Re: [Gumstix-users] Trouble connecting to a Bluetooth GPS reciever

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channel 2 looks wrong. it's usually 1, but you can use sdptool to check.

On Wed, Apr 2, 2008 at 8:49 PM, Zack Schilling <za...@sn...> wrote:
> I understand that some of my setup could be simpler (I tried it the
>  way you described and got basically the same result). GPSd cannot
>  connect to this device, nor can "sertest", a serial test program off
>  the Wiki. What should the inside of my rfcomm file look like? Right
>  now, it looks like this:
>
>  rfcomm0 {
>          listen yes;
>
>          # Bluetooth address of the device
>          device hci0;
>
>          # RFCOMM channel for the connection
>          channel 1;
>
>          # Description of the connection
>          comment "Gumstix Serial Console";
>  }
>
>  rfcomm1 {
>         bind yes;
>         device 00:0D:B5:34:B1:12;
>         channel 2;
>         comment "GPS";
>  }
>
>
>  Does the passkey go in here somewhere? Do I have it set up incorrectly?
>
>
>
>
>  On Apr 2, 2008, at 10:22 PM, Brad Midgley wrote:
>
>  > Zach
>  >
>  > Some of your approach could be simpler. You don't need to do anything
>  > with sdp since you are a client to the gps.
>  >
>  > Put your rfcomm bindings in /etc/bluetooth/rfcomm.conf.
>  >
>  > Use gpsd and point it at /dev/rfcomm1 or whatever using /etc/default/
>  > gpsd.
>  >
>  > You can make gpsd hold the connection up by running something like
>  > "gpspipe -r" in the background. Otherwise the bt connection is made on
>  > demand and your gps may time and turn off the bt radio.
>  >
>  > The c api for gpsd is straightforward and isolates you from nmea
>  > parsing.
>  >
>  > Brad
>  >
>  > On Wed, Apr 2, 2008 at 4:41 PM, Zack Schilling <za...@sn...> wrote:
>  >> This is a long read, I'm sorry for that, but I wanted to be very
>  >> complete. Please read all of it.
>  >>
>  >> I'm working on a project where I'd like to connect a waysmall 400xm-
>  >> bt
>  >> to a Bluetooth GPS receiver. The receiver is a G-sat model that
>  >> requires a passkey for connection ("0000"). I'm trying to connect it
>  >> to the gumstix computer as a bluetooth serial device. I then want to
>  >> use this serial device in a C program I'm writing.
>  >>
>  >> I seem to be having trouble getting this all working and I'm not
>  >> exactly sure where the problem is, I'm new to all of this. Basically,
>  >> this is what I have:
>  >>
>  >> I want to keep the bluetooth terminal and this new device at the same
>  >> time, so I have the following in a startup script:
>  >>
>  >>         sdptool add --channel=2 SP
>  >>         sdptool setattr 0x10000 0x100 "Ch 1 Serial (getty)"
>  >>         sdptool setattr 0x10001 0x100 "Ch 2 Serial (GPS)"
>  >>
>  >> This seems to be working. I can see it run at startup and it makes
>  >> the
>  >> new port for me.
>  >>
>  >> Next, I have a script that binds the bluetooth device to /dev/rfcomm1
>  >> before my program runs. I simply run the command:
>  >>
>  >>        # rfcomm bind 1 00:0D:B5:34:B1:12
>  >>        # rfcomm
>  >>        rfcomm1: 00:0D:B5:34:B1:12 channel 1 clean
>  >>
>  >> As you can see, the port binds and all that. I can even  ping the
>  >> device (l2ping 00:0D:B5:34:B1:12) with 0% loss. But when I run my C
>  >> program, the trouble starts.
>  >>
>  >> The program is supposed to read from the GPS, run a few calculations,
>  >> and send off the result over wired serial (ttyS2) to a nearby PIC.
>  >> The
>  >> wired serial port part works fine. I've tested it independently with
>  >> hardcoded data. However, the minute I try to use basically the same
>  >> code to connect to and test the GPS, it all goes downhill.
>  >>
>  >> The GPS setup code follows:
>  >>
>  >> // Open the GPS serial port.
>  >>
>  >>     if (( gpsPort = open( "/dev/rfcomm1", O_RDWR | O_EXCL )) < 0 )
>  >>     {
>  >>                fprintf( stderr, "Unable to open GPS serial port: %s
>  >> \n",
>  >> strerror( errno ));
>  >>                exit( 2 );
>  >>     }
>  >>
>  >> // Get the attribute structure of the port we just opened to set up
>  >> the baud rate and other details.
>  >>     if ( tcgetattr( gpsPort, &attr ) < 0 )
>  >>     {
>  >>         fprintf( stderr, "Failed initialize GPS serial port: %s\n",
>  >> strerror( errno ));
>  >>         exit( 3 );
>  >>     }
>  >>
>  >> attr.c_iflag = 0; // No Software Flow Control
>  >> attr.c_oflag = 0;
>  >> attr.c_cflag = CLOCAL | CREAD | CS8;
>  >> attr.c_lflag = 0;
>  >> attr.c_cc[ VTIME ] = 2; // timeout in tenths of a second
>  >> attr.c_cc[ VMIN ] = 1;
>  >>
>  >> cfsetispeed( &attr, B38400 );
>  >> cfsetospeed( &attr, B38400 );
>  >>
>  >> // Apply the attribute changes.
>  >>     if ( tcsetattr( gpsPort, TCSAFLUSH, &attr ) < 0 )
>  >>     {
>  >>         fprintf( stderr, "Failed to setup GPS serial port: %s\n",
>  >> strerror( errno ));
>  >>         exit( 4 );
>  >>     }
>  >>
>  >> // Done setting up GPS.
>  >>
>  >> fprintf( stdout, "System Online.\n\n");
>  >>
>  >>
>  >>
>  >> Except I never get to the "System Online" part. I get a segmentation
>  >> fault. Ugh, it couldn't be more vague. Though some basic debugging, I
>  >> found the program is never getting past this function:
>  >>
>  >> open( "/dev/rfcomm1", O_RDWR | O_EXCL )
>  >>
>  >> When I check rfcomm after the program has run, I see:
>  >>
>  >>        # rfcomm
>  >>        rfcomm1: 00:0D:B5:34:B1:12 channel 1 closed
>  >>
>  >> If I run the program again, I get this error:
>  >>
>  >>        Unable to open GPS serial port: Device or resource busy
>  >>
>  >> Ok, not exactly unexpected. I can unbind, bind and run again and I'll
>  >> get the segmentation fault again. Any advice would be appreciated. Am
>  >> I missing something obvious? I replaced my default Gumstix bluetooth
>  >> passkey of 1234 with 0000, should I be doing something else to
>  >> connect? Could it be my compiler settings? Other wired serial ports
>  >> open, read, write and otherwise work perfectly fine. In fact, if I
>  >> replace /dev/rfcomm1 with /dev/ttyS2 in my code, it runs fine. I've
>  >> been stuck on this for 2 days and it's so frustrating.
>  >>
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>  >
>  >
>  >
>  > --
>  > Brad
>  >
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-- 
Brad