Differences

This shows you the differences between two versions of the page.

--- using_the_serial_port_march_2013 [2013/03/14 11:00] – created tomgee
+++ using_the_serial_port_march_2013 [2013/03/14 11:35] (current) – tomgee
@@ Line 1: / Line 1: @@
+===== USE THE SERIAL PORT IN SOFTWARE =====
+By default, the serial port is configured as a console port for interacting with the Linux OS shell.  If you want to use the serial port in a software program, you must disable the OS from using this port.
 ===== Serial Library =====
 WiringPi includes a simplified serial port handling library. It can use the on-board serial port, or any USB serial device with no special distinctions between them. You just specify the device name in the initial open function.
@@ Line 56: / Line 59: @@
 man tcgetattr
+===== Sample Program =====
+/*
+ * serialTest.c:\\
+ *	Very simple program to test the serial port. Expects\\
+ *	the port to be looped back to itself\\
+ *\\
+ */\\
+#include <stdio.h>\\
+#include <string.h>\\
+#include <errno.h>\\
+#include <wiringPi.h>\\
+#include <wiringSerial.h>\\
+int main ()
+{
+  int fd ;
+  int count ;
+  unsigned int nextTime ;
+  if ((fd = serialOpen ("/dev/ttyAMA0", 115200)) < 0)
+  {
+    fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+  if (wiringPiSetup () == -1)
+  {
+    fprintf (stdout, "Unable to start wiringPi: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+  nextTime = millis () + 300 ;
+  for (count = 0 ; count < 256 ; )
+  {
+    if (millis () > nextTime)
+    {
+      printf ("\nOut: %3d: ", count) ;
+      fflush (stdout) ;
+      serialPutchar (fd, count) ;
+      nextTime += 300 ;
+      ++count ;
+    }
+    delay (3) ;
+    while (serialDataAvail (fd))
+    {
+      printf (" -> %3d", serialGetchar (fd)) ;
+      fflush (stdout) ;
+    }
+  }
+  printf ("\n") ;
+  return 0 ;
+}
+===== Hardware Level Converter Hookup =====
+{{:raspi-rs232-schematic2.png|}}