[time-nuts] Frequency Dividers

SAIDJACK at aol.com SAIDJACK at aol.com
Tue Aug 8 16:45:22 EDT 2006


Hi Randy,
 
I guess they like the intellectual challenge of tweaking PIC bits :)
 
There is what I think may be a better way to generate the 1PPS: you  can use 
an Arm micro such as the Philips LPC2102 series to generate a 1PPS  output 
with 16.7ns settability:
 
these micros have counter/timers with 32 bits of resolution, they can run  at 
60MHz (6x the input of 10MHz using an internal PLL), and can generate a pulse 
 output ("counter Match") anywhere in the second with 16.7ns resolution. They 
can  even generate multiple outputs, say 1PPS, 10PPS, 100PPS etc all in  
paralell.
 
On top of that, they can generate a software-selectable pulse-width, and  can 
synchronize themselves to a GPS 1PPS input.
 
Best of all, they are <<$2 in volume.
 
For cheap eval boards, see:
 
_http://www.sparkfun.com/commerce/product_info.php?products_id=667_ 
(http://www.sparkfun.com/commerce/product_info.php?products_id=667) 
 
That board can generate 5 independent pulse-outputs for $30.
 
bye,
Said


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