Revision 5:837b2680bebb, committed 2021-04-24

Comitter:

timo_k2

Date:

Sat Apr 24 15:28:36 2021 +0000

Parent:

4:4118d38b68e1

Commit message:

Sends a series of four UDP messages with different number of bytes. For each one prints the round trip delay. The number of bytes has no effect on the round trip delay, the latency.

Changed in this revision

--- a/main.cpp	Sun Jan 17 19:09:05 2021 +0000
+++ b/main.cpp	Sat Apr 24 15:28:36 2021 +0000
@@ -9,7 +9,7 @@
  * An other microcontroller with "Round trip echo" will be needed. 
  * NXP FRDM-K64F used for testing.
  *   
- * Timo Karppinen 17.1.2021
+ * Timo Karppinen 24.4.2021
  ***********************************/
 #include "mbed.h"
 #include "EthernetInterface.h"
@@ -17,7 +17,7 @@
 
 #define REMOTE_PORT 5000
 #define LOCAL_PORT 5001
-#define BUFF_SIZE 128  // test with 32, 128, 512, etc
+#define BUFF_SIZE 512  // test with 32, 128, 512
 
 //Network interface
 EthernetInterface net;
@@ -26,7 +26,7 @@
     Thread recv_thread;
 
 // UDP
-SocketAddress clientUDP;  // Client on remote device
+SocketAddress clientUDP;  // Client on remote device. IP address from incoming message.
 UDPSocket serverUDP;   // UDP server in this device
 
 //NTP server is a time server used for delivering timing information for networks.
@@ -40,14 +40,14 @@
 // Functions
 //time_t getNTP();
 void udpReceive( void );
-void udpSend( void );
+void udpSend( int ii );
 
 DigitalIn sw2(SW2);     // sw2 on K64F, button pressed = FALSE
 DigitalOut led2(LED2);  // RGB LED on K64F, FALSE = Green
 int sw2state = 0;
 int sw2old = 1;
 
-char in_data[BUFF_SIZE];
+char in_data[BUFF_SIZE]; // 512 taken as max message size
 int newDatagram = 0;
 int newDatagramOld = 0;
 //time_t timeNTP = 0;
@@ -59,8 +59,8 @@
     printf("\nRound trip delay in UDP messaging (using Ethernet)\n");
     
     //Bring up the network interface
-    //eth.set_network(IP_Adress,GATEWAY,MASK); // leave out if using DHCP
-    net.set_network("192.168.1.10","192.168.1.1","255.255.252.0");
+    //eth.set_network(IP_Adress,MASK, GATEWAY); // leave out if using DHCP
+    net.set_network("192.168.1.10","255.255.252.0","192.168.1.1");
     net.connect();
     
     // Show network address
@@ -89,46 +89,53 @@
   
     while(1) {  
     sw2state = sw2.read();
-    printf( "\nsw2state is  %d\n", sw2state); // Printing showing "I am alive".
+    printf( "\nsw2  %d  -  Push for sending Echo Request\n", sw2state); 
     
     if((sw2state == 0)&&(sw2state != sw2old)) {   // Note! Checking for FALSE sw
-        led2.write(1);
+      led2.write(1);
+      for ( int i=0; i < 5; ++i){
         armedFor.reset();   // reset timer to zero
         stopwatch.reset();   // reset stopwatch timer to zero
         //timeNTP = getNTP();
+        ThisThread::sleep_for(10ms); //time for resetting
         armedFor.start();
         //stopwatch.start();  // moved to udpSend subroutine
-        udpSend();
+        udpSend(i);
         
     
         // Start polling for the incoming "Echo" UDP datagram   
-        while ( armedFor.elapsed_time().count() < 8000000 ){
+        while ( armedFor.elapsed_time().count() <2000000 ){
             if((newDatagram == 1)&&(newDatagram != newDatagramOld)){
                 stopwatch.stop(); 
                 char firstChar;
                 firstChar = in_data[0];
-                printf( "firstChar: %s\n", &firstChar);
+                printf( "\nfirstChar: %s\n", &firstChar);
+                ThisThread::sleep_for(120ms); // waiting for print buffer, 100 ms was just too short
                 for (int k =0; k < BUFF_SIZE; k++){
                     in_data[k] = 0;
                     } 
-            }
+                // printing for testing. Replace with writing once to a SD memory card.
+                //printf("Measured at ( day month hour.min.sec year ) %s\r\n", ctime(&timeNTP));
+                printf("The time taken was %llu microseconds\n", stopwatch.elapsed_time().count());
+            } // if new datagram
             newDatagramOld = newDatagram; //Reading the stopwatch once only 
-            newDatagram = 0;   
-        }
+            newDatagram = 0;  
+        } // while armed
+        ThisThread::sleep_for(70ms); // Delay of 10ms + 120ms + 70ms = 200ms
+      } //for i loop
         
         // printing for testing. Replace with writing once to a SD memory card.
         //printf("Measured at ( day month hour.min.sec year ) %s\r\n", ctime(&timeNTP));
-        printf("The time taken was %llu microseconds\n", stopwatch.elapsed_time().count());
-        
-    }
+        //printf("The time taken was %llu microseconds\n", stopwatch.elapsed_time().count()); 
+    } // if sw2
     sw2old = sw2state; // Once only with pushing the button as long as you like.
     led2.write(0);
     armedFor.stop();
     stopwatch.stop();  // Stop the stopwatch if we did not receive the echo.
     
     ThisThread::sleep_for(1000ms);
-    }
-}
+    } // while loop
+} // main
 
 // The functions
   
@@ -152,24 +159,38 @@
 {
     int bytes;
     while(1) {
-        bytes = serverUDP.recvfrom(&clientUDP, &in_data, BUFF_SIZE);
+        bytes = serverUDP.recvfrom(&clientUDP, &in_data, 512); // 512 as largest possible
         newDatagram = 1;    // set this before using time for printing
-        ThisThread::sleep_for(400ms); // waiting for the print buffer
-        printf("\n");
+        ThisThread::sleep_for(50ms); // waiting for the print buffer
         printf("bytes received: %d\n",bytes);
         printf("string: %s\n",in_data);
         printf("client address: %s\n", clientUDP.get_ip_address());
-        printf("\n");
- 
         }
 }
 
-void udpSend()
+void udpSend(int ii)
 {
-        char out_data[BUFF_SIZE];
-        
-        snprintf(out_data, BUFF_SIZE, "UDP message for getting the Echo" );
-        printf("Sending out: %s\n", out_data);
+        int BUFF_SIZE_NOW;
+        switch(ii){
+            case 0:
+            BUFF_SIZE_NOW = BUFF_SIZE/16;
+            break;
+            case 1:
+            BUFF_SIZE_NOW = BUFF_SIZE/8;
+            break;
+            case 2:
+            BUFF_SIZE_NOW = BUFF_SIZE/4;
+            break;
+            case 3:
+            BUFF_SIZE_NOW = BUFF_SIZE/2;
+            break;
+            case 4:
+            BUFF_SIZE_NOW = BUFF_SIZE;
+            break;
+        }
+        char out_data[BUFF_SIZE_NOW];
+        snprintf(out_data, BUFF_SIZE_NOW, "UDP message for getting the Echo" );
+        printf("\nSending out: %s\n", out_data);
         printf("with %d" , sizeof(out_data));
         printf(" data bytes in UDP datagram\n");
         clientUDP.set_port(REMOTE_PORT);