C Exmaple

You can write the Serial port as the follow demo, the linux inode for the CORE9G25 board is as follow:

For the C demo, please see the follow word, you can find it at hte CD://linux/example/serial/comtest.c,

#include "stdio.h"     
#include "string.h"    
#include "unistd.h"    
#include "fcntl.h"     
#include "errno.h"     
#include "sys/types.h"
#include "sys/stat.h"
#include "stdlib.h"
#include "stdarg.h"
#include "termios.h"
 
int main(void) {
    char txBuffer[10];
    char rxBuffer[10];
    int fd;
    struct termios tty_attributes;
 
    if ((fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY|O_NONBLOCK))<0) {
        fprintf (stderr,"Open error on %s\n", strerror(errno));
        exit(EXIT_FAILURE);
    } else {
        tcgetattr(fd,&tty_attributes);
 
        // c_cflag
        // Enable receiver
        tty_attributes.c_cflag |= CREAD;        
 
        // 8 data bit
        tty_attributes.c_cflag |= CS8;          
 
        // c_iflag
        // Ignore framing errors and parity errors. 
        tty_attributes.c_iflag |= IGNPAR;       
 
        // c_lflag
        // DISABLE canonical mode.
        // Disables the special characters EOF, EOL, EOL2, 
        // ERASE, KILL, LNEXT, REPRINT, STATUS, and WERASE, and buffers by lines.
 
        // DISABLE this: Echo input characters.
        tty_attributes.c_lflag &= ~(ICANON);     
 
        tty_attributes.c_lflag &= ~(ECHO);      
 
        // DISABLE this: If ICANON is also set, the ERASE character erases the preceding input  
        // character, and WERASE erases the preceding word.
        tty_attributes.c_lflag &= ~(ECHOE);     
 
        // DISABLE this: When any of the characters INTR, QUIT, SUSP, or DSUSP are received, generate the corresponding signal. 
        tty_attributes.c_lflag &= ~(ISIG);      
 
        // Minimum number of characters for non-canonical read.
        tty_attributes.c_cc[VMIN]=1;            
 
        // Timeout in deciseconds for non-canonical read.
        tty_attributes.c_cc[VTIME]=0;           
 
        // Set the baud rate
        cfsetospeed(&tty_attributes,B115200);     
        cfsetispeed(&tty_attributes,B115200);
 
        tcsetattr(fd, TCSANOW, &tty_attributes);
 
        txBuffer[0]='A';
        write(fd,txBuffer,1);
 
        // Read a char
        if (read(fd,&rxBuffer,1)==1) {
            printf("%c",rxBuffer[0]);
            printf("\n");
        }   
    }   
 
    close(fd);  
    return EXIT_SUCCESS;
}