1307 RTC accuracy?

[skimask]

Same thing here... I've got a cheap watch that's wrapped around my rear view mirror year-round. Except for resetting it twice a year for daylight savings time, it holds time well, and we get wild temp variations up here. (and yes, the watch probably costs more than the car, at least you'd think so if you saw the car )

[Pic_User]

Thanks for the interesting discussion.

This is a handy online ppm calculator:
http://www.maxim-ic.com/tools/calcul...fm/calc_id/rtc

This calculator converts timekeeping accuracy measurements from parts per million (PPM) to real-time accuracy described in seconds per day and minutes per year.

[mackrackit]

The clock radio in my truck keeps good time also. Temperatures a little on the high side in SW Arizona.

I have noticed it will loose a bit of time on long trips. Normal short trips and it is fine.
Maybe it has something to do with speed and how long the speed is maintained changing time.

[Luciano]

I have noticed it will loose a bit of time on long trips.
Normal short trips and it is fine.
Maybe it has something to do with speed and how long the speed is maintained changing time.

Hi,

Einstein's Theory of Relativity?

* * *

Crystal Considerations with Dallas Real-Time Clocks (RTCs)
http://pdfserv.maxim-ic.com/en/an/AN58.pdf

Considerations for Maxim Real-Time Clock Crystal Selection:
http://pdfserv.maxim-ic.com/en/an/AN616.pdf

Best regards,

Luciano

[skimask]

Einstein's Theory of Relativity?

That's the answer! MAXIM makes their chips around 40 degrees north, the original post'er lives on the equator. The earth rotates faster at the equator... Makes perfect sense!