millis() good enough for a RTC

Forum 2005-2010 (read only) Software Bugs & Suggestions
1

Hi, I want to make an alarm clock with arduino, I'm thinking of using millis() to provide me a real time clock, are they acurate enough even if the main loop program takes more than a secound or so (I will write to a LCD, and that)?

Is there any way to use AVR's internal counters?

Thanks

2

NEDM64, the millis() mechanism is driven by interrupts, so even if your loop function is 30 minutes long the value of millis() will be pretty accurate. That said, it's accuracy is limited by the accuracy of the crystal.

M

3

Thanks

Now, I can throw away the 1Hz signal/RTC from the project :wink: