wiringpi教程5 读串口serialRead.c

znck007

/*
* serialRead.c:
*    Example program to read bytes from the Serial line
*
*/

#include <stdio.h>
#include <string.h>
#include <errno.h>

#include <wiringSerial.h>

int main ()
{
  int fd ;
//看解释

//int serialOpen (char *device, int baud) ;

//This opens and initialises the serial device and sets the baud rate. It sets the port into “raw” mode //(character at a time and no translations), and sets the read timeout to 10 seconds. The return value is the file //descriptor or -1 for any error, in which case errno will be set as appropriate

// 没有接到设备就是-1 超时为10秒

  if ((fd = serialOpen ("/dev/ttyAMA0", 115200)) < 0)
  {
    fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno)) ;
    return 1 ;
  }

// Loop, getting and printing characters

  for (;;)
  {

//

//int serialGetchar (int fd) ;

//Returns the next character available on the serial device. This call will block for up to 10 seconds if no data //is available (when it will return -1)

    putchar (serialGetchar (fd)) ;
    fflush (stdout) ;
  }
}