optty1.c

采用gpio口来控制串口扩展芯片的驱动和测试程序

#include <fcntl.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>


int main(int argc, char *argv[])
{
	int fd,size;
	struct termios oldt,newt;
	char buffer[256];
	
//Open Serial 2: COM2
	if (argc!=2)
		{
			printf("Usage : ./COM2 AT\n");
			exit(1);
		}
    printf ("Start input:\n");
    
    fd = open("/dev/ttyS1", O_RDWR|O_NOCTTY);
    
    printf("fd=%d \n",fd);
    
    printf ("Open COM 2 OK?\n");
    if(fd>=0)
    {
        tcgetattr(fd, &oldt);
        tcflush(fd, TCIOFLUSH);                         //Ensure there are nothing in buff when begin to transfer
        newt = oldt;
//        newt.c_cflag = B57600;               //It is wrong used.
	cfsetispeed (&newt, B115200);
	cfsetospeed (&newt, B115200);
        newt.c_cflag|CS8;
        newt.c_cflag|CLOCAL;
        newt.c_cflag|CREAD;
        newt.c_iflag=IGNPAR;
        newt.c_oflag=0;
        newt.c_lflag=0;
        newt.c_cc[VMIN]=1;
        newt.c_cc[VTIME]=20;
        //flusher data received but not read
        tcflush(fd,TCSANOW);
        //the change occur immediately
        tcsetattr(fd,TCSANOW,&newt);
        printf ("init  COM2 complete!\n");      
    }
    else
    	{perror ("Open serial failure");
         return -1;
	}

	printf("The AT Command is: %s\n",argv[1]);
	write(fd,argv[1],strlen(argv[1]+1));
	write(fd,"\r\n",2);

/*	size = read(fd,buffer,256);
	{
		buffer[size]='\0';
		printf("Return: %s\n",buffer);
	}

*/





//Save old Setting and Close Serial 2.
    tcsetattr(fd, TCSADRAIN, &oldt);
    close(fd);    

}