ntpclient2.cpp

00001 #include "EthernetNetIf.h"
00002 #include "SimpleSocket.h"
00003 
00004 typedef unsigned long long Time64;
00005 
00006 Time64 toTime64(char buf[]) {
00007     Time64 time64 = 0;
00008     for (int i = 0; i < 8; i++) {
00009         time64 = (time64 << 8) | buf[i];
00010     }
00011     return time64;
00012 }
00013 
00014 Time64 toTime64(int usecs) {
00015     return Time64(double(usecs) * (1ULL << 32) / 1000000);
00016 }
00017 
00018 void printTime64(char *title, Time64 time64) {
00019     unsigned long seconds = (unsigned long) (time64 >> 32);
00020     unsigned long subsecs = (unsigned long) (time64 & 0xFFFFFFFFULL);
00021     char buf[16];
00022 
00023     time_t jstime = time_t(seconds - 2208988800UL) + 9 * 3600;
00024     strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
00025     printf("%s: %s", title, buf);
00026     sprintf(buf, "%f\n", (double) subsecs / (1ULL << 32));
00027     printf("%s", &buf[1]);
00028 }
00029 
00030 void ntpclient2() {
00031     EthernetNetIf eth;
00032     eth.setup();
00033 
00034     char *NTP_SERVER = "pool.ntp.org";
00035     char buf[48] = {0x23};// 00100011 LI(0), Version(4), Mode(3: Client)
00036     Timer timer;
00037     Time64 adjustedTime = 0;
00038 
00039     for (int count = 0; count < 5; count++) {
00040         buf[0] = 0x23;
00041         DatagramSocket datagram;
00042         datagram.write(buf, sizeof(buf));
00043         timer.reset();
00044         datagram.send(NTP_SERVER, 123);
00045         timer.start();
00046         if (datagram.receive() > 0) {
00047             int turnaround = timer.read_us();
00048             if (datagram.read(buf, sizeof(buf))) {
00049                 Time64 receivedTime = toTime64(&buf[32]);
00050                 Time64 transferTime = toTime64(&buf[40]);
00051                 adjustedTime = toTime64(turnaround / 2) + receivedTime / 2 + transferTime / 2;
00052                 timer.reset();
00053                 timer.start();
00054                 printTime64("transfer", transferTime);
00055                 printTime64("adjusted", adjustedTime);
00056                 printf("\n");
00057             }
00058         } else {
00059             wait(5);
00060         }
00061     }
00062 
00063     float subsecs = (double) (adjustedTime & 0xFFFFFFFFULL) / (1ULL << 32);
00064     wait(1 - subsecs);
00065     set_time((size_t) ((adjustedTime >> 32) - 2208988800UL) + 1);
00066 
00067     time_t jstime = time(NULL) + 9 * 3600;
00068     strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
00069     printf("RTC delta = %6d, %s\n\n", timer.read_us(), buf);
00070 
00071     for (int count = 0; count < 20; count++) {
00072         buf[0] = 0x23;
00073         DatagramSocket datagram;
00074         datagram.write(buf, sizeof(buf));
00075         timer.reset();
00076         datagram.send(NTP_SERVER, 123);
00077         timer.start();
00078         if (datagram.receive() > 0) {
00079             int turnaround = timer.read_us();
00080             if (datagram.read(buf, sizeof(buf))) {
00081                 Time64 receivedTime = toTime64(&buf[32]);
00082                 Time64 transferTime = toTime64(&buf[40]);
00083                 adjustedTime = toTime64(turnaround / 2) + receivedTime / 2 + transferTime / 2;  
00084                 printTime64("adjusted", adjustedTime);
00085                 time_t jstime = time(NULL) + 9 * 3600;
00086                 strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
00087                 printf("     RTC: %s\n\n", buf);
00088             }
00089         } else {
00090             wait(5);
00091         }
00092     }
00093 
00094 }