Diff: main.cpp

Revision:

0:2a5da7b2278c

Child:

1:961861d73841

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Nov 20 16:47:14 2020 +0000
@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2006-2020 Arm Limited and affiliates.
+ * SPDX-License-Identifier: Apache-2.0
+ ***********************************
+ * Round trip delay meter. Date and time is taken from a NTP server. 
+ * A microcontroller board with an Ethernet interface.
+ * An other microcontroller with "Round trip delay echo" will be needed. 
+ * NXP FRDM-K64F used for testing.
+ *   
+ * Timo Karppinen 20.11.2020
+ ***********************************/
+#include "mbed.h"
+#include "EthernetInterface.h"
+#include "ntp-client/NTPClient.h"
+
+#define REMOTE_PORT 5000
+#define LOCAL_PORT 5001
+#define BUFF_SIZE 128
+
+//Network interface
+EthernetInterface net;
+
+//Threads
+    Thread ntp_thread;
+    Thread recv_thread;
+    Thread send_thread; 
+    
+// UDP
+SocketAddress clientUDP;  // Client on remote device
+UDPSocket serverUDP;   // UDP server in this device
+
+
+//NTP server is a time server used for delivering timing information for networks.
+// Returns 32 bits for seconds and 32 bits for fraction of seconds. 
+//#define ntpAddress "2.pool.ntp.org"
+#define ntpAddress "time.mikes.fi"  // The VTT Mikes in Helsinki
+#define ntpPort 123
+
+// Functions
+time_t getNTP();
+void udpReceive( void );
+void udpSend( void );
+
+DigitalIn sw2(SW2);
+DigitalOut led2(LED2);
+int sw2state = 0;
+int sw2old = 1;
+
+char in_data[BUFF_SIZE];
+int newDatagram = 0;
+time_t timeNTP = 0;
+
+using namespace std::chrono;
+Timer stopwatch;
+    
+int main() {
+    printf("\nNTP Client example (using Ethernet)\r\n");
+    
+    //Bring up the network interface
+    net.connect();
+    
+    // Show network address
+    SocketAddress netAddress;
+    net.get_ip_address(&netAddress);
+    printf("\n\n NTPClient - UDPServer IP Address: %s\n", netAddress.get_ip_address() ? netAddress.get_ip_address():"None");
+    
+    // NTP client at ntp thread
+    ntp_thread.start(getNTP);
+    
+    // UDP server 
+    
+    serverUDP.open(&net);
+    int err = serverUDP.bind(LOCAL_PORT);
+    printf("Port status is: %d\n",err);
+    
+    recv_thread.start(udpReceive);
+    printf("Listening has been started at port number %d\n", LOCAL_PORT);
+    
+    send_thread.start(udpSend);
+    printf("Sending out demo data to port number %d", REMOTE_PORT);
+    printf(" has been started.\n");
+    printf("The IP will be taken from the incoming message\n");
+  
+
+    while(1) {  
+    sw2state = sw2.read();
+    printf( "sw2state is  %d\n", sw2state);
+    
+    if((sw2state == 0)&&(sw2state != sw2old)) {
+        led2.write(0);
+        stopwatch.reset();   // reset stopwatch timer to zero
+        timeNTP = getNTP();
+        stopwatch.start();
+        udpSend();
+        
+    
+        // Start polling for the incomening "echo" UDP datagram   
+        while ( stopwatch.elapsed_time().count() < 8000000 ){
+        if(newDatagram == 1){
+            char firstChar;
+            firstChar = in_data[0];
+            if (firstChar == 83){    // ASCII symbol 83 = "S" 
+                stopwatch.stop();
+                }
+            newDatagram = 0;
+            }
+        for (int k =0; k < BUFF_SIZE; k++){
+            in_data[k] = 0;
+            }
+        }
+    }
+    sw2old = sw2state; // Once only with pushing the button as long as you like.
+    led2.write(1);
+    stopwatch.stop();  // Stop the stopwatch if we did not receive the echo.
+    ThisThread::sleep_for(10000ms);
+    // printing for testing. Replace with writing once to a SD memory card.
+    printf("Current time in day month hour.min.sec year is  %s\r\n", ctime(&timeNTP));
+    printf("The time taken was %llu microseconds\n", stopwatch.elapsed_time().count());
+    
+    printf("\nWe stopped sending more UDP packets to the server.\nYou can unplug your device!\n");
+    //ThisThread::sleep_for(2s);
+    }
+}
+
+// The functions
+  
+time_t getNTP() {
+    NTPClient ntp(&net);
+    ntp.set_server(ntpAddress, ntpPort);
+    time_t timestamp = ntp.get_timestamp();
+    if (timestamp < 0) {
+        printf("An error occurred when getting the time. Code: %u\r\n", timestamp);
+    } 
+    else {     // the printings for testing only!
+        //printf("The timestamp seconds from the NTP server in\r\n  32 bit hexadecimal number is %X\r\n", timestamp);
+        //printf("  decimal number is %u\r\n", timestamp);
+        timestamp += (60*60*2);  //  GMT +2  for Finland for the winter time.
+        //printf("Current time is %s\r\n", ctime(&timestamp));
+    } 
+    return timestamp; 
+}
+    
+void udpReceive()
+{
+    int bytes;
+    while(1) {
+        bytes = serverUDP.recvfrom(&clientUDP, &in_data, BUFF_SIZE);
+        printf("\n");
+        printf("bytes received: %d\n",bytes);
+        printf("string: %s\n",in_data);
+        printf("client address: %s\n", clientUDP.get_ip_address());
+        printf("\n");
+        newDatagram = 1;;
+        }
+}
+
+void udpSend()
+{
+        char out_data[BUFF_SIZE];
+        
+        snprintf(out_data, BUFF_SIZE, "UDP message for getting the echo" );
+        clientUDP.set_port(REMOTE_PORT);
+        serverUDP.sendto(clientUDP, out_data, sizeof(out_data));
+        printf("Sending out: %s\n", out_data);
+        printf("with %d" , sizeof(out_data));
+        printf(" data bytes in UDP datagram\n");
+        
+}