Hello everybody:

I need to drive the serial port. I have been reading about some functions to do this in C and i found this:

write(fd, "a", 1);

This function returns -1 on error or the number of bytes transmitted in success.

My problem is that what I need to send by serial port an .hex file. So I have read the .hex file with:

int car;
char nombre[13]=PWM.hex"; // File which will bi open
FILE *buffer;
buffer = fopen( nombre, "r" );
printf( "Fichero: %s -> ", nombre );
if( buffer )
printf( "File open\n" );
else
{
printf( "File is not open \n" );
return 1;
}
car=fgetc(buffer);

In car I have the first character of the .hex file. When I show this character with:

printf("%c", car);

every thing is good but I don´t know how to send this character by the serial port, the function:

write(fd, car, 1);

doesn´t work. This function returns -1 meaning that an error occurs. I think that this is because the data type doesn´t match. But who can I make this work well?

Can anybody tell me what’s wrong or which function should I use instead of write????.

before the code that i have show below i have open the serial port file so this is not the problem.

Tanks a lot.

First of all, the easiest way to output a file through a serial device is to use (This assumes that you're not bothered about the speed of the serial device).

You can find out what the error is by #include-ing the files errno.h and string.h. Then replace your call to write(fd,car,1) with:This will output the error message caused by the write command.

Hi, you're sending a intel hex image file to a board?
The way I do it is through kermit.
# kermit
set port ttyS0
set speed 9600
set flow none
set carrier off
transmit filename.hex
close
quit

I also have a serial library I wrote if you still want to do it in C.
I don't know how to get it to you, you can try emailing me.