Problem with setTimeout() and deep sleep mode #4687

espruino-discuss3 · 2025-02-12T13:11:25Z

espruino-discuss3
Feb 12, 2025
Maintainer

Posted at 2015-02-10 by net-tobi

Hello everyone,

I am using the current release of Espruino together with the Espruino Board v1.4b and I experienced a weird problem with setTimeout() and deep sleep by using the following peace of code:

function perform() {
    blink(5000, function() {
        setTimeout(function() {
            perform();
        }, 3600 * 1000);
        setDeepSleep(1);
    });
};
var blink = function(t, callback) {
    var on = false;
    var i = setInterval(function() { 
        on = !on;
        digitalWrite(LED2, on);
    }, 500);
    setTimeout(function() { 
        digitalWrite(LED2, false);
        clearInterval(i);
        callback();
    }, t);
};
perform();

This code shall let the device blink for 5sec every hour and go into deep sleep mode after blinking. This works for a while and then it suddenly stops blinking without any error being raised or the light is blinking faster with very low power.

The batteries are fully charged. This behaviour can not be reproduced when the device is connected via USB.

Do you have an idea?

Best,

Tobias

espruino-discuss3 · 2025-02-12T13:11:28Z

espruino-discuss3
Feb 12, 2025
Maintainer Author

Posted at 2015-02-10 by @gfwilliams

That sounds strange - how long does it take before the problem happens? Can you reconnect via USB afterwards? And when you do that does blinking resume again?

Maybe if you can log in when it happens, you could check getTime() and make sure that the value is rising at a rate of 1 per second.

I've set one up here with your code, so I'll see if I can get it to happen.

Posted at 2015-02-10 by net-tobi

Hi Gordon,

it is different. I recognized it for the first time after 3 hours. When I reconnected the USB it directly continued blinking. For shorter intervals (less than one hour) it happend faster.

I will set the interval a little shorter and try to log in when it happens again.

Best,

Tobias

Posted at 2015-02-10 by @allObjects

I noticed - on mistakes (miscoding) - on my part, when interval/timeout things repeat more often or get faster than expected, that I had multiple 'the same' intervals/timeouts running at the same time: my code created the same interval/timeout unintentionally again time skewed. From 'severely' glancing over the code I do not think this should happen in your piece of code, but give it a check... (log the interval id's and timeout id's you get when setting them together with the variable names you stick the interval into (---> i), and also which ones you clear... this may help you detect multiples running or exclude 'my theory' from being a possible cause).

(since you use an onboard LED, I exclude the option of an auto reset / brown out on power break down as have been noticed when LED strings - are run from the board's power or board supplying USB power (if not 8, then 9 RGB LEDs on full white will tear down a standard USB).

@gfwilliams, could it be that the timeout/s is/are not 'completed' when the deep sleep set's in which the deep sleep 'command' resides? ...or some reentrant issues in timing code... I guess I goe on wild goose chase and fishing in a muddy pond (muddy for me ignorant, crystal clear for you as the creator, @gfwilliams!)

Posted at 2015-02-10 by @gfwilliams

Actually setDeepSleep doesn't sleep immediately, it just sets a flag. You only actually need to call it once in the whole program, so any subsequent calls don't do anything.

I'm not really sure what the issue could be - my only guess so far would be that it's using the external real-time clock, and that it's unstable - either stopping, or oscillating wildly causing time to run too quickly. It's just a guess though - it's very hard to know anything without a bit more info.