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Reason for corruption of data from DS3232.

 
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jaikumar



Joined: 15 Dec 2006
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Reason for corruption of data from DS3232.
PostPosted: Thu Mar 17, 2011 12:10 am     Reply with quote
Hi All,

I am using a DS3232 with 18F2550 I2C. When i set the date and time it works. but when i switch on and off a few times either the date or time
gets corrupted. The value some times is even greater than 12 for month.

Data does not get corrupted as long as power is not switched on/off

Need help on what might be the causes.

Thanks and Regards,
Jai.

Last edited by jaikumar on Thu Mar 17, 2011 12:17 am; edited 1 time in total
bkamen



Joined: 07 Jan 2004
Posts: 1615
Location: Central Illinois, USA

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PostPosted: Thu Mar 17, 2011 12:17 am     Reply with quote
You do have a battery attached, yes?

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D
jaikumar



Joined: 15 Dec 2006
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PostPosted: Thu Mar 17, 2011 12:25 am     Reply with quote
Yes. Battery voltage is also fine.
jaikumar



Joined: 15 Dec 2006
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PostPosted: Thu Mar 17, 2011 12:54 am     Reply with quote
When using CCS ICD-U64 the MCLR pin is kept at 4.5 V. I removed the ICD connections during power cycle. The data has not got corrupted. Will test further to determine if this is THE cause.

regards
jai
jaikumar



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PostPosted: Thu Mar 17, 2011 1:42 am     Reply with quote
That was not the cause.
Any other ideas?

regards,
jai
temtronic



Joined: 01 Jul 2010
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PostPosted: Thu Mar 17, 2011 5:45 am     Reply with quote
Other things to look at.

Properly designed power supply,especially EMI filtering...

Enable PUT in Fuses...

Correct ground layout and local bypass caps, one per chip.

Correct pullups, based on Vdd and speed..
Ttelmah



Joined: 11 Mar 2010
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PostPosted: Thu Mar 17, 2011 6:07 am     Reply with quote
Take us through the supply circuitry, and the layout of the I2C connections (pullup values, do you have inline resistors as well?).

Best Wishes
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Mar 17, 2011 1:39 pm     Reply with quote
Quote:
I am using a DS3232

Maxim makes that chip. Look on their website for excellent appnotes
on how to use it. Look near the end of this appnote for suggestions
on fixing data corruption with RTC chips:
http://www.maxim-ic.com/app-notes/index.mvp/id/504
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