Re: [gpsd-users] Ublox EVK-M8T

[Gary E. Miller]

Yo Denny!

On Tue, 19 Sep 2017 16:12:19 -0700
Denny Page <address@hidden> wrote:

> > We have other people reporting success.  
> 
> I’ve seen reports of success with the M8, but not with the M8T
> (timing chip). I have seen reports of failure by others previously in
> this list which is why I asked the question a couple of weeks back.

Well, all that matters is that we get you running as a good eample of M8T.

> > Are you sure you do not have a voltage level problem instead?  Many
> > ublox output at 3.5V and most serial inputs can not handle that.  
> 
> Yes, I’m quite sure. The EVK is pretty well documented. It offers
> 3.3V on a standard test connector and +/- 12V RS-232 on a DB9.

Documentation is one thing.  But, have you put a voltmeter or scope on it?

> Further, I have also tested pin 7 (RTS) on the EVK's DB9 to pin 1
> (DCD) on the host. It works the same as if pin 1 on the EVK’s DB9 is
> used. The problem occurs is if you connect either PPS signal to pin 7
> (RTS) on the host. 

What does "stty < /dev/ttyXX" say at that time?  Anything interesting in
the kernel config or kernel logs?

> With the cable described above, things work as expected. Both ppstest
> and gpsmon (sans gpsd) indicate good PPS.

Yes, you already said that.

> > A pulse has two edges.  PPS uses the eading one, and ignores the
> > trailing edge.  
> 
> Okay, my bad. I misinterpreted what the “reject” meant.

Very common misunderstanding.  I'm just changed 'reject' to 'ignore' in
git head, but Im not sure that is really better.  Any recomendation for
how we could improve the message?

> So, any speculation you can offer as to what the problem is?

Uh, which problem?  I thought you just said the PPS is fine?

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin

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