Syncing RTC To Network Time



  • Documentation states:

    "The current calendar time may be set using machine.RTC().datetime(tuple) function, and maintained by following means:

    • By a backup battery (which may be an additional, optional component for a particular board).

    • Using networked time protocol (requires setup by a port/user).

    • Set manually by a user on each power-up (many boards then maintain RTC time across hard resets, though some may require setting it again in such case)."

    Does anyone have a simple way they have come up with to sync the RTC to an open network source (bullet 2 above)?



  • @rdixey Ok, it seems interesting. Will try!

    Thanks



  • @rdixey said in Syncing RTC To Network Time:

    instructions

    Without explanation that function is twice in doc - this was my first hint ;-)



  • @livius Excuse Me :) I already know what mktime() is. And I don't need anyone to give me instructions on using google to find info. I was pointing out a typo in the doc's.

    https://docs.pycom.io/pycom_esp32/library/utime.html

    mktime is the first function in the list and is described as 'Convert a time expressed in seconds since the Epoch.' I believe this is an error and should be gmtime().

    mktime is listed again as the third functon and described correctly.

    gmtime() is not in the list at all.



  • @santorcuato I used it as a function in the boot.py of my LoPy. I had to set a delay to allow for the round trip to pool.ntp.org or else the function completed before ntp_sync and RTC remained = Unix Epoch . When I ping pool.ntp.org from my LAN the longest round trip was 630ms so I set sleep at 750ms. Less than that was too short.

    def setRTCLocalTime():
        rtc = machine.RTC()
        rtc.ntp_sync("pool.ntp.org")
        utime.sleep_ms(750)
        print('\nRTC Set from NTP to UTC:', rtc.now())
        utime.timezone(-18000)
        print('Adjusted from UTC to EST timezone', utime.localtime(), '\n')
    
    Connecting to a LoPy...
    Connected
    >>> 
    PYB: soft reboot
    
    RTC Set from NTP to UTC: (2017, 2, 26, 13, 18, 54, 225113, None)
    Adjusted from UTC to EST timezone (2017, 2, 26, 8, 18, 54, 6, 57)
    


  • @rdixey said in Syncing RTC To Network Time:

    @abilio These new rtc.ntp_sync() & time.timezone() functions work nicely with the 1.6.4.b1 update. They are very convenient!

    I think there is a typo on the Utime doc page though. The first function listed there is utime.mktime([secs]), is this intended to be utime.gmtime()?

    Thanks for the good work on this :)

    Its not working for me :-(

    Can you post a working example?

    Thanks!



  • @rdixey said in Syncing RTC To Network Time:

    mktime

    It is standard in many languages - google for it ;-)



  • @abilio These new rtc.ntp_sync() & time.timezone() functions work nicely with the 1.6.4.b1 update. They are very convenient!

    I think there is a typo on the Utime doc page though. The first function listed there is utime.mktime([secs]), is this intended to be utime.gmtime()?

    Thanks for the good work on this :)



  • @rdixey, you are totally right and I must personally apologize for it. We forgot to merge it with master just to realize it after making the release (yeah, it happened twice :( ) . I will work so is included in the next firmware release.



  • @abilio Apparently this is not yet implemented in 1.6.1.b1 ?

    '1.6.1.b1'
    >>> os.uname()
    (sysname='LoPy', nodename='LoPy', release='1.6.1.b1', version='v1.8.6-450-g31ef5170 on 2017-02-15', machine='LoPy with ESP32', lorawan='1.0.0')
    >>> import machine
    >>> rtc = machine.RTC()
    >>> rtc.ntp_sync("pool.ntp.org")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    AttributeError: 'RTC' object has no attribute 'ntp_sync'
    >>> 
    >>> import time
    >>> time.timezone(3600)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    AttributeError: 'module' object has no attribute 'timezone'
    


  • @abilio Great, amazing feature.



  • @Knoahlr, to UTC, but then you'll be able to set the time offset calling:

    time.timezone(3600) # GMT +1 for the Netherlands
    

    A call to time.localtime() will return the time using the provided offset. If you want the number of seconds since Epoch adjusted to the timezone, you can do something like:

    time.time() + time.timezone()
    

    Also, time.gmtime() will be included, working like time.localtime(), but without adjusting for the offset.

    So far, this is what would be available in the release.



  • @abilio Will the method sync the RTC to local time or UTC ?



  • @abilio that's great news and much easier to use. Cheers for the good work!



  • We've just finished adding support for a NTP (SNTP) client. Syncing time will be as easy as:

    import machine
    rtc = machine.RTC()
    rtc.ntp_sync("pool.ntp.org") # select an appropriate server
    

    By default it will resync every hour, but you can change the period by passing it as a parameter: rtc.ntp_sync("pool.ntp.org", 1200) # do it every 20 minutes

    This feature will probably be included in the next release. Hope you'll find it useful.



  • Ok I got it. I have to use utime for localtime method to work with the large int else you get an error.

    from machine import Pin
    import pycom
    import utime
    import ustruct
    from machine import RTC
    import socket
    from socket import AF_INET, SOCK_DGRAM
    
    pycom.heartbeat(False)
    
    rtc = RTC()
    rtc.init((1970, 0, 0, 0, 0, 0, 0, 0))
    
    def getNTPTime(host = "pool.ntp.org"):
        port = 123
        buf = 1024
        address = socket.getaddrinfo(host,  port)[0][-1]
        msg = '\x1b' + 47 * '\0'
        msg = msg.encode()
        TIME1970 = 2208988800 # 1970-01-01 00:00:00
    
        # connect to server
        client = socket.socket(AF_INET, SOCK_DGRAM)
        client.sendto(msg, address)
        msg, address = client.recvfrom(buf)
        t = ustruct.unpack("!12I", msg)[10]
        t -= TIME1970
        tuple_time = utime.localtime(t)
        rtc.init((tuple_time))
        client.close()
    
    
    def pin_handler(arg):
        print("Got an interrupt in pin %s" % (arg.id()))
        pycom.rgbled(0x0000ff)
        utime.sleep(1)
        pycom.rgbled(0x000000)
        getNTPTime()
        print(rtc.now())
    
    # use the button on the expansion board  P10
    p_in = Pin('G17',  mode=Pin.IN,  pull=Pin.PULL_UP)
    # on button push trigger pin_handler
    p_in.callback(Pin.IRQ_FALLING,  pin_handler)


  • @dchappel You might want to use RegEX,
    Assuming Current time is your response from the NIST server.

    >>import re
    >>CurrentTime='\n57783 17-01-30 16:14:50 00 0 0  37.8 UTC(NIST) * \n'
    >>DateList=re.search("[0-9]+-[0-9]+-[0-9]+",CurrentTime).group(0).split("-")
    >>DateList
    ['17', '01', '30']
    >>TimeList=re.search("[0-9]+:[0-9]+:([0-9]+.[0-9]+)",CurrentTime).group(0).split(":")
    >>TimeList
    ['16', '14', '50 00']
    

    Cheers.



  • Here is what I came up with (builds on Knoahlr contribution below):

    import socket
    import machine
    
    s=socket.socket()
    s.connect(socket.getaddrinfo("66.199.22.67",13)[0][-1])
    r=s.recv(1024).decode()
    s.close()
    
    year = 2000 + int(r[6:9])
    month = int(r[10:12])
    day = int(r[13:15])
    hour = int(r[16:18])
    min = int(r[19:21])
    sec = int(r[22:24])
    rtc = machine.RTC()
    rtc.init((year, month, day, hour, min, sec, 0, 0))
    print(rtc.now())
    

    Current time (in seconds since 1970 / UNIX time) is now available using utime.time().

    I found that I needed to use the numeric IP address for NIST. Alpha URL gave me a timeout. Since I got it to work with numeric I didn't go back and try to understand why...



  • @thefebruaryman
    ok - then you succesfully got value
    but issue is in calibration procedure
    but i suppose you can fix problem by setting time by

    ct = time.ctime(t)
    rtc.init((ct[0], ct[1], ct[2], ct[3], ct[4], ct[5], 0, 0))
    


  • t = ustruct.unpack("!12I", msg)[10]
    

    returns

    1485764691
    

    which in python I can normally

    >>> time.ctime(1485764691)
    'Mon Jan 30 08:24:51 2017'

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