ntptime.py

import utime
#import machine
from machine import RTC

try:
    import usocket as socket
except:
    import socket
try:
    import ustruct as struct
except:
    import struct



## DETERMINE THE NTP DELTA
## =======================
## (date(2000, 1, 1) - date(1900, 1, 1)).days * 24 * 60 * 60
NTP_DELTA = 3155673600

## SET THE NTP HOST
## ================
## Some reputable hosts:
## - pool.ntp.org
## - 0.us.pool.ntp.org
## - 1.us.pool.ntp.org
## - time.nist.gov
## - time1.google.com
## - time2.google.com
#host = "pool.ntp.org"


#def ntp_print_warning(has_been_warned=False):
#   print("The default time server used with settime() is pool.ntp.org and has no provision for changing it, short of manually editing the text file.")


def print_timeset_msg(time_was_set=True):
    print("--- The time was successfully set via NTP ---")


def getntptime(ntphost):
    NTP_QUERY = bytearray(48)
    NTP_QUERY[0] = 0x1b
    addr = socket.getaddrinfo(host, 123)[0][-1]
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.settimeout(1)
    res = s.sendto(NTP_QUERY, addr)
    msg = s.recv(48)
    s.close()
    val = struct.unpack("!I", msg[40:44])[0]
    return val - NTP_DELTA


## NOTE: There's currently no timezone support in MicroPython!
##       As a workaround, utime.localtime() will return UTC time
##       as if it was a call to .gmtime() instead.

# This call to settime() is hardcoded to use "pool.ntp.org"
def settime(ntpserver="pool.ntp.org"):
#   ntp_print_warning(False)
    t = getntptime(ntpserver)
#   import machine
#   import utime
    tm = utime.localtime(t)
    tm = tm[0:3] + (0,) + tm[3:6] + (0,)
#   machine.RTC().datetime(tm)
    RTC().datetime(tm)
    print_timeset_msg(True)

# This call to settime2 allows specification of the desired NTP server
def settime_advanced(myntphost):
    t = getntptime(myntphost)
#   import machine
#   import utime
    tm = utime.localtime(t)
    tm = tm[0:3] + (0,) + tm[3:6] + (0,)
#   machine.RTC().datetime(tm)
    RTC().datetime(tm)
    print_timeset_msg(True)