Hi, I wonder if anyone knows if it is possible to have alarm on the DS3231 RTC module that works by setting the SQW pin high and low for extended periods of time? I have used the DS3232RTC library to set interrupt alarms as talked about here Link and that worked just fine. But that, I think, uses …

It's my understanding that when an alarm is triggered, the INT/SQW pin goes low, and it stays that way until the appropriate register is cleared in the DS3231. If that's right, it's not a pulse, and it would be under your control as to when it goes back high, but you would have to issue that command…

What are you doing with these pulses, and with the rest of the system? Without some context, it's hard to give useful advice because your ideas are basically non-starters.

aarg: Have you read the DS3231 data sheet? Great advice! I should have looked before asking here... Lesson learned. :slight_smile: Anyway, here is what I found with regards to this pin: Active-Low Interrupt or Square-Wave Output. This open-drain pin requires an external pullup resistor connecte…

The question now is how to code this How to code what? The specification you gave us was extremely vague. You haven't explained what it is for, either. So far all that you've shown is that you can make a periodic pulse on the SQW pin. That's well documented but it seems you want to do more? You …

aarg: What are you doing with these pulses, and with the rest of the system? Without some context, it's hard to give useful advice because your ideas are basically non-starters. Good point. I should have explained the context. I would like to turn the power on and off to my project (Uno and oth…

You might find some answers in reading about the DS3231 library, DS3231 - Arduino Reference . You'll notice a link on that page, you'll want to follow that link, after reading the page. You'll be able to get to example code. And if you want to get to the nitty and grit of the module you'd look at a …

Idahowalker: You might find some answers in reading about the DS3231 library, DS3231 - Arduino Reference . You'll notice a link on that page, you'll want to follow that link, after reading the page. You'll be able to get to example code. And if you want to get to the nitty and grit of the module y…

Yea, the data sheet has a good description of how it works. https://datasheets.maximintegrated.com/en/ds/DS3231.pdf

The INT/SQW pin is always high until the alarm is triggered. What's resetting the alarm in your example is the RTC library code. When you call the "alarm" function to see which alarm has been triggered, that function also clears the alarm flag, which lets the pin go back high. I probably wouldn't h…

DS3231 RTC module SQW pin: High/low for extended time?

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anon57585045 November 22, 2020, 5:53pm 2

Have you read the DS3231 data sheet?

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DS3231 RTC module SQW pin: High/low for extended time?

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