Syncing RTC To Network Time
livius last edited by
what you got when you do?:
I have been looking at the same issue tonight and came up with this script
# imports from machine import Pin import pycom import time 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)[-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) t -= TIME1970 rtc.calibration(t) return t def pin_handler(arg): print("Got an interrupt in pin %s" % (arg.id())) pycom.rgbled(0x0000ff) time.sleep(1) pycom.rgbled(0x000000) print(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)
however the calibration method doesn't like it
>>> Got an interrupt in pin P10 Unhandled exception in interrupt handler Traceback (most recent call last): File "<stdin>", line 36, in pin_handler File "<stdin>", line 28, in getNTPTime OverflowError: overflow converting long int to machine word
@dchappel - to communicate with a ntp server you need the socket.sendto(), however I believe this is not implemented yet.
Also, the rtc interrupts is not implemented yet, so you can't really power down the device int low power mode and wake it up again.
The RTC module is there, but in my opinion it is not yet usable.
In my boot.py after connecting to WiFi, I open up a socket and query the NIST servers, they provide UTC time accurate to the second. You can the parse the string and initialize your RTC from there.
This is all you have to do. However, time will differ, unless you live on the prime meridian.
>>import socket >>s=socket.socket() >>s.connect(socket.getaddrinfo("time.nist.gov",13)[-1]) >>s.recv(1024) >>'\n57777 17-01-24 16:42:49 00 0 0 595.8 UTC(NIST) * \n'
Im using an older firmware that doesn`t include the RTC class, so I have a formula to calculate the epoch time during boot and save it to a variable. This works for most applications as epoch time is more common.
Hope this helps.