Le 12 nov. 2013 à 03:13, Chris Albertson a écrit :
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
hmur...@megapathdsl.net said:
A 32 KHz clock is also useful for running (well, crawling) in low power
mode.
That can be important when running off batteries.
I suspect the reason that chips don't have an option to drive the RTC from
a
1 PPS input is that there is no volume in that corner
Thanks for the input all, I think the target market for what I have in mind
is hobbyist more than time nut. I also believe the Sparkfun product I
originally pointed to is an example of a mass market offering that is 'good
enough' for almost anyone. There is a small niche of those wanting to use
From: Russ Ramirez russ.rami...@gmail.com
To: time-nuts@febo.com
Sent: Tuesday, November 12, 2013 11:22 AM
Subject: Re: [time-nuts] Maxim DS1342
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The microchip pics on the bench here actually have the oscillators in
them for the 32Khz xtal. That is, the gain and feedback to make the
crystal run are in them. All that is needed is some capacitance to
ground. This is why the SOSC (Secondary Oscillator) uses two pins. You
can also use a single
I'm thinking of doing a breakout board similar to this one
http://bit.ly/1buC4ZD for the subject Maxim chip.
Why? you may ask. Unlike many other RTC chips, this one supports a 1 PPS
drive. The specs are here http://bit.ly/1eE5vh1 on the Maxim site. There
seems to be considerable interest in
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.
Didier KO4BB
Russ Ramirez
Hi Didier,
True this could be done in SW, and I should have mentioned that I
considered that in my post. However, these chips offer several other
functions that would add complexity to the code, and I've been looking for
a reason to do a simple HW project and open source it through OSH Park
Hi
In volume a 32KHz crystal is a sub 5 cent item. In high volume very sub 5
cents. The RTC chips are *way* more expensive.
Bob
On Nov 11, 2013, at 8:06 PM, Russ Ramirez russ.rami...@gmail.com wrote:
Hi Didier,
True this could be done in SW, and I should have mentioned that I
considered
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
Because the 32Khz xtals are profoundly cheap and accurate to some extent.
Long divide by 2 chain is very simple. The xtal could be easily adjusted
close to the correct frequency. It all sort of came from watch technology.
Regards
Paul
WB8TSL
On Mon, Nov 11, 2013 at 8:06 PM, Russ Ramirez
From: Russ Ramirez russ.rami...@gmail.com
To: time-nuts@febo.com
Sent: Monday, November 11, 2013 8:06 PM
Subject: Re: [time-nuts] Maxim DS1342
Hi Didier,
...Looking across the TI and Microchip lines a bit, it strikes me as odd that
more micros supporting integrated RTCs actually use
russ.rami...@gmail.com said:
Looking across the TI and Microchip lines a bit, it strikes me as odd that
more micros supporting integrated RTCs actually use two I/Os for a 32 kHz
crystal option. Why they support an RTC is not mysterious at all, but why
not the option at to drive the 1 Hz clock
Hi Russ,
I will venture that the vast majority of applications are served with 2 pins
and a $0.10 crystal rather than the external silicon implied by a 1Hz input.
The advantage of off-chip timekeeping is the low power consumption of dedicated
RTC chips that makes them able to run from a coin
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