Ubuntu Serial Test

1>. Virtual serial port test (http://www.xappsoftware.com/wordpress/2013/10/07/using-virtual-serial-ports-on-linux-ubuntu/?) GOBACK=%2EGDE_65688_MEMBER_5792872722853814274#%21)
Virtual serial port tool is available under Windows. Ubuntu also has the following:
Install Virtual serial port:

sudo apt-get install Socat

Create and connect 2 virtual serial ports

The path is under:/dev/pts.
There is no before the creation, you can use the ls/dev/pts test.
Open a new terminal and enter the command to open the virtual serial 5:

# sudo CAT/DEV/PTS/5

Open another terminal, send the data to the virtual serial 6, because 6 and 5 are interlinked, so 5 will receive the data.

# sudo echo "Hello World" >/DEV/PTS/6

That's all.
See figure below:

The virtual serial port is not created, of course, see the following figure:

2> and Minicom Communications.
See figure below:
(Minicom Open the virtual serial 7, to the virtual serial 28 send characters, Minicom will receive)

3>
Finally use their own code to test, the serial source is as follows (reference http://blog.csdn.net/u010925447/article/details/72763052):
Uart.c

#include <stdio.h>/* standard input/output definition */#include <stdlib.h>//Standard function library definition */#include <unistd.h>      /*unix standard function definition */#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> /* File Control definition */#include <termios.h>/*ppsix terminal control definition/#include <errno.h>/* error number Definition *//************ /#define FALSE-1 #define TRUE 0/************************
    /#if 0 int main (void) {int fd;
struct Termios Opt;
    Tcgetattr (FD, &opt);     Cfsetispeed (&opt,b19200);
    /* Set to 19200bps*/cfsetospeed (&opt,b19200);
    Tcsetattr (fd,tcanow,&opt);
    * Read and write to open the serial port/fd = open ("/dev/ttys0", O_RDWR); if ( -1 = = FD) {perror ("hint Error").
    "); #endif/** * @brief Set serial communication rate * @param FD type int open serial file handle * @param speed type int serial speed * @return void */INT Speed_arr[] = {B38400,B19200, B9600, B4800, B2400, B1200, B300, B38400, B19200, B9600, B4800, B2400, B1200, B300,};
int name_arr[] = {38400, 19200, 9600, 4800, 2400, 1200, 300, 38400, 19200, 9600, 4800, 2400, 1200, 300,}; 
 void Set_speed (int fd, int speed) {int i; 
 int status;
 struct Termios Opt; 
 Tcgetattr (FD, &opt);  for (i= 0;  I < sizeof (Speed_arr)/sizeof (int);     
   i++) {if (speed = = Name_arr[i]) {Tcflush (fd, Tcioflush);  
   Cfsetispeed (&opt, speed_arr[i]);   
   Cfsetospeed (&opt, speed_arr[i]);  
   Status = Tcsetattr (FD, Tcsanow, &opt);  
    if (status!= 0) {perror ("tcsetattr fd1");     
   Return   
  } tcflush (Fd,tcioflush); /** * @brief set serial data bits, stop bits and parity bits * @param FD type int open serial file handle * @param databits type int data bits are 7 or 8 * @pa  RAM stopbits type int stop bit value is 1 or 2 * @param parity type int parity type value is n,e,o,,s/int set_parity (int fd,int databits,int Stopbits,int parity) {struct TERmios options;     
      if (tcgetattr (fd,&options)!= 0) {perror ("Setupserial 1");  
     return (FALSE); 
     } options.c_cflag &= ~csize; 
      Switch (databits)/* Set the number of data digits/{case 7:options.c_cflag |= CS7;
     Break
      Case 8:options.c_cflag |= CS8;   
     Break default:fprintf (stderr, "Unsupported data Sizen");  
     return (FALSE);   Switch (parity) {case ' n ': Case ' n ': Options.c_cflag &= ~parenb;     /* Clear parity Enable */Options.c_iflag &= ~INPCK;  
     /* Enable Parity checking * * break; Case ' O ': Case ' o ': Options.c_cflag |= (parodd | PARENB);             /* Set to the Magic Magic Test/Options.c_iflag |= INPCK;  
     /* disnable Parity checking * * break;     Case ' E ': Case ' e ': Options.c_cflag |= Parenb;   /* Enable Parity * * Options.c_cflag &= ~parodd; /* Conversion to even-parity */options.c_iFlag |= INPCK;
     /* disnable Parity checking * * break;
      Case "s": Case ' s ':/*as no parity*/options.c_cflag &= ~parenb;  
     Options.c_cflag &= ~cstopb;break;    
      default:fprintf (stderr, "Unsupported Parityn");  
     return (FALSE);  
      /* Set Stop bit */switch (stopbits) {case 1:options.c_cflag &= ~CSTOPB;  
     Break  
        Case 2:options.c_cflag |= CSTOPB;
     Break  
       default:fprintf (stderr, "Unsupported Stop Bitsn"); 
    return (FALSE); 
    }/* Set input parity option */if (parity!= ' n ') options.c_iflag |= inpck;
    Tcflush (Fd,tciflush); Options.c_cc[vtime] = 150; /* Set timeout seconds*/options.c_cc[vmin] = 0;  /* Update the options and do it now/if (tcsetattr (fd,tcsanow,&options)!= 0) {perror ("setupserial   
     3 ");  
    return (FALSE);  
return (TRUE); /** code Description: Using the serial port test, the number of sentIt is a character, but does not send a string ending symbol, so after receiving, the end symbol is appended.
I tested the use of SCM to send data to the second serial port, the test passed.         * * int Opendev (char *dev) {int fd = open (Dev, O_RDWR); //| O_noctty |
  O_ndelay if ( -1 = = FD) {perror ("Can" "T Open serial Port");  
 return-1;
else return FD;
 int main (int argc, char **argv) {int fd;
 int nread;
 Char buff[512]={0}; Char *dev = "/DEV/PTS/7";//"/DEV/TTYS1";
 Serial port Two fd = Opendev (dev);
 Set_speed (fd,19200);
  if (set_parity (fd,8,1, ' N ') = = FALSE) {printf ("Set Parity Errorn");
 Exit (0); 
 while (1)//loop reads data {while (nread = read (FD, Buff,)) >0) {printf ("nlen=%d\n", nread);   
  Buff[nread+1] = ' the ';   
 printf ("rx:%s\n", buff);  
 }//close (FD);
Exit (0);    }//write:char buffer[1024];int Length;int nbyte;nbyte = write (fd, buffer, Length)//read:char Buff[1024];int Len;int readbyte = read (Fd,buff,len);

Uart.c
Compilation:
gcc uart.c-o uart
Execution (this serial port is open with virtual serial port 7):
./uart
Then send the data to the virtual serial port 28, the UART program will print the length and data received. Just the length seems wrong ...
The following figure: