Garmin GPS - Communications error (USB) while loading maps into GPSMAP 76C

Author

Communications error (USB) while loading maps into GPSMAP 76C

Hans-Georg Michna

2006-09-20, 10:33 am

Does anybody have any experience or good ideas when it comes to
communications errors on a USB connection? I haven't had this
before and am not sure what suddenly causes it. The only thing I
can remember is that I swapped a few USB devices from one port
to another.

The error is persistent. I was unable to load 115 MB of maps
into the Garmin GPSMAP 76C, because at some time during the load
I received the communications error, typically around 50%
loaded, during several attempts.

I then went to another computer and loaded the map set without a
hitch. But that's no solution.

It seems that two defects cross each other here. One is that the
USB communication occasionally fails, and the other is that the
Garmin device and the software is unable to recover from that
and continue. I don't know whether USB data flows are meant to
be free of delays or errors.

Is this a widespread problem or do I have a rare affliction
here?

Hans-Georg

--
No mail, please.

Jack Erbes

2006-09-20, 3:33 pm

Hans-Georg Michna wrote:

> Does anybody have any experience or good ideas when it comes to
> communications errors on a USB connection?
<snip>

System timeouts? Like going into standby or something?

Jack

--
Jack Erbes in Ellsworth, Maine, USA (jackerbes at adelphia dot net)
(also receiving email at jacker at midmaine dot com)

Hans-Georg Michna

2006-09-21, 10:33 am

On Wed, 20 Sep 2006 13:43:05 -0400, Jack Erbes wrote:

>Hans-Georg Michna wrote:

><snip>

>System timeouts? Like going into standby or something?

Jack,

thanks for replying! No, nothing of the sort.

But I have identified one culprit. A USB TV adapter seems to be
a factor. When I pull it, the problem disappears.

So I have a workaround. Stop watching (or recording) TV while
uploading maps to the Garmin device, and Garmin may be absolved.

However, this does not necessarily mean that the TV adapter
actually causes the problem. I would expect that one USB device
is sufficiently shielded from another that, if one does
something, the other should not malfunction.

Perhaps the USB controller is flakey, either individually or by
design. The other alternative is that the Garmin GPS is flakey.
The TV adapter works fine, after all.

I don't understand enough of USB to make any judgment, but I
wouldn't be surprised if it is unreliable by design.

Any further ideas and hints are always welcome.

Hans-Georg

--
No mail, please.

trgraham@shaw.ca

2006-10-18, 12:33 pm

Hans-Georg Michna wrote:
> Does anybody have any experience or good ideas when it comes to
> communications errors on a USB connection? I haven't had this
> before and am not sure what suddenly causes it. The only thing I
> can remember is that I swapped a few USB devices from one port
> to another.
>
> The error is persistent. I was unable to load 115 MB of maps
> into the Garmin GPSMAP 76C, because at some time during the load
> I received the communications error, typically around 50%
> loaded, during several attempts.
>
> I then went to another computer and loaded the map set without a
> hitch. But that's no solution.
>
> It seems that two defects cross each other here. One is that the
> USB communication occasionally fails, and the other is that the
> Garmin device and the software is unable to recover from that
> and continue. I don't know whether USB data flows are meant to
> be free of delays or errors.
>
> Is this a widespread problem or do I have a rare affliction
> here?
>
> Hans-Georg
>
I had the same problem. Turned out I was working USB through a hub. When
I went direct to the USB port on the computer, everything worked fine.

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