > I have no idea how hard it would be to implement one... But seeing
> > as you can use NMEA messages and a pulse for refclocks it should not
> > be impossible.  Basically make it emulate a GPS signal.
> >
> > > Does anybody have the ntp client compiled for the Arm boards
> >
> > (TS-Linux)?
> >
> > Not yet....
> >
> > --Yan
> >
> >
> >
> >
> >
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>
> --
> Dr. Don W. Carr
> J. G. Montenegro 2258
> Guadalajara, Mexico
> +52-333-630-0704
> +52-333-836-4500 ext 2930

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