send text to serial port

QNX Newsgroups (Archives) qnx.qnx4
1

I wonder if anyone could tell me how I can send a text to the serial port.

I’m writing a C program for a sensor that periodically takes reading and
would like to output the readings on the serial port. I was thinking of
initialising the port with system(“stty baud=115200 </dev/ser2”); etc and
then outputting a formatted datastring using a fprintf command.
Initialisation is ok but I can’t manage to get the fprintf to work! I can
output a file to the serial port like system(“cp testfile.txt /dev/ser2”);
however this is not really what I want as the readings I want to output
constantly changes.

Thanks a lot for any help

Regards
Lars

2

Lars Skade wrote:

I wonder if anyone could tell me how I can send a text to the serial port.

I’m writing a C program for a sensor that periodically takes reading and
would like to output the readings on the serial port. I was thinking of
initialising the port with system(“stty baud=115200 </dev/ser2”); etc and
then outputting a formatted datastring using a fprintf command.
Initialisation is ok but I can’t manage to get the fprintf to work! I can
output a file to the serial port like system(“cp testfile.txt /dev/ser2”);
however this is not really what I want as the readings I want to output
constantly changes.

Thanks a lot for any help

Regards
Lars


Lars,

I have an application that writes ascii characters to a stepper motor
controller. I start by opening the serial port

port = open("/dev/ser1", O_RDWR);

then using write to output text

write(port, str, strlen(str);

I test by connecting a VT100 terminal to the serial port to look at the
output.

3

John McClurkin <jwm@lsr.nei.nih.gov> wrote:
JM > Lars Skade wrote:

I wonder if anyone could tell me how I can send a text to the serial port.

I’m writing a C program for a sensor that periodically takes reading and
would like to output the readings on the serial port. I was thinking of
initialising the port with system(“stty baud=115200 </dev/ser2”); etc and
then outputting a formatted datastring using a fprintf command.
Initialisation is ok but I can’t manage to get the fprintf to work! I can
output a file to the serial port like system(“cp testfile.txt /dev/ser2”);
however this is not really what I want as the readings I want to output
constantly changes.

Thanks a lot for any help

Regards
Lars


JM > Lars,

JM > I have an application that writes ascii characters to a stepper motor
JM > controller. I start by opening the serial port

JM > port = open("/dev/ser1", O_RDWR);

JM > then using write to output text

JM > write(port, str, strlen(str);

JM > I test by connecting a VT100 terminal to the serial port to look at the
JM > output.

I think the issue your up against is that fprintf() can buffer it’s output.
Use write() instead.

4

Or, you can call fflush() after fprintf() on the file pointer to flush the
data from the local buffer.

“Bill Caroselli” <qtps@earthlink.net> wrote in message
news:cpmqqk$a5f$2@inn.qnx.com…

John McClurkin <> jwm@lsr.nei.nih.gov> > wrote:
JM > Lars Skade wrote:
I wonder if anyone could tell me how I can send a text to the serial
port.

I’m writing a C program for a sensor that periodically takes reading and
would like to output the readings on the serial port. I was thinking of
initialising the port with system(“stty baud=115200 </dev/ser2”); etc
and
then outputting a formatted datastring using a fprintf command.
Initialisation is ok but I can’t manage to get the fprintf to work! I
can
output a file to the serial port like system(“cp testfile.txt
/dev/ser2”);
however this is not really what I want as the readings I want to output
constantly changes.

Thanks a lot for any help

Regards
Lars


JM > Lars,
JM > I have an application that writes ascii characters to a stepper motor
JM > controller. I start by opening the serial port

JM > port = open("/dev/ser1", O_RDWR);

JM > then using write to output text

JM > write(port, str, strlen(str);

JM > I test by connecting a VT100 terminal to the serial port to look at
the
JM > output.

I think the issue your up against is that fprintf() can buffer it’s
output.
Use write() instead.

5

thanks a lot everybody

problem sorted

Lars

“Kevin Miller” <kevin.miller@transcore.com> escribió en el mensaje
news:cpn0ce$ekj$1@inn.qnx.com…

Or, you can call fflush() after fprintf() on the file pointer to flush the
data from the local buffer.

“Bill Caroselli” <> qtps@earthlink.net> > wrote in message
news:cpmqqk$a5f$> 2@inn.qnx.com> …
John McClurkin <> jwm@lsr.nei.nih.gov> > wrote:
JM > Lars Skade wrote:
I wonder if anyone could tell me how I can send a text to the serial
port.

I’m writing a C program for a sensor that periodically takes reading
and
would like to output the readings on the serial port. I was thinking of
initialising the port with system(“stty baud=115200 </dev/ser2”); etc
and
then outputting a formatted datastring using a fprintf command.
Initialisation is ok but I can’t manage to get the fprintf to work! I
can
output a file to the serial port like system(“cp testfile.txt
/dev/ser2”);
however this is not really what I want as the readings I want to output
constantly changes.

Thanks a lot for any help

Regards
Lars


JM > Lars,
JM > I have an application that writes ascii characters to a stepper
motor
JM > controller. I start by opening the serial port

JM > port = open("/dev/ser1", O_RDWR);

JM > then using write to output text

JM > write(port, str, strlen(str);

JM > I test by connecting a VT100 terminal to the serial port to look at
the
JM > output.

I think the issue your up against is that fprintf() can buffer it’s
output.
Use write() instead.