[ts-7000] Re: Help connecting to GPS on com2

["prcarnly" <>]

I am a newbie to the 7250 as well as to linux. I need to read a rs232 
signal from my com2 port and have tried lots of code from online 
guides with no sucess so I turned to this group and found this post 
and have used the code displayed below. I have even commented out the 
getty. I am getting a -1 read error when I run the code. The port 
opens, but res returns a -1. Can anyone help with what may be going 
on with this or what this error means? I've searched online and have 
not found this error. Thank you in advance for any help.

Renee


--- In  Jim Jackson <> wrote:
>
> 
> 
> 
> On Sat, 7 Oct 2006, Rob wrote:
> 
> > I have been trying to connect to a Garmin GPS and just echo the 
NMEA
> > data to the console for a proof of concept.  While I think I am 
getting
> > closer it still just shows zero for the data received.  I have 
looked at
> > many examples here and the code is starting to look correct.  
Also if I
> > log onto the board using COM2 it asks for a password ???
> 
> You say you can login to "com2". That means you have a "getty" 
running on
> that line too. You will need to stop the getty process so your 
program has
> sole access to the port.
> 
> comment out the line in /etc/inittab that tells init to run getty on
> /dev/ttyAM1, then send init a HUP signal to reread the inittab file
> (kill -1 1)
> 
> >
> > Here is the code and the settings are the standard ones on the 
Debian
> > release (using the CF card and Debian)
> >
> > #include <stdio.h>
> > #include <termios.h>
> > #include <sys/types.h>
> > #include <sys/stat.h>
> > #include <fcntl.h>
> >
> >
> > int open_port(char* device_name)
> > {
> >     int file_id;
> >
> >     file_id = open(device_name, O_RDONLY | O_NOCTTY | O_NDELAY);
> >     if(file_id == -1)
> >     {
> >       printf("Failed to open device\n");
> >     }
> >     return file_id;
> > }
> >
> > int read_port(int file_id)
> > {
> >     char            buffer[512];
> >     int             count=0;
> >     int             lines = 0;
> >
> >     while(lines < 50)
> >     {
> >             read(file_id, buffer, count);
> >             lines++;
> >             /* Add terminator and print if non-zero */
> >             if(count > 0)
> >             {
> >                     buffer[count] = '\0';
> >                     printf("Line %d has %d characters\n", lines, 
count);
> >                     printf("%s\n", buffer);
> >             }
> >             else
> >             {
> >                     printf("Zero characters read\n");
> >             }
> >     }
> > }
> >
> > void port_configuration(int file_id)
> > {
> >     struct termios options;
> >     int            x;
> >
> >     tcgetattr (file_id, &options);
> >     printf("speed in %d out %d\n", options.c_ispeed, 
options.c_ospeed);
> >     printf("mode in %d out %d\n", options.c_iflag, 
options.c_oflag);
> >     printf("control flag %d\n", options.c_cflag);
> >     printf("local flag %d\n", options.c_lflag);
> >
> >     cfsetispeed(&options, B4800);
> >     cfsetospeed(&options, B4800);
> >     options.c_cflag = 2096;
> >     options.c_lflag = 4;
> >     options.c_oflag = 0;
> >     options.c_cflag |= (CLOCAL | CREAD);
> >     options.c_cflag &= ~PARENB;
> >     options.c_cflag &= ~CSTOPB;
> >     options.c_cflag &= ~CSIZE;
> >     options.c_cflag |= CS8;
> >     options.c_cflag &= ~CRTSCTS;
> >     tcsetattr (file_id, TCSANOW, &options);
> > }
> >
> > int main(int argc, char* argv[])
> > {
> >     int file_id;
> >
> >     /* Check the command */
> >     if(argc < 2)
> >     {
> >             printf("serial_tester <device>\n");
> >             return 0;
> >     }
> >     /* Open the port */
> >     printf("Opening device %s\n", argv[1]);
> >     file_id = open_port(argv[1]);
> >     /* Get port configuration */
> >     port_configuration(file_id);
> >     /* Set the port to non bolocking and Read the port */
> >     read_port(file_id);
> >     close((file_id));
> > }
> >
> >
> > Thanks for helping a newbie out.  Also I am open to any suggested 
reading that would
> > have let me find it myself.
> >
> >
> >
> >
> >
> >
>




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