ESP8266 Community Forum

- Fri Dec 19, 2014 1:15 pm #5192 Hi,
Attached ntp.lua(.txt) can be used to get the current time from a NTP-Server or to keep a table-structure (hour,minute and second) constantly sync'ed (using a timer-function)

To run the 'realtime-daemon ':

Code: Select allTIME=loadfile("ntp.lua")()
TIME:run(1,10,1800,"193.170.62.252")

will start a timer that:
- uses timer 1
- updates the internal 'clock' every 10 seconds
- and adjusts the clock every 30minutes (using an address from 3.at.pool.ntp.org)
(timeserver - ip can be omitted when 'ntpserver' inside the code is set)
Global TIME.hour TIME.minute and TIME.second will constantly be updated then..
Once started, you can save some memory be setting TIME.run=nil

For a one-time call use:

Code: Select allloadfile("ntp.lua")():sync(function(T) end)

The function passed to :sync() will be called with a table as argument (T.hour T.minute T.second) once the NTP-server answered

Important: the program currently needs an internal timer (configurable in the source) for 'guarding' the udp-call against memory leakage.
Maybe this can be changed by setting up a single 'connect' and 'receive-handler' on startup but i haven't tried yet

To be honest, the 'full daemon' probably eats too much ram to be combined with 'real' work but perhaps you can tailor it to your needs...

Thomas

Attachments

ntp.lua.txt

(2.87 KiB) Downloaded 1973 times

- Sat Dec 20, 2014 6:22 am #5231 This is really annoying. Just discovered that the addition of the 'guard' - timerfunction works well in 'daemon'-mode but actually prevents a one-time - call from freeing it's memory

The problem is that an unanswered udp-query leaks memory permanently as no further event is fired. If the query is answered, I get 'received' and can close the connection and all is well but if not....

Working on a solution but somehow I am getting tired of fighting memory...

Thomas

- Tue Dec 23, 2014 11:59 am #5546 Thomas,
When you set TIME=nil after having it started with TIME:run the initiated timer is not stopped.
This leads to reboot esp8266 after a while, I presume when the garbage collect hits the TIME table.
I tried to find how to add a destructor to the ntp but (as far as I know now) that is not possible to a table in lua.
Only way I can think of now (but I am unexperienced in lua) is as separate call to be made by the "user" which stops the timer.
Or are there other/better solutions ?
Herman

- Thu Jan 01, 2015 4:11 am #6052 Hi!
self.sk:on("receive",function(sck,payload)
-- tmr.stop(self.udptimer)
sck:close() << in this line sk or sck close????
--------
Happy New Year
Puzsar