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RTC Accuracy

serdar
Intellectual 390 points

Other Parts Discussed in Thread: OMAP-L138

Hi All,

I need RTC with 0.5sec/day accuracy. I couldn't find detail about RTC accuracy in the datasheet. Can I reach this accuracy with L138?

What does TI recommend for RTC Crystal ESR and Capacitor?

 

Thanks in Advance

  • 0
    TI__Genius 14545 points

    serdar uludag said:
    I need RTC with 0.5sec/day accuracy. I couldn't find detail about RTC accuracy in the datasheet. Can I reach this accuracy with L138?

       

     

    The RTC has a trim register that you can write to to either add or remove extra ticks (if necessary to maintain accuracy due to variations with drift.). This is outlined in the RTC User Guide of the OMAP-L138. Also - just FYI Inherently the XTAL will also drift over time with aging, heat, impurities etc.

    serdar uludag said:
    What does TI recommend for RTC Crystal ESR and Capacitor?

    Typically the Crystal that is chosen will dictate the capacitor specs. The recommendation really depends on the size, form factor, cost you are willing to pay for the accuracy. As far as I'm aware - we don't have one recommended crystal - however if you are looking for a part number - you may choose to reference the Hawkboard (build around the OMAP-L138) which is available at hawkboard.org. The schematics & BOM are free for download.