markuslange / rtcdue Goto Github PK

Many libraries that use UTC or unixtime contain subtle bugs in determining the correct calendar date/time and parsing/math errors when presented with a date/time like 20yy1231T115960Z. I strongly suspect (but haven't tested) that the Arduino RTC_ routines are also flawed in this manner, rendering them naively-buggy if using UTC directly as a time source; however, using RTC_ with TAI would be fine since there would be no leap seconds.

Reasons:

• UTC contains leap seconds, TAI doesn't. [1]
• TAI doesn't have horrific edge-cases like 61 second minutes, so a correct implementation using TAI is much simpler.
• A downside to converting TAI <---> UTC requires a current leap-second table that can and will change over the years.
• Converting TAI <---> unixtime is straightforward, as-if there were no leap seconds.

Users can either:
A. Periodically set their embedded system's RTC to TAI from a reliable external source after converting to TAI with a proper library. [2]
B. Assume the risks of UTC and simply don't do correct interval measuring, don't store correct date/times in the past, and don't require correct, monotonic time.

References:

1. TAI/UTC https://cr.yp.to/proto/utctai.html
2. libtai https://cr.yp.to/libtai.html
3. Future leap second news https://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat
4. Leap second text table https://raw.githubusercontent.com/eggert/tz/master/leap-seconds.list
5. Leap second binary table https://cr.yp.to/libtai/leapsecs.dat

Hello. Would you like to comment on the methods in the code?

Looks like there's a broken include @ RTCDue.h

#include <include/rtc.h>

Newbie to CPU programming here. I'm trying to use the SAM3X's low-power backup mode to reduce energy consumption on my Due. One of the ways that the CPU can be woken is with an interrupt signal from the RTC, which is not turned off in backup mode. Ideally, I'm trying to do this routinely(Every X seconds) and I'd like to know if that is possible using this repo. Atmel has sample code for this but it's inaccessible because I'm on macOS. Thank you!

tried it and could not not make work with arduino 1.8 , serial.begin is not working ? please advise

Hello,

The RTCDue library code occasionally gets stuck on the following line of code(usually when attempting to set the time right after calling rtc.begin() ):

while ((RTC->RTC_SR & RTC_SR_SEC) != RTC_SR_SEC);

This is according to the atmel ICE debugger, and I am a bit lost as to why this is only occurring some of the time. This line seems to be waiting for a tick to occur that never comes?

I need to know what this library is used for. I uploaded the RTCDue_Simple_Sample trial program to my arduino and nothing was written out on the serial monitor and the board has not been communicating ever since. The programing port logs in but nothing can be loaded into the board. Can you please help me?