Question

我正在尝试联系使用WiFiShield发送UDP数据包的NTP服务器来同步我的Arduino Uno上的时间。我花了几个小时阅读不同的教程和论坛但没有成功。无论我的代码是什么，http://arduino.cc/en/Tutorial/UdpNTPClient的示例都不起作用。我没有回应。在使用wireshark后，我甚至不确定Arduino是否发送了数据包。

我尝试了什么：

将Arduino IDE 1.0.3与IDE 1.0.5的WiFi库一起使用（因为1.0.3中不存在WiFiUdp）或使用Arduino IDE 1.0.5
使用IDE 1.0.5附带的固件升级WiFiShield的固件。但是，我无法检查它是否成功或之前安装了什么固件版本。
SimpleWebServerWiFi等其他示例正在运作。
在我的笔记本电脑上使用相同的WiFi设置ntp服务器并联系该服务器。
更改目标服务器，检查http://tf.nist.gov/tf-cgi/servers.cgi的可用性
使用wireshark（本地服务器）或wireshark +本地arp欺骗检查Arduino发送/接收的数据包，以通过wireshark（公共服务器）路由流量，但在任何情况下我都无法检测到任何数据包。
检查definition of the NTP但数据包创建看起来不错。
增加响应的等待时间。

为了让你冷静下来我改变了代码，不是每10秒请求一次，但它似乎还没有发送请求...

任何提示？

来自http://arduino.cc/en/Tutorial/UdpNTPClient的代码：

/*

 Udp NTP Client

 Get the time from a Network Time Protocol (NTP) time server
 Demonstrates use of UDP sendPacket and ReceivePacket
 For more on NTP time servers and the messages needed to communicate with them,
 see http://en.wikipedia.org/wiki/Network_Time_Protocol

 created 4 Sep 2010
 by Michael Margolis
 modified 9 Apr 2012
 by Tom Igoe

 This code is in the public domain.

 */

#include <SPI.h>        
#include <WiFi.h>
#include <WiFiUdp.h>

int status = WL_IDLE_STATUS;
char ssid[] = "mynetwork";  //  your network SSID (name)
char pass[] = "mypassword";       // your network password
int keyIndex = 0;            // your network key Index number (needed only for WEP)

unsigned int localPort = 2390;      // local port to listen for UDP packets

IPAddress timeServer(129, 6, 15, 28); // time.nist.gov NTP server

const int NTP_PACKET_SIZE = 48; // NTP time stamp is in the first 48 bytes of the message

byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets

// A UDP instance to let us send and receive packets over UDP
WiFiUDP Udp;

void setup()
{
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    // don't continue:
    while(true);
  }


  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:    
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(10000);
  }

  Serial.println("Connected to wifi");
  printWifiStatus();

  Serial.println("\nStarting connection to server...");
  Udp.begin(localPort);
}

void loop()
{
  sendNTPpacket(timeServer); // send an NTP packet to a time server
    // wait to see if a reply is available
  delay(1000);  
  Serial.println( Udp.parsePacket() );
  if ( Udp.parsePacket() ) {
    Serial.println("packet received");
    // We've received a packet, read the data from it
    Udp.read(packetBuffer,NTP_PACKET_SIZE);  // read the packet into the buffer

    //the timestamp starts at byte 40 of the received packet and is four bytes,
    // or two words, long. First, esxtract the two words:

    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
    unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);  
    // combine the four bytes (two words) into a long integer
    // this is NTP time (seconds since Jan 1 1900):
    unsigned long secsSince1900 = highWord << 16 | lowWord;  
    Serial.print("Seconds since Jan 1 1900 = " );
    Serial.println(secsSince1900);              

    // now convert NTP time into everyday time:
    Serial.print("Unix time = ");
    // Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
    const unsigned long seventyYears = 2208988800UL;    
    // subtract seventy years:
    unsigned long epoch = secsSince1900 - seventyYears;  
    // print Unix time:
    Serial.println(epoch);                              


    // print the hour, minute and second:
    Serial.print("The UTC time is ");       // UTC is the time at Greenwich Meridian (GMT)
    Serial.print((epoch  % 86400L) / 3600); // print the hour (86400 equals secs per day)
    Serial.print(':');  
    if ( ((epoch % 3600) / 60) < 10 ) {
      // In the first 10 minutes of each hour, we'll want a leading '0'
      Serial.print('0');
    }
    Serial.print((epoch  % 3600) / 60); // print the minute (3600 equals secs per minute)
    Serial.print(':');
    if ( (epoch % 60) < 10 ) {
      // In the first 10 seconds of each minute, we'll want a leading '0'
      Serial.print('0');
    }
    Serial.println(epoch %60); // print the second
  }
  // wait ten seconds before asking for the time again
  delay(10000);
}

// send an NTP request to the time server at the given address
unsigned long sendNTPpacket(IPAddress& address)
{
  //Serial.println("1");
  // set all bytes in the buffer to 0
  memset(packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  // (see URL above for details on the packets)
  //Serial.println("2");
  packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  packetBuffer[1] = 0;     // Stratum, or type of clock
  packetBuffer[2] = 6;     // Polling Interval
  packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  packetBuffer[12]  = 49;
  packetBuffer[13]  = 0x4E;
  packetBuffer[14]  = 49;
  packetBuffer[15]  = 52;

  //Serial.println("3");

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:         
  Udp.beginPacket(address, 123); //NTP requests are to port 123
  //Serial.println("4");
  Udp.write(packetBuffer,NTP_PACKET_SIZE);
  //Serial.println("5");
  Udp.endPacket();
  //Serial.println("6");
}


void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
}

Answer 1

尝试

memset(packetBuffer, 0, NTP_PACKET_SIZE);
packetBuffer[0] = 0b00011011; //  (0x1B) for NTPv3 
// or
// packetBuffer[0] = 0b00100011;` (0x23) for NTPv4

并且不要修改请求结构的其余部分。 NTP将通过此最低要求设置响应客户。

修改：

localPort = 2390这应该是＆＃34; ntp-port＆＃34; （123）？要么即使是8888，如下所述：＆＃34; Network Time Protocol (NTP) Client＆＃34;。 注意：链接看起来与你的链接非常相似，但它不一样。端口的指定方式不同。

代码是否超出setup()。

...
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
  Serial.println("WiFi shield not present");
  // don't continue:
  while(true);
}
...

对我来说很奇怪。＆＃34;不要继续＆＃34;实施繁忙＆＃34;留在这里＆＃34;。

WiFiShield发送NTP请求数据包但没有响应

1 个答案: