Re: [time-nuts] Time Code generator
And, since the requirement is to be able to do all this while portable or
mobile swings it all more in favour of a PC generated time code (less bits
and pieces to be carried around and set up)
There is a utility in the ntp package that emits IRIG based on the local
clock. Look at .../util/tg2.c
A PIC or Arduino widget would be perfect (I mess around with both). A quick
Google search for Arduino and IRIG-B didn't seem to return much of interest
but I will have another look and this time also a search on PIC as well.
You might be able to port that code to PIC/Arduino. Start by ripping out all
the options that you don't need and the command line processing and ... It
might be a lot of work but the price is right.
--
These are my opinions, not necessarily my employer's. I hate spam.
Dear time-nuts,
A PIC based IRIG timecode generator sounds very interesting! Would like to build a new stand-alone IRIG-timecode generator since my Brandywine died....
Did some Google-searches without succes.... unfortunately! :-(
Best regards, Jeroen
-----Original Message-----
From: time-nuts-bounces@febo.com on behalf of Hal Murray
Sent: Fri 12/3/2010 8:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Time Code generator
And, since the requirement is to be able to do all this while portable or
mobile swings it all more in favour of a PC generated time code (less bits
and pieces to be carried around and set up)
There is a utility in the ntp package that emits IRIG based on the local
clock. Look at .../util/tg2.c
A PIC or Arduino widget would be perfect (I mess around with both). A quick
Google search for Arduino and IRIG-B didn't seem to return much of interest
but I will have another look and this time also a search on PIC as well.
You might be able to port that code to PIC/Arduino. Start by ripping out all
the options that you don't need and the command line processing and ... It
might be a lot of work but the price is right.
--
These are my opinions, not necessarily my employer's. I hate spam.
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Jeroen Bastemeijer - EWI wrote:
Dear time-nuts,
A PIC based IRIG timecode generator sounds very interesting! Would like to build a new stand-alone IRIG-timecode generator since my Brandywine died....
Did some Google-searches without succes.... unfortunately! :-(
The generator is easy..
counting time in bcd is just arithmetic, then
you generate a bit stream, which is 100 bits long, and clock it out.
The "symbols" in the bit stream are either 0.2, 0.5, or 0.8 long (that
is, 2,5, or 8 milliseconds.
all you have to do is generate 1kHz and amplitude modulate it somehow
(I suspect that 2 resistors would do very nicely)
You could set up a 2kHz real time interrupt and toggle the output on
each RTI. count every other cycle to count the milliseconds and deal
with clocking out the symbols/bits
Depending on how you want to do it, you can generate the symbols on the
fly or just build up 1000 bits (1 per millisecond) and clock them out.
Depends on how much RAM you've got, really.
On Fri, Dec 3, 2010 at 12:54 PM, jimlux jimlux@earthlink.net wrote:
Jeroen Bastemeijer - EWI wrote:
A PIC based IRIG timecode generator sounds very interesting! Would like to
build a new stand-alone IRIG-timecode generator since my Brandywine died....
I just read the source code for the irig generator that is included with NTP.
The code is not really all that complex but there are a number a cases to
handles, for "leap warnings" and such. The code handles not only irig but
also wwv/h simulation so yu could cut out half of the lines for irig only
Of course you can't use this C code on a PIC but the algoritm is there for
you to copy. And if yu are reading this list there is agood chance it's
alrady on your computer
But to build a PIC based IRIG generator you need a way to get the
absolute time of day into the PIC, the periodic interrupt can drive it
after that point and y'd get that from deviding down a frequency
reference
=====
Chris Albertson
Redondo Beach, California
Chris Albertson wrote:
On Fri, Dec 3, 2010 at 12:54 PM, jimlux jimlux@earthlink.net wrote:
Jeroen Bastemeijer - EWI wrote:
A PIC based IRIG timecode generator sounds very interesting! Would like to
build a new stand-alone IRIG-timecode generator since my Brandywine died....
I just read the source code for the irig generator that is included with NTP.
The code is not really all that complex but there are a number a cases to
handles, for "leap warnings" and such. The code handles not only irig but
also wwv/h simulation so yu could cut out half of the lines for irig only
Of course you can't use this C code on a PIC but the algoritm is there for
you to copy. And if yu are reading this list there is agood chance it's
alrady on your computer
But to build a PIC based IRIG generator you need a way to get the
absolute time of day into the PIC, the periodic interrupt can drive it
after that point and y'd get that from deviding down a frequency
reference
I can think of a couple ways to do it..
One, if you have a IRIG reader, is to just have buttons to push to step
up and down, and left and right.
I think I'd go with some sort of serial port interface, though. Maybe
you could do something takes a NMEA sentence?