[ECOS] Re: Time problem: Clock running slow

[Grant Edwards <grant dot b dot edwards at gmail dot com>]

On 2010-09-02, Stanislav Meduna <stano@meduna.org> wrote:
> On 02.09.2010 14:52, Grant Edwards wrote:
>
>>> we just encountered a problem with our clock: It is running slow with 
>>> approximately 24 seconds per hour.
>
>> When you say "verified" do you mean with a recently calibrated
>> frequency counter?  Your error is only 100ppm (0.01%).
>
> 24 seconds per hour is way more than 100 ppm.

Doh! You're right.  I was off by a factor of 60.  It's ~6000ppm.

> What parameter controls the interrupt firing speed?
> Is there some prescaler in some counter hardware that could
> be one off (maybe with value of ~150)?

-- 
Grant Edwards               grant.b.edwards        Yow! I feel like I'm
                                  at               in a Toilet Bowl with a
                              gmail.com            thumbtack in my forehead!!


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