[arm-allstar] Adding a Real Time Clock to the BBB

[Doug Crompton]

The GPS approach might be a fun project but I think it is a little overkill for a clock. The other issue would be that it requires a RF signal so in most cases you would need an outside antenna for it to work.

How is the time derived from the GPS? Reading the pps or the serial stream. If it is the serial stream then using a usb to serial adapter would work fine. 

The late kernels that we are using, which greatly improve the operation of Allstar, also have the downside that the cape manager is not ported yet. Using a USB to serial adapter is a viable option. Also the i2c and spi interfaces do work.

There are a ton of adapters out there. Here is one that works.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812119246
73 Doug
WA3DSP
http://www.crompton.com/hamradio


Date: Mon, 24 Nov 2014 18:51:47 -0600
From: w0kgw3 at gmail.com
To: arm-allstar at hamvoip.org
Subject: Re: [arm-allstar] Adding a Real Time Clock to the BBB

I wrote up how to connect the adafruit to the BBB 1.1 image, but with the update to 1.2 I'm stuck on device overlays no longer working correctly. Haven't had word back on the conundrum yet.


Cheers,
Joel
W0KGW


On Mon, Nov 24, 2014 at 6:43 PM, Mark Herson, N2MH <n2mh at n2mh.net> wrote:
Doug,



While you are at it, do you think you could include an ntp server running

from a gps? I believe ADA Fruit has an inexpensive gps or one could use

something like a Garmin 18. This approach might be desirable for some

people and would also get around the accuracy issues with the real time

clock module. Accurate top of second would come from the 1 PPS line and

time/date would come from an NMEA sentence.



73, Mark, N2MH



> Date: Mon, 24 Nov 2014 09:36:34 -0500

> From: Doug Crompton <doug at crompton.com>

> To: "arm-allstar at hamvoip.org" <arm-allstar at hamvoip.org>

> Subject: [arm-allstar] Adding a Real Time Clock to the BBB

> Message-ID: <BLU172-W14D2B7513047E0D3B3238BA720 at phx.gbl>

> Content-Type: text/plain; charset="iso-8859-1"

>

> I know at least one person has had a problem with accurate time on the

> BBB running Allstar. He was not able to reach an ntp server. In most all

> cases this will NOT be a problem but if for some reason you want to run

> the BBB offline or you do not have ntp access due to blocking or for any

> reason you could easily add a Real Time Clock to the BBB to achieve

> accurate time.

>

> I built a clock and wrote a how-to detailing how to implement it in

> Archlinux on the BBB. The cost is minimal coming in at under $10 for the

> clock kit. This clock works fine and it appears to be accurate at least

> at room temperature. I did no testing at temperature extremes. The method

> of doing this is still somewhat experimental and there probably will be

> changes as we go along on exactly how the clock is implemented in the

> code but for now this is a viable option for those who have a need to add

> it. Software support for this will be added to the next image release.

> Again I want to emphasize that having this clock is NOT a requirement for

> most all situations under which the BBB is used but you can certainly

> choose to experiment and try it out if you like.

>

> The link to the how-to was added to the hamvoip.org web page. Here is a

> direct link -

>

> http://www.crompton.com/hamradio/BBB_realtime_clock/

>

>

> 73 Doug

> WA3DSP







_______________________________________________



arm-allstar mailing list

arm-allstar at hamvoip.org

http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar



Visit the BBB web page - http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/




_______________________________________________

arm-allstar mailing list
arm-allstar at hamvoip.org
http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar

Visit the BBB web page - http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/ 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.hamvoip.org/pipermail/arm-allstar/attachments/20141125/05e5aa8b/attachment-0001.html>