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To be honest, not sure if it's actually fixed, I'm still seeing some occasional rippling on the digital output from the teensy. I'm not 100% convinced it's the logic analyzer, this ripple is...

sending rtc.enablePeriodicUpdateInterrupt(true, false); causes the rtc to make a 1hz interrupt on the INT pin.

Not sure why yours does this, weak signal so suffering from long cables perhaps? I...

My additions to the mentioned sketch were essentially


RV3028 rtc;
bool connectToRTC()
{
// RTC power and ground
pinMode(17, OUTPUT);
pinMode(21, OUTPUT);
digitalWriteFast(17,...

@defragster I just tried your script from #23 and I'm not seeing the same bounce, at least for this short time period:


Waiting for PPS toggle ...

us 2389086 cyc diff 1537 err= 2.56 us...

At least I think that's the case, hard to say whether the logic analyzer is wrong when I base my "correct-ness" on the logic analyzer output :)

I'm not sure before/after would show much, my cable...

regarding the original thread, after some inspection of both analog and digital channels in my logic analyzer, it seems likely that this was noise in the digital measurements. Very anticlimactic

From what I've read the teensy's inbuilt RTC crystal is rated worse (20ppm I think), though I've read of people demonstrating as low as 8ppm performance, think that was a post from you actually.

...

micros_from_second is only accessed in the callback and the ISR, but actually it's not so important because the described behavior happens when I comment it out as well, still working on the...

What's going on in line 463 of your csv? Formatting of the time[s] becomes a bit interesting. Otherwise mine uses more or less the same format, so the python script should be usable.

...

Fair enough, I'm lucky enough mine can take measurement over a range, so it calculates all of these metrics for me. I have a python script for the same, but I'm not sure how much use it will be if...

I thought I posted a response to KurtE but I see it didn't go through.
The response was that I had tried commenting out the Serial.write line and that the error was still happening after approx 100s...

My reading side is typically a c++ program which, should, read everything as it comes. At least it looks that way. But when i was capturing the data which I used for the plots above and to check the...

Sorry for spamming this thread. I've managed to create a test case which fails the same way, first run was successful, second run resulted in 200Hz f_max over 1kHz and the 10Hz signal having a std...

It's one of three periodic callbacks (each associated with an intervaltimer) which has these delays. It happens in larger degree to the low frequency ones, but all three suffer (almost...

Here are some figures I made illustrating all sampling times > 1 std deviation from the mean
302623026330264

Note these are all grouped, and many of them happen when all three triggers fire on...

I'll try and get back to you with a simple example, as I said it's not necessarily extremely regular.

For example, for the 10Hz timer I processed the data in python and the following is the first...

Following

https://forum.pjrc.com/threads/71506-Time-synchronization-and-triggering-sensors
https://forum.pjrc.com/threads/71671-Augmenting-Teensy-millis-timing-with-external-RTC

I am working...