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

[flotulopex]

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?

[timc]

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

[Charles Linquis]

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.

[gadelhas]

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

[Charles Linquis]

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.

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

[dhouston]

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).