User avatar
Richard-TX
Posts: 1549
Joined: Tue May 28, 2013 3:24 pm
Location: North Texas

RTC Clock - Why?

Sun Dec 29, 2013 6:29 pm

Why add a RTC clock? The long term accuracy of ntp is far better than any RTC.
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip

User avatar
DougieLawson
Posts: 39838
Joined: Sun Jun 16, 2013 11:19 pm
Location: A small cave in deepest darkest Basingstoke, UK
Contact: Website Twitter

Re: RTC Clock - Why?

Sun Dec 29, 2013 6:37 pm

What if you want good timing but don't have a good connection to the Internets?

A DS1307 breakout board (like the one my twin brother got me for Xmas) costs less than a tenner.
Note: Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

Criticising any questions is banned on this forum.

Any DMs sent on Twitter will be answered next month.
All fake doctors are on my foes list.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 27062
Joined: Sat Jul 30, 2011 7:41 pm

Re: RTC Clock - Why?

Sun Dec 29, 2013 6:43 pm

Never mind a good connection - in remote locations there may not be any connection (and remote could be the bottom of the garden...)
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed.
I've been saying "Mucho" to my Spanish friend a lot more lately. It means a lot to him.

User avatar
Richard-TX
Posts: 1549
Joined: Tue May 28, 2013 3:24 pm
Location: North Texas

Re: RTC Clock - Why?

Sun Dec 29, 2013 6:52 pm

DougieLawson wrote:What if you want good timing but don't have a good connection to the Internets?

A DS1307 breakout board (like the one my twin brother got me for Xmas) costs less than a tenner.
I guess I am absolutely dependent on a fast connection to the internet. Even without that, I would have one machine in the house be a ntp server and have the Rpi's adjust to that using ntp over wifi.
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip

User avatar
DougieLawson
Posts: 39838
Joined: Sun Jun 16, 2013 11:19 pm
Location: A small cave in deepest darkest Basingstoke, UK
Contact: Website Twitter

Re: RTC Clock - Why?

Sun Dec 29, 2013 10:34 pm

Oh yes, I have an Ubuntu server that runs ntpd.
Currently synced to five stratum 2 servers.
I even ran it with my Garmin ETrex hooked up to get a stratum 0 time ref for an experiment.
Note: Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

Criticising any questions is banned on this forum.

Any DMs sent on Twitter will be answered next month.
All fake doctors are on my foes list.

User avatar
Richard-TX
Posts: 1549
Joined: Tue May 28, 2013 3:24 pm
Location: North Texas

Re: RTC Clock - Why?

Sun Dec 29, 2013 10:43 pm

DougieLawson wrote:Oh yes, I have an Ubuntu server that runs ntpd.
Currently synced to five stratum 2 servers.
I even ran it with my Garmin ETrex hooked up to get a stratum 0 time ref for an experiment.
That is pretty hard core. That is a lot more precision than I would ever need.
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip

PaulCheffus
Posts: 381
Joined: Tue May 29, 2012 2:51 pm
Location: Lincolnshire UK

Re: RTC Clock - Why?

Fri Jan 03, 2014 5:41 pm

Richard-TX wrote:Why add a RTC clock? The long term accuracy of ntp is far better than any RTC.
Hi

In my case it isn't for accuracy.

I have my Pi connected to a Weather Station and when the Pi boots it starts the Weather software. I have found when we have a power cut the Pi will boot far quicker than the router and then the weather software wont start due to the time being wrong.

Cheers

Paul
Procrastination - The Thief of Time.

Return to “Interfacing (DSI, CSI, I2C, etc.)”