this program can by compiled and run on several mbeds in a network. The mbed ID is automatically generated. This program is a small test to see if it works. To test the firmware you will need two ( or more ) mbed modules connected to the same network. Pin p5 should be connected with a push button to 3v3 and a resistor of 10k to ground. If the button is pressed the mbed will broadcast a message on ip 239, 192, 1, 100 on port 50000. All mbeds are listening to this ip address and port so they will pick up this message. If the message says MBED xyz LED ON, led1 will id on. If the message says MBED LED OFF, led1 will be off. It\\\'s that simple. So with one mbed you can turn the other mbeds led on or off.

Dependencies:   EthernetNetIf NTPClient_NetServices mbed

Revision:
3:3c33a398189e
Parent:
2:ae37f80efd23
diff -r ae37f80efd23 -r 3c33a398189e UDPSocketExample.cpp
--- a/UDPSocketExample.cpp	Wed Nov 24 23:46:38 2010 +0000
+++ b/UDPSocketExample.cpp	Mon Feb 14 08:10:14 2011 +0000
@@ -1,25 +1,5 @@
-#include "mbed.h"
-#include "EthernetNetIf.h"
-#include "UDPSocket.h"
-
-Serial pc(USBTX, USBRX);
-EthernetNetIf eth;
-UDPSocket udp;
-DigitalOut led(LED1);
-InterruptIn button(p5);
-Ticker AliveTicker;
+#include "system.h"
 
-// xxx will be replaced by LSByte of the IP address
-//
-// Message to let the other know we are alive
-char strAlive[15];
-
-char mebed_list[16];
-
-char ButtonPressed = 0;
-char SendAlive = 0;
-char mbed_id = 0;
-char mbed_client = 0;
 
 void Alive()         // ticker routine
 {
@@ -74,20 +54,29 @@
 int main() {
   char pos = 0;
   pc.baud(115200);
-  pc.printf("Ethernet...\n");
+  pc.printf("Ethernet...\n\r");
   EthernetErr ethErr = eth.setup();
   if(ethErr)
   {
-    pc.printf("Error %d in setup.\n", ethErr);
+    pc.printf("Error %d in setup.\n\r", ethErr);
     return -1;
   }
   pc.printf("  OK\n\r");
-
   IpAddr ethIp = eth.getIp();
   mbed_id = ethIp[3];
   sprintf( strAlive, "MBED %d ALIVE\0", mbed_id );
 
   pc.printf( "%s\n\r", strAlive );
+
+    /* Set up NTP */
+//    lcd.printf("Setting up NTP\n");
+    Host server(IpAddr(), 123, "0.uk.pool.ntp.org");
+    ntp.setTime(server);
+    /* Temporary variables for control loop */
+    time_t rtc_time = time(NULL);
+    int minute = -1;
+
+
   // set Alive Broadcast to 10 seconds
   AliveTicker.attach(&Alive, 10);  
   Host multicast(IpAddr(239, 192, 1, 100), 50000, NULL); //Join multicast group on port 50000
@@ -99,7 +88,7 @@
   udp.sendto( strAlive, strlen(strAlive), &multicast );
   
   button.rise(&button_pressed);
-  while(true)
+  while( 1 ) // Never Ending Story by Michael Ende
   {
     Net::poll();
     if ( SendAlive == 1 ) { udp.sendto( strAlive, strlen(strAlive), &multicast ); SendAlive = 0; }    // Send Alive Signal
@@ -113,6 +102,22 @@
       //pc.printf("%s\n", str);
       ButtonPressed = 0;
     }
+
+        /* Update current time */
+        rtc_time = time(NULL);
+        cTime = localtime(&rtc_time);
+        if (cTime->tm_min != minute)
+        {
+            pc.printf("*** %d:%d ***\n\r", cTime->tm_hour, cTime->tm_min);
+            minute = cTime->tm_min;
+            /* Update time from NTP server if it's midnight UTC */
+            if ((cTime->tm_min == 0) && (cTime->tm_hour == 0))
+            {
+                Host server(IpAddr(), 123, "0.uk.pool.ntp.org");
+                ntp.setTime(server);
+            }
+        }
+
   }