NTP server / External (no "www") time base for PC / DCF77


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  1. #1
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    Default NTP server / External (no "www") time base for PC / DCF77

    Hi there,

    I have built a DCF77 receiver (http://www.ptb.de/en/org/4/44/442/dcf77_1_e.htm) I'd like to use as a time base server in a "private" LAN (= no connection to www).

    As my programming skills are modest, I don't know how to create a NTP software. All I could reach, is a simple DELPHI based tool that will update the PC's internal clock via TIME and DATE DOS commands. I grab the receiver's data via the COM port.

    I had a look at this kind of module http://www.connectone.com/products.asp?did=73&pid=93 that might be of any help. But what about the sofware?
    Roger

  2. #2
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    Default

    NTP on port 123 is going to be a LOT to work on. If you have needs for VERY high accuracy it's what you use. Commercial NTP time servers are in the $2K range See:
    http://www.ntp.org/
    SNTP is easier to deal with (this is what your PC uses to sync up)
    http://www.micro-examples.com/public...nal-clock.html (the code for this is over 1K lines)
    Time Server on port 37 is easier
    http://www.codeproject.com/KB/IP/udptime.aspx
    DayTime server on port 13 is even simpler

    I would start your efforts programming a Time Server client using a PIC ENC28J60. Once you get a little background and practice start working on the server.

    As far a I know no big company ever made a 60/77khz NTP server. There is too much phase shift every day. Most people use GPS as a source for an NTP server. However a 77Khz time source would make a good backup.

    I expect to work on such a project down the road but I will probably use something with a little more power like an Ethernut http://www.ethernut.de/en/index.html They have an example of a SNTP client that is less than 200 lines but written in C code.

    Regards
    Tim

  3. #3
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    I wrote a routine that 'calls' a timeserver on port 123 (UDP protocol). It uses a Lantronix XPort as the network interface.

    The routine calculates current time based on NET TIME (number of seconds elapsed since 00:00:00,Jan 1, 1900). It allows input of time zone and DST flag. It doesn't automatically calculate when DST begins/ends, but it does take DST into account. Leap years, too.

    It shows the current time and then writes the values into a DS1307.

    If someone is interested, I'll post.
    Charles Linquist

  4. #4
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    Quote Originally Posted by Charles Linquis View Post
    I wrote a routine that 'calls' a timeserver on port 123 (UDP protocol). It uses a Lantronix XPort as the network interface.

    The routine calculates current time based on NET TIME (number of seconds elapsed since 00:00:00,Jan 1, 1900). It allows input of time zone and DST flag. It doesn't automatically calculate when DST begins/ends, but it does take DST into account. Leap years, too.

    It shows the current time and then writes the values into a DS1307.

    If someone is interested, I'll post.
    Hi, i'm interested in your project. Can you post the code, please?

    Thanks
    Thanks and Regards;
    Gadelhas

  5. #5
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    It might take a bit of explanation, but -

    The code below is sent after the XPort is initialized for UDP.

    Hoffset is number of hours before or after GMT.
    SIGN is earlier ("1") or later ("2") than GMT.
    The code works only with 18F chips because it uses PBPL.




    Code:
    GETNETTIME:
           
           
           
           NETRETRYCOUNT = 0
           GOSUB INTDISABLE
           
    GETNETTIME2:
          
           HSEROUT [13,10,"TIMESERVER ",#TSIP1,".",#TSIP2,".",#TSIP3,".",#TSIP4,13,10]
           PAUSE 100
         
            THEADER[0] = $2           ' STX
            THEADER[1] = TSIP1  ' DESTINATION IP
            THEADER[2] = TSIP2
            THEADER[3] = TSIP3
            THEADER[4] = TSIP4
    
    
            THEADER[5] = 0            ; DESTINATION PORT HIGHBYTE
            THEADER[6] = 123          ; DESTINATION PORT LOWBYTE
                        
            LRC1 = 0
            LRC2 = 0 
          
            For X = 1 to 6
                 LRC1 = LRC1 ^ THeader[x]
            next X
                           
            THEADER[7] = LRC1               
            THEADER[8] = 0               
            THEADER[9] = 48                                             'Data Length lowbyte
        
    ;Send the header
              HSEROUT [13,10]     
              For X = 0 to 9
                HSEROUT2 [THeader[X]]
              Next X   
             
              LRC2 = LRC2 ^ THeader[8]
              LRC2 = LRC2 ^ THeader[9]
            
    ;Send the data
              HSEROUT2 [$1B]
               LRC2 = LRC2 ^ $1B
              For X = 0 To 46
                HSEROUT2 [0]
                LRC2 = LRC2 ^ 0
              NEXT X     
                      
    ;Send the Checksum (LRC)            
             
              HSEROUT2 [LRC2]
    
    getresponse:         
              
        
             HSERIN2 1000,NoResponse,[Wait($2)]                                                      
             hserin2 200,NoResponse,[SKIP 41,TimeNow.Byte3,TimeNow.Byte2,TimeNow.Byte1,TimeNow.Byte0]
              
                    
             
    '             TIME1900_2009 = 3439756800
    
              READ 851,HOFFSET
                  
                   IF sign = "1" then
                      if DST = 1 and HOffset = 0 THEN 
                           Sign = "2"
                           GOTO OtherSide
                      ENDIF     
                         TimeNow = Timenow - ((HOffset - DST) * 3600)
                   ENDIF
                 
    OtherSide:             
                   IF Sign = "2" THEN
                      TimeNow = TimeNow + ((Hoffset + DST) * 3600)
                   ENDIF   
                                         
                    SINCEJAN2009 = TIMENOW - 3439756800   ; 3439756800 is the #of sec from Jan1 1900 to Jan1 2009
                   
                    RUNNINGSECONDS = SINCEjAN2009
    
                    YR = 2009
                    
    GETYEAR:
            
                        LEAP = (YR//4)    ; = 0 if leap year
                        
                        if LEAP = 0 then
                            SecondsInYear = 31622400 ;366*60*60**24
                         
                        ELSE
                            SecondsInYear = 31536000 ;365*60*60*24
                         
                        endif
                           
                        If RunningSeconds > SecondsInYear Then
                            RunningSeconds = RunningSeconds - SecondsInyear
                            YR = YR + 1
                            GOTO GetYear
                        ENDIF
                   
                     Mo = 1 ; Start with Month = 1  
                            
            
    GETMONTH:        
                    IF LEAP > 0 THEN
                       lookup2 MO,[0,2678400,2419200,2678400,2592000,2678400,2592000,2678400,2678400,2592000,2678400,2592000,2678400],SecondsInMonth
                    ELSE
                       LOOKUP2 MO,[0,2678400,2505600,2678400,2592000,2678400,2592000,2678400,2678400,2592000,2678400,2592000,2678400],SecondsInMonth
                    ENDIF
                    
    
                    If RunningSeconds >= SecondsInMonth THEN
                       RunningSeconds = RunningSeconds - SecondsInMonth
                    
                    MO = MO + 1
                    GOTO GETMONTH
                    ENDIF   
    
    FINDDAYS:
            
                    DA = RUNNINGSECONDS/86400
                    RUNNINGSECONDS = RUNNINGSECONDS//86400
         
                    HR = RUNNINGSECONDS/3600 
                    RUNNINGSECONDS = RUNNINGSECONDS//3600
           
                    MN = RUNNINGSECONDS/60
                    RUNNINGSECONDS = RUNNINGSECONDS//60
    
                    SC = RUNNINGSECONDS
                
                    Da = Da + 1   ; Because there is no day zero
    
                   HSEROUT [13,10,13,10,DEC2 HR,":",DEC2 MN,":",DEC2 SC,"   ",DEC2 MO,"/",DEC2 DA,"/",#YR,13,10] 
    
                   YR8 = YR - 2000 ; clock only takes two digits! 
                    
    ConverttoBCD:             
                   DT = (DA/10) << 4 + (DA//10)
                   YR8 = (YR8/10) << 4 + (YR8//10)
                   MN = (MN/10) << 4 + (MN//10)
                   SC = (SC/10) << 4 + (SC//10)
                   HR = (HR/10) << 4 + (HR//10)
                   MO = (MO/10) << 4 + (MO//10)
                   gosub CLOCKWRITE
                   NetFail = 0
                   HSEROUT ["CLK updated",13,10]
                    pause 2000
                  goto DoneClock
              
                     
    NoResponse: 
                   hserout ["RETRYING GetNetTime",13,10]
                     pause 1000
                     
                     NETRETRYCOUNT = NETRETRYCOUNT + 1 
                     
                     if NETRETRYCOUNT < 5 THEN 
                        goto getnettime2
                     ENDIF
                     IF NETRETRYCOUNT < 10 THEN
                        GOSUB GETALTERNATESERVER
                        goto getnettime2
                     ENDIF
                     
                        READ 800,Dummy
                        TSIP1 = Dummy
                        THEADER[1] = TSIP1  'Set it back to primary
                        READ 801,Dummy
                        TSIP2 = Dummy
                        THEADER[2] = TSIP2
                        READ 802,Dummy
                        TSIP3 = Dummy
                        THEADER[3] = TSIP3
                        READ 803,Dummy
                        TSIP4 = Dummy
                        THEADER[4] = TSIP4
                        NetFail = 1
                     HSEROUT [13,10,"FAILED NET TIME",13,10]
         
    DoneClock:                 
             
             GOSUB INTREENABLE  
             
             RETURN
    Charles Linquist

  6. #6
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    Thumbs up

    Thanks, Charles. I've been planning to write a similar procedure although I 'm using a different ethernet adapter (WIZ110SR), different RTC (ST M41T81) and different processor (ZBasic ZX40p). Still, adapting your code should save me a lot of time and error.

    BTW, I've also used the ConnectOne nano LanReach mentioned by the OP. It has a very attractive price, easy communication protocol (patterned after modem AT commands) and a nice set of Internet protocols (e.g. SMTP/POP3 for email which are much easier to use than Lantronix). Unfortunately, Mouser will not ship it outside the USA due to Homeland Security issues.

    Also, Tibbo (http://tibbo.com/products/) has several ethernet-serial adapters some of which can be programmed in their Basic dialect. They have source examples for email, SNTP, etc. on their website. Unfortunately, their XPort like versions are not sold in the USA (I suspect because of Lantronix patents).
    Last edited by dhouston; - 30th October 2010 at 13:21.

  7. #7
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    I started using Lantronix years ago, because I bought their development kit first and also because of the small size of the XPort. I built up this complex scheme of writing the setup records over the serial port (since the customer dictated that setup NOT be allowed over Ethernet). The first board (18F8720 + XPort) started out as telnet only, but I just kept adding capability. First UDP then SNMP. The SNMP part was the hardest, because - while the most devices claim to support SNMP, they mean that the device itself terminates the SNMP request. That doesn't work for me, because I needed to support SNMP reading *MY* sensors. So the XPort has to become a UDP tunnel and I have to process the SNMP packets and OIDs in my code - not trivial! I also must send SNMP traps upon errors.

    Later on, I needed SNMP and SSH/SSL simultaneously, so I used the Lantronix MatchPort AR. It handles the encryption. But setting up that device is not easy either - it uses XML records!

    The biggest challenge was finding devices that allowed relatively easy configuration and setup over the SERIAL port, and yet blocked all attempts to configure through Ethernet (and would't even respond to pings). Military protocols demand that. All the serial<->Lan people want to impress me with the easy setup over Ethernet using a GUI. I tell them that is the exact opposite of what I need!

    Like so many other cases - I'm so far down the road with Lantronix, it would be hard to switch now.
    Charles Linquist

  8. #8
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    Quote Originally Posted by Charles Linquis View Post
    Like so many other cases - I'm so far down the road with Lantronix, it would be hard to switch now.
    Understood. I wasn't trying to convert you, anyway. But, for people just starting with this, looking at WizNET (http://www.wiznet.co.kr/en/), ConnectOne (http://www.connectone.com/default.asp) and Tibbo (http://tibbo.com/) is a good idea if only to get an idea of the various choices available.

    PS: I also used the XPort but it was my second route. My first was with BasCom AVR.

  9. #9
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    Thank you Charles!
    Thanks and Regards;
    Gadelhas

  10. #10
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    Default Re: NTP server / External (no "www") time base for PC / DCF77

    Charles,

    Thanks for your code post. I was considering a Netburner 'PINK' module, but you've got me looking at the Lantronix Pro again. I have to admit that I'm really in the dark when doing an ethernet project!! If I'm primarily interested in sending emails and (in the future) acquiring the time, and serving up a simple web page to give input to a PIC project, what Lantronix evaluation board should I buy? I'm equally unexperienced in Linux and 'Evolution' OS's, but need to buy an eval board just to have a ready-built platform in which to experiment sending and receiving serially from my PIC to the Lantronix. With really NO experience, except for PIC's and PBP, which eval board from Lantronix would you buy?

    Thanks for your opinion, and best regards,
    Len G.

  11. #11
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    Default Re: NTP server / External (no "www") time base for PC / DCF77

    I've decided to give Lantronix Matchport module a try. Onward.

  12. #12
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    Default Re: NTP server / External (no "www") time base for PC / DCF77

    IIRC, Roving Network's RN-XV http://www.rovingnetworks.com/products/RN_XV WiFly module automatically contacts an NTP server and updates its onboard RTC every 4 hours. It's also quite inexpensive ($35) and connects via serial.
    Last edited by dhouston; - 21st July 2012 at 20:49.

  13. #13
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    Default Re: NTP server / External (no "www") time base for PC / DCF77

    My memory is a bit cloudy. (I've been in/out of hospital 7 times in past 3 months which wreaks havoc on continuity.) You supply the RN-XV an IP for a SNTP server and it can be configured to get the time at power-up and every 0-??? minutes afterwards.

    See the User Manual which you can d/l from http://www.rovingnetworks.com/resources/show/product:1

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