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Alarm with Mémoire ?

Message non luPosté: Jeu 15 Déc 2011 16:22
de John Murray
I have an Arduino Uno and a Memoire RTC / SD card. Can I get the RTC alarm section on the Memoire card to generate a hardware interrupt for the Uno? If not, how can the Uno tell when the alarm has activated?

Thanks

John (UK)

Re: Alarm with Mémoire ?

Message non luPosté: Jeu 15 Déc 2011 17:09
de Lionel
Hello,

the RTC chip used for real time backup doesn't have this alarm output hardware implemented,

So, if you want this function, you'll have to program it by yourself.
For example you could ask the program to read the actual time every minut or second (depending what accuracy you need) and compare to an alarm time you previously decide.
I think you'll be able to find some existing alarm clock using DS1307 and arduino
there is one here : http://hacks.ayars.org/2010/01/alarm-cl ... rkill.html

hope it helps,

Re: Alarm with Mémoire ?

Message non luPosté: Jeu 15 Déc 2011 21:32
de John Murray
Thanks, Lionel. Perhaps I'll try using an edge of the 1Hz square wave to generate an interrupt on the Uno, and program an alarm from that.

John