[time-nuts] Maxim DS1342

[Chris Albertson]

> You want to drive the RTC with an external PPS to get time/date into an
> >> Arduino?
> >> Why not feed the PPS to the Arduino and have it compute date and time?
> >>
> >> It is really not that hard to count seconds. You don't really need an
> >> external chip to do that.


Typically you need more fine time resolution them just a seconds counter.
 Especially if you are using an Arduino, you are maybe building a robot or
real-time controller and want to measure something like "Milliseconds per
revolution"  so you need a faster running counter and then you want to
calibrate that counter

A typical method is to have the PPS trap the faster counter, than you can
see how many periods per second your counter is moving.  You can mount for
a 1,000 seconds and get a pretty good idea.  Then you use the fast counter,
now that you know it's rate for you timing.

So you don't need an external chip if you are willing to track the rate of
the free running clock.

-- 

Chris Albertson
Redondo Beach, California