[time-nuts] GPSDO Alternatives

Bob Camp lists at rtty.us
Thu Dec 6 23:25:33 UTC 2012


Hi

That would be an input capture rather than an interrupt.

Bob

On Dec 6, 2012, at 6:16 PM, Hal Murray <hmurray at megapathdsl.net> wrote:

> 
> albertson.chris at gmail.com said:
>> You'd have to seriously divide down the output from the 10MHz OCXO if you
>> were going to use it as an interrupt.  Maybe to divide by 10,000? and even
>> at the higher clock rate you'd still have poor resolution.
> 
>> I image each interrupt handler would sample some internal counter and the
>> background task would look at the delta between the two and adjust the DAC
>> to drive the OCXO to close the difference.   The resolution would be
>> (maybe?) a "handful" of clock cycles.   Given enough time, say a 1000 second
>> period it might wrk well enough.  I can't know without doing a more detailed
>> design 
> 
> Do some of the counter/timer modules have an option to run the counter off an 
> internal clock and copy the value into another register on an external signal?
> 
> That avoids any interrupt latency.
> 
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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