HomeHardware


How to get iTrek M7 GPS default to 5Hz instead of 1Hz for USB?
Nrgizerbunny
Hi all,

I've had my iTrek M7 for a while now, and it has been running on Bluetooth mode and interfacing with Garmin Mobile PC at 5Hz.

What I would like to do is have it connected to my USB socket, and have the data go down the USB line to the PC. I have tried GPSGate, but the problem is when I use that, it seems to default to 1hz, and the update is really jerky.

Oon 5hz Bluetooth its super smooth. Anyone got any ideas? The iTrek uses a silicon labs USB to serial interface.

Thanks

NRG
tcassidy
I don't think it is defaulting to 1Hz - more likely to 4800 bps. As it is not possible to send 5 Hz data at 4800 (it won't fit), you get a jerky display. The problem is Mobile PC can't handle 115,200 bps, the USB data rate of the iTrek. I think it tops out at 38,400 bps or thereabouts.

Make sure the input for GPS Gate is set to 115,200 on the appropriate COM port and see what the output looks like.

Terry
tcassidy
I just tried it changing the iTrek to 5 Hz and setting up the COM port in GPS Gate to 115,200 (COM 10 in my case). The hardest part was getting Mobile PC to switch from BT to serial as I have another BT GPS on all the time. I switched it to COM 6 (one of the GPS Gate outputs) but when I enabled it, Mobile PC continued to search BT. A restart of Mobile PC and it found the output right away and ran smoothly.

Switching between BT and serial has been a problem with Mobile PC for some time. It appears to be resolved in 5.00.70 but that version apparently has other issues. A second restart of Mobile PC will usually resolve it with other versions.

Terry
Nrgizerbunny
Mmm, that didn't work for me. I wonder why.
tcassidy
What part of it didn't work?

Terry
Nrgizerbunny
I set the device manager ports "silicon labs" to 115200, set the port up on GpsGate, and then went to Garmin Mobile PC. In there it appears to be updating only once a second. Pretty sure the iTrek is at 5hz, just something to do with Garmin Mobile PC. I exited, restarted a couple of times, it's still not working right! Will try some more.
tcassidy
Changing the Device Manager settings for COM ports does nothing - just leave it at default.

In GMPC, click on the satellite in the top right corner, click the disable button in the resulting screen and choose the Use Serial GPS radio button. Choose one of the GPS Gate COM ports from the list and click Enable. If GMPC still says Scanning Bluetooth, restart it. It should come up showing the satellite bars and if you check that page again, it will list the COM port you set.

Maybe the easiest trick is to disable BT on your laptop if you are not using it for something else.

Terry
tcassidy
If you are not sure that GMPC is actually seeing 5Hz updates, start GPS View and point its input to an output port of GPS Gate. Select 38,400 bps (probably what GMPC will ask for from GPS Gate) and try the check button for refresh rate. It should stay at 5 Hz.

Terry
Nrgizerbunny
I'll try that! It's on my car PC, so I'll see how it goes.

Thanks very much.
Nrgizerbunny
Just a bit of an update for people.

I managed to get it to work, I had to go into GPSView and turn all the things with letters on them to 0, from memory they were things like GAA, GSA? Then I switched them on one at a time. One or two or more of those things cause Garmin to update slowly. Not sure which item it is.
tcassidy
I certainly have no idea what you are talking about. Mobile PC works fine with the iTrek at default settings when used with GPS Gate.

Terry
Nrgizerbunny
Terry, the iTrek comes with a setting program called GPSView,

Some of the settings in there control certain functions like dynamic GPS, GAA, GSA and a whole load of other ones. There is a setting in there (I'm not sure which one) that causes Garmin Mobile PC to update at only 1Hz. I am not talking about the 1hz-5hz drop down box.

Hope that helps
Nrgizerbunny
Here's a photograph of what I'm talking about, disregard the red circle, that controls the speed, its the drop down boxes above that have 1's and 0's that screw Garmin Mobile PC up.

tcassidy
Looks the same as mine but I didn't change anything.

Terry
laptopgpsworld.com About