[time-nuts] Using GPS 1PPS for accurate period measurement

Kevin Rosenberg kevin at rosenberg.net
Fri Dec 2 17:51:23 EST 2011


On Dec 2, 2011, at 10:59 AM, Hal Murray wrote:
> I've been playing with one of the Dallas DS32KHZ parts.  I'm guessing you are 
> [...]
> Another possibility is that I didn't ground the NC pins.  (I didn't notice 
> that in the data sheet until I read it again looking for crap like that.)

Using a DS1306, I found the ground plane was essential for a stable 32768 Hz 
signal. I tried a number of ground planes in a proto board I was building. Who 
would have predicted that the best results came from the ground plane that was 
described in the 1306 datasheet. Lesson: before using a DS32KHz, I'll definitely 
connect the "NC pins" (sic) to ground as specified in the datasheet.

> You might try a pair of tvb's picPETs.

+1E3 on tvb's picPETs! Thanks, Tom!

Kevin





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