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???
10/16/05 02:44
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#102462 - Can i have some clarifications on XTALS
Responding to: ???'s previous message
Hi,
I am a little bit confused by the RTC. Do we need to use a exact 32.768Khz crystal to have a proper RTC , or we can use a high frequency Crystal i.e. 8 Mhz and count exactly 8,000,000 clocks (in case we are using a single clocker drivative) for each second.
All i have read was about that Crystals have the lowest PPM offset.Also i have read that 32.768Khz Crystals are made with a better Q-factor,but there has to be good quality Mega-Hertz Crystals out there.

So can someone ,please tell me that can a 'Mega-Hertz Crystal' be used with the same performance of a '32K' Crystal for timing purposes.

Farshid

List of 19 messages in thread
TopicAuthorDate
Software Based RTC            01/01/70 00:00      
   Context            01/01/70 00:00      
      Link to my RTC - sftware crystal freq.            01/01/70 00:00      
   The precision is depending on the fracti            01/01/70 00:00      
   How to count seconds            01/01/70 00:00      
      How to decide count for a 3.5795Mhz,            01/01/70 00:00      
         the frequency range does not matter            01/01/70 00:00      
            the "tricks"            01/01/70 00:00      
         3.93216MHz is better            01/01/70 00:00      
            4.915200            01/01/70 00:00      
            3.93216 ??            01/01/70 00:00      
               3.93216 is standard frequency            01/01/70 00:00      
                  Can i have some clarifications on XTALS            01/01/70 00:00      
                     manufacturing tolerances            01/01/70 00:00      
                        low frequencies Crystals are bigger ?            01/01/70 00:00      
                     32.768kHz means low current consumption            01/01/70 00:00      
                        so higher Frequeny crystals are accurate            01/01/70 00:00      
                           Yes!            01/01/70 00:00      
   The Right Frequency            01/01/70 00:00      

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