ntp_notes

import socket
import ustruct as struct
NTP_DELTA = 315567360
NTP_QUERY = bytearray(48)
NTP_QUERY[0] = 0x1b
host = "192.168.1.126"
addr = socket.getaddrinfo(host, 123)[0][-1]
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.settimeout(1)


t0 = utime.time()
res = s.sendto(NTP_QUERY, addr)
msg = s.recv(48)
s.close()
t3 = utime.time()


val = struct.unpack("!I", msg[40:44])[0]
t1 = val - 3155673600
val = struct.unpack("!I", msg[32:36])[0]
t2 = val - 3155673600
(t1 - t0) + (t2 - t3) /2
tm = utime.localtime(t1)
tm = tm[0:3] + (0,) + tm[3:6] + (0,)

machine.RTC().datetime(tm)

utime.localtime()



t = val - NTP_DELTA

import machine
import utime
tm = utime.localtime(t)


curl -s https://updates.signal.org/desktop/apt/keys.asc | sudo apt-key add -
echo "deb [arch=amd64] https://updates.signal.org/desktop/apt xenial main" | sudo tee -a /etc/apt/sources.list.d/signal-xenial.list
sudo apt update && sudo apt install signal-desktop