[time-nuts] Very slow freq. counter / event counter

Chris Albertson albertson.chris at gmail.com
Fri Apr 18 23:50:55 UTC 2014

Windows is likely not the best OS for this use.  Other OSes are good to
about 2 microseconds.
The code you posted, I just read it.  It's doing "user land" rimming.  OK I
guess if nay about .01 second level accuracy is required but you can't even
be sure of that if other stuff is running.   The interrupt based PPS logger
on Linux, BSD and others really does a decent job at the "few uSecond"
level because the time critical part is just a very few instructions inside
an interrupt handler.  Then the logging and disk I/O is in non-real time.
 It's free and runs on even very old hardware from the 1990's

On Fri, Apr 18, 2014 at 3:32 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

> > PCs can do that without the chip.  Connect the pulse to the DCD
> > line of an RS232 port and it will get logged with a uSec timestamp.
> > It works for any frequency from maybe 1kHz to 0Hz.
> Yes, this works because the OP only needed 1/100th second resolution.
> For (windows) PC-based frequency or event counting or timestamping see:
> PC Time Stamping Counter using serial port
> http://leapsecond.com/tools/pctsc.c
> http://leapsecond.com/tools/pctsc.exe
> PC Frequency Counter using serial port
> http://leapsecond.com/tools/pcfc.c
> http://leapsecond.com/tools/pcfc.exe
> /tvb
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Chris Albertson
Redondo Beach, California

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