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Jesse Jaggars
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making this a git repo
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‎.gitignore‎

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*.sw*

‎NTP.cpp‎

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#include "WProgram.h"
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#include "NTP.h"
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NTP::NTP(byte address[])
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{
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_address[0] = address[0];
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_address[1] = address[1];
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_address[2] = address[2];
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_address[3] = address[3];
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}
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NTP::~NTP()
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{
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}
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unsigned long NTP::get_time()
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{
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call();
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return _send_timestamp;
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}
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int NTP::get_leap_indicator(byte b)
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{
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return b >> 6;
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}
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int NTP::get_version(byte b)
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{
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byte c = b << 2;
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return c >> 5;
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}
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int NTP::get_mode(byte b)
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{
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byte c = b << 5;
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return c >> 5;
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}
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unsigned long NTP::get_ulong()
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{
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unsigned long ulong = (unsigned long)UdpBytewise.read() << 24;
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ulong |= (unsigned long)UdpBytewise.read() << 16;
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ulong |= (unsigned long)UdpBytewise.read() << 8;
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ulong |= (unsigned long)UdpBytewise.read();
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return ulong;
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}
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unsigned long NTP::get_time_discard_precision()
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{
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unsigned long time = get_ulong();
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// we are going to discard the sub-second stuff
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UdpBytewise.read();
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UdpBytewise.read();
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UdpBytewise.read();
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UdpBytewise.read();
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return time;
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}
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void NTP::write_n(int what, int how_many)
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{
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for( int i = 0; i < how_many; i++ )
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UdpBytewise.write(what);
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}
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int NTP::send_ntp_packet()
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{
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UdpBytewise.begin(123);
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UdpBytewise.beginPacket(_address, 123);
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// LI, Version, Mode
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UdpBytewise.write(B11100011);
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// Stratum
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UdpBytewise.write(0);
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// Polling Interval
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UdpBytewise.write(6);
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// Peer Clock Precision
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UdpBytewise.write(0xEC);
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// Root Delay
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write_n(0, 4);
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// Root Dispersion
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write_n(0, 4);
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// Reference Clock Id
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UdpBytewise.write(49);
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UdpBytewise.write(0x4E);
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UdpBytewise.write(49);
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UdpBytewise.write(52);
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// Reference CLock Update Time
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write_n(0, 8);
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// Originate Time Stamp
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write_n(0, 8);
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// Receive Time Stamp
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write_n(0, 8);
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// Transmit Time Stamp
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write_n(0, 8);
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// End
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return UdpBytewise.endPacket();
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}
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void NTP::call()
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{
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send_ntp_packet();
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delay(1000);
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if ( UdpBytewise.available() ) {
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byte first_byte = UdpBytewise.read();
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_leap_indicator = get_leap_indicator(first_byte);
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_version = get_version(first_byte);
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_mode = get_mode(first_byte);
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_stratum = (int)UdpBytewise.read();
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_polling_interval = 1 << ((int)UdpBytewise.read());
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_precision = (char)UdpBytewise.read();
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_delay_interval = (float) get_ulong();
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_dispersion = (float) get_ulong();
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_ref_clock_id[0] = UdpBytewise.read();
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_ref_clock_id[1] = UdpBytewise.read();
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_ref_clock_id[2] = UdpBytewise.read();
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_ref_clock_id[3] = UdpBytewise.read();
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_ref_clock_update_time = get_time_discard_precision();
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_orig_timestamp = get_time_discard_precision();
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_recv_timestamp = get_time_discard_precision();
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_send_timestamp = get_time_discard_precision();
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}
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}

‎NTP.h‎

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#ifndef NTP_h
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#define NTP_h
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#include "WProgram.h"
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#include <UdpBytewise.h>
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class NTP
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{
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public:
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NTP(byte address[]);
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~NTP();
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unsigned long get_time();
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private:
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byte _address[4];
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int _leap_indicator;
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int _version;
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int _mode;
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int _stratum;
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int _polling_interval;
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int _precision;
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float _delay_interval;
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float _dispersion;
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byte _ref_clock_id[4];
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unsigned long _ref_clock_update_time;
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unsigned long _orig_timestamp;
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unsigned long _recv_timestamp;
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unsigned long _send_timestamp;
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int send_ntp_packet();
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unsigned long get_ulong();
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unsigned long get_time_discard_precision();
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void write_n(int what, int how_many);
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int get_leap_indicator(byte b);
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int get_version(byte b);
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int get_mode(byte b);
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void call();
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};
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#endif

‎README‎

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This library makes it easy to fetch a timestamp from an NTP timeserver. In order to use this library you will need the UDP libraries from:
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http://bitbucket.org/bjoern/arduino_osc/
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You will also need to modify the library to allow enough space in the buffers for the NTP packets. Open up UdpBytewise.h and change these lines:
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#define UDP_TX_PACKET_MAX_SIZE 32
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#define UDP_RX_PACKET_MAX_SIZE 32
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to this:
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#define UDP_TX_PACKET_MAX_SIZE 64
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#define UDP_RX_PACKET_MAX_SIZE 64

‎examples/ntp.pde‎

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#include <Ethernet.h>
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#include <NTP.h>
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byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //MAC address to use
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byte ip[] = { 192, 168, 1, 44 }; // Arduino's IP address
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byte gw[] = { 192, 168, 1, 1 }; // Gateway IP address
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byte time_dot_nist_dot_gov[] = { 192, 43, 244, 18}; //time.nist.gov
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void setup()
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{
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Serial.begin(9600);
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Ethernet.begin(mac,ip,gw);
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NTP ntp(time_dot_nist_dot_gov);
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unsigned long time = ntp.get_time();
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Serial.println(time);
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}
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void loop()
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{
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}
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‎keywords.txt‎

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#######################################
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# Syntax Coloring Map For NTP
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#######################################
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#######################################
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# Datatypes (KEYWORD1)
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#######################################
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NTP KEYWORD1
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#######################################
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# Methods and Functions (KEYWORD2)
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#######################################
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#######################################
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# Constants (LITERAL1)
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#######################################

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