Diff: examples/ntpclient2.cpp

Revision:

40:84182fc63956

Parent:

39:108499af2b53

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/ntpclient2.cpp	Mon Feb 04 09:04:25 2013 +0000
@@ -0,0 +1,94 @@
+#include "EthernetNetIf.h"
+#include "SimpleSocket.h"
+
+typedef unsigned long long Time64;
+
+Time64 toTime64(char buf[]) {
+    Time64 time64 = 0;
+    for (int i = 0; i < 8; i++) {
+        time64 = (time64 << 8) | buf[i];
+    }
+    return time64;
+}
+
+Time64 toTime64(int usecs) {
+    return Time64(double(usecs) * (1ULL << 32) / 1000000);
+}
+
+void printTime64(char *title, Time64 time64) {
+    unsigned long seconds = (unsigned long) (time64 >> 32);
+    unsigned long subsecs = (unsigned long) (time64 & 0xFFFFFFFFULL);
+    char buf[16];
+
+    time_t jstime = time_t(seconds - 2208988800UL) + 9 * 3600;
+    strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
+    printf("%s: %s", title, buf);
+    sprintf(buf, "%f\n", (double) subsecs / (1ULL << 32));
+    printf("%s", &buf[1]);
+}
+
+void ntpclient2() {
+    EthernetNetIf eth;
+    eth.setup();
+
+    char *NTP_SERVER = "pool.ntp.org";
+    char buf[48] = {0x23};// 00100011 LI(0), Version(4), Mode(3: Client)
+    Timer timer;
+    Time64 adjustedTime = 0;
+
+    for (int count = 0; count < 5; count++) {
+        buf[0] = 0x23;
+        DatagramSocket datagram;
+        datagram.write(buf, sizeof(buf));
+        timer.reset();
+        datagram.send(NTP_SERVER, 123);
+        timer.start();
+        if (datagram.receive() > 0) {
+            int turnaround = timer.read_us();
+            if (datagram.read(buf, sizeof(buf))) {
+                Time64 receivedTime = toTime64(&buf[32]);
+                Time64 transferTime = toTime64(&buf[40]);
+                adjustedTime = toTime64(turnaround / 2) + receivedTime / 2 + transferTime / 2;
+                timer.reset();
+                timer.start();
+                printTime64("transfer", transferTime);
+                printTime64("adjusted", adjustedTime);
+                printf("\n");
+            }
+        } else {
+            wait(5);
+        }
+    }
+
+    float subsecs = (double) (adjustedTime & 0xFFFFFFFFULL) / (1ULL << 32);
+    wait(1 - subsecs);
+    set_time((size_t) ((adjustedTime >> 32) - 2208988800UL) + 1);
+
+    time_t jstime = time(NULL) + 9 * 3600;
+    strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
+    printf("RTC delta = %6d, %s\n\n", timer.read_us(), buf);
+
+    for (int count = 0; count < 20; count++) {
+        buf[0] = 0x23;
+        DatagramSocket datagram;
+        datagram.write(buf, sizeof(buf));
+        timer.reset();
+        datagram.send(NTP_SERVER, 123);
+        timer.start();
+        if (datagram.receive() > 0) {
+            int turnaround = timer.read_us();
+            if (datagram.read(buf, sizeof(buf))) {
+                Time64 receivedTime = toTime64(&buf[32]);
+                Time64 transferTime = toTime64(&buf[40]);
+                adjustedTime = toTime64(turnaround / 2) + receivedTime / 2 + transferTime / 2;  
+                printTime64("adjusted", adjustedTime);
+                time_t jstime = time(NULL) + 9 * 3600;
+                strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
+                printf("     RTC: %s\n\n", buf);
+            }
+        } else {
+            wait(5);
+        }
+    }
+
+}
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