Fedora7 USB GPS problem

Paul Olson paulo at olson-consulting.com
Mon Nov 19 06:15:03 UTC 2007


Mikkel L. Ellertson wrote:
> Paul Olson wrote:
>   
>> Hello-
>>    Having a problem getting a DeLORME USB GPS LT-20 device working with
>> my Fedora 7 laptop.  It is supposed to work with the cypress_m8 serial
>> module.
>>
>> when I loaded the module and plugged in the device, it created the
>> device (a ls -l in /dev shows this:  crw-rw---- 1 root uucp 188,  0
>> 2007-11-18 22:24 /dev/ttyUSB0).  it shows up when I do a 'cat
>> /proc/bus/usb/devices':
>> T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  5 Spd=12  MxCh= 0
>> D:  Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
>> P:  Vendor=1163 ProdID=0200 Rev= 0.01
>> S:  Manufacturer=DeLorme Publishing
>> S:  Product=DeLorme USB Earthmate     C:* #Ifs= 1 Cfg#= 1 Atr=80
>> MxPwr=100mA
>> I:* If#= 0 Alt= 0 #EPs= 2 Cls=03(HID  ) Sub=00 Prot=00 Driver=cypress
>> E:  Ad=81(I) Atr=03(Int.) MxPS=  32 Ivl=6ms
>> E:  Ad=02(O) Atr=03(Int.) MxPS=  32 Ivl=6ms
>>
>>
>> when I do a 'cat /dev/ttyUSB0' I get basically nothing as output.  Some
>> Internet searching tells me to comment out line 408 (that haas the code
>> 'cypress_set_dead(port);') in the cypress_m8.c file and recompile the
>> module.  At this point I am stuck.  I found the file and there is the
>> appropriate line at position 408, I can comment it out but do not need
>> to know what to do to recompile this module.
>>
>> Any assistance would be greatly appreciated!
>>
>> Paul Olson
>>
>>
>>     
> Before you go to the trouble of re-compiling the module, you may
> want to check things out a bit more. As far as I know, none of the
> GPS modules will give you anything when using "cat <device>". This
> is because you have to set the serial port up, (correct baud rate,
> data bits, etc.) and then send it the commands to start it up.
>
> Do you have the gpsd package installed? It should work just fine
> with this unit. I am not sure if the latest gpsd package will handle
> hot-plugging this GPS, or if you will have to start gpsd yourself,
> and tell it to use this port. I have a package that adds some stuff
> to udev that I use to manage gpsd, and auto add/remove hot-plugged
> devices. I am not sure if it is the official repo though. (I have a
> different USB GPS, but I grabbed the device infor from the old gpsd
> hotplug code.)
>
> Mikkel
>   
Thanks for the help so far, Mikkel!

when I launch gpsd using:

gpsd -f /dev/ttyUSB0 -n -N

and then try to launch xgps in another terminal window with:

xgps localhost:2947

the xgps application shows a status of 'UNKNOWN' and a GPS Type of 
'unknown'.  The other fields display 'n/a' and the status bar says 'no 
data arriving'.

At this point it is not working, but it may be the case that I have the 
wrong command-line options...

Thanks again for the assistance...

Paul





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