[time-nuts] WWV / WWVH / WWVB

Chris Kuethe chris.kuethe at gmail.com
Wed Jan 7 11:55:48 EST 2009


On Wed, Jan 7, 2009 at 6:52 AM, David M. Witten II <wittend at wwrinc.com> wrote:
> James R. Gorr wrote:
>> Have you been able to RX WWVB with it (even if you haven't written anything to decode it)?
>
> No, I haven't had time to make one work.  It seems like a nice little
> package, but how useful and for what purposes I am not yet certain.  My
> curiosity just got the better of me (again).  The device produces a
> pulse train that encodes the WWV information.

It's super-easy to get bits out.

(component side up, solder pads on the bottom edge)
[1][2][3][4][5][6][7][8]

1) GND
2) VCC
5) GND
6) OUT
7) ~OUT

pin 5 is the enable/power-on pin. ground it to turn the module on.
then you get bits on pin 6 and 7.

>> I wonder what the no CPU means?
>
> That worried me too.  I read the manufacturer's information and it seems
> that this is sometimes used with an Epson 4 bit CPU.  But any CPU/MCU
> should be able to do the job.  A small PIC or AVR should be able to
> handle it easily.

I have one of these modules connected to an arduino (AVR)... for the
moment i hacked up an ugly little logger that just samples at 100Hz,
toggles the LED and prints the samples. I need to spend some quality
time with the manual and read about input capture.

> There is an article in the November '08 Circuit Cellar Magazine that
> uses this module with a Freescale DEMO9S08QG8:

http://www.projects-lab.com/?p=719
ftp://ftp.circuitcellar.com/pub/Circuit_Cellar/2008/220/Nickels-220.zip

> The article gives some details of decoding, but I don't have Freescale
> tools and have a satisfactory (better) NTP server, so I won't duplicate it.

searching for "AVR WWVB" and "AVR DCF77" turned up some leads.

http://www.ringolake.com/pic_proj/WWVB/wwvb.html
http://www.mulder.franken.de/ntpdcfledclock/
http://www.embedds.com/neat-binary-dcf-77-clock/
...

-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?




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