[time-nuts] Re: Ryzen mobos with serial port for Garmin GPS?

[Andy Talbot]

Well, yes.   No one would rely on a windows PC for timing accuracy, surely
This is what I did to get a fully coherent timing and frequency locked
system for a narrowband LF receiver using an FTDI interface to a PC.
http://g4jnt.com/Coherent_LF_Receiver.pdf

Andy
www.g4jnt.com



On Fri, 5 Nov 2021 at 18:44, Bill Dailey <docdailey at gmail.com> wrote:

> There is significant jitter using USB for timing.  Has been done poorly
> for a long time.  Well known.
>
> Bill Dailey
>
> Negativity always wins the short game. But positivity wins the long game.
> - Gary Vaynerchuk
>
> Don’t be easy to understand,
> Be impossible to misunderstand
> - Steve Sims
>
> > On Nov 5, 2021, at 1:33 PM, Andy Talbot <andy.g4jnt at gmail.com> wrote:
> >
> > Use FTDI USB serial ports - you can't go wrong with them.
> > https://ftdichip.com/
> >
> > I have, at the last count, used something like 200 of their FT232 device
> in
> > one form or another on the shack PC.   I know that, because device
> manager
> > has registered up to COM200.  Every time a new one is plugged in, a new
> COM
> > port is set up.
> >
> > Andy
> > www.g4jnt.com
> >
> >
> >
> >> On Fri, 5 Nov 2021 at 18:26, Alec Teal <alec at unifiedmathematics.com>
> wrote:
> >>
> >> A friend of mine who lives and breaths this stuff (I wont tell you what
> >> he does - but suffice to say he's authoritative) basically said to me on
> >> something about serial ports that you can't go wrong with USB stuff,
> >> even on Linux.
> >>
> >> Would that work?
> >>
> >> Serial ports certainly are getting scarce! You'd get 2 to a board an
> >> embarrassingly long time ago!
> >>
> >>> On 05/11/2021 06:10, Darren Freeman wrote:
> >>> On Thu, 2021-11-04 at 22:36 -0700, Rich Wales wrote:
> >>>> However, mobos with a serial port are becoming harder to find.
> >>> That's not really been my experience, they just moved it to a header.
> >>> You will need to supply a DE9 to ribbon cable, say on a bracket, or
> >>> installed in a cutout elsewhere in the case.
> >>>
> >>> This is the first one that I checked, and it has such a port labelled
> >>> COMA, along the left/bottom edge.
> >>> https://www.gigabyte.com/Motherboard/B450-AORUS-M-rev-1x/sp#sp
> >>>
> >>> Also note that the Linux PPS driver supports the standard PC parallel
> >>> port, which you can usually find as a header. If you are having
> >>> performance issues with one, try the other. (But you may need to supply
> >>> negative-going edges to the parallel port.)
> >>>
> >>>
> >>> Have fun,
> >>> Darren
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