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Real Time Clock drift with development board

Perry Frogge
Intellectual 370 points

My firmware guy is using development board "omap-l138-c6748 ver A6 and he sees 10msec  per second drift or inaccuracy with the real time clock, using c6748. Anecdotal evidence is he hears same issue from other users of this DSP at prior employer. We are getting ready to add a $10 RTC chip to the bom to solve this, any inputs are appreciated. 

thanks 

  • 0
    TI__Expert 7470 points

    Hi Perry,

    RTC drift that you are observing is not necessarily a function of the DSP but of the quality of the 32KHz crystal and it's immunity to temperature variations, power supply noise etc. Please see the following post for a similar discussion http://e2e.ti.com/support/dsp/omap_applications_processors/f/42/t/250381.aspx.

    If your application can work with the hourly auto compensation feature of the C6748 RTC, you could avoid adding the extra RTC chip. If you do not have access to an accurate clock signal such as PPS from a GPS chip, you might consider using the timer on the C6748 to calibrate the compensation registers.

    Regards,

    Sunil Kamath