What does 'DC' in DC-20 Mhz operating frequency of a microcontroller means?

Discussion in 'General Electronics Chat' started by viznu3391, Feb 15, 2016.

  1. viznu3391

    Thread Starter New Member

    Dec 10, 2015
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    Can anyone please tell what does DC in oscillator specification of a microcontroller means ?
     
  2. Alec_t

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    Sep 17, 2013
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    Direct Current, i.e. 0Hz.
     
  3. viznu3391

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    Dec 10, 2015
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    This is where I get confused. since oscillator is running in 20MHz frequency, then what does this 0Hz implies?
     
  4. jpanhalt

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    Jan 18, 2008
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    "0 Hz" means that the MCU is specified down to DC for its clock. Now, a DC "clock" might not be useful, but you might want to use an external clock at a much lower frequency than, say 32 kHz. Maybe for some applications something as slow as 10 to 100 Hz might have a use. You can also clock through a program at a very slow pace.

    John
     
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  5. viznu3391

    Thread Starter New Member

    Dec 10, 2015
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    Thanks for the quick reply.I didn't think in the way that it is actually specifying the range of frequencies it can operate.

    Thanks all
     
  6. hp1729

    Well-Known Member

    Nov 23, 2015
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    It implies that the clock signal can be stopped without loosing operations. Older processors had a minimum clock frequency. I have never tried it but you might be able to step a processor through operations at a manual clock speed if it says that it goes own to DC.
     
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  7. Papabravo

    Expert

    Feb 24, 2006
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    It also means you can stop the clock in either the high state or the low state for an indefinite period of time and then continue without losing any information. It requires that the internal circuitry be constructed with static memory. The opposite of static memory is dynamic memory which requires periodic refresh cycles or the bits just sort of disappear.
     
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  8. alfacliff

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    Dec 13, 2013
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    most of the processors are dynamic logic, they have to have a clock running. if the clock stops, the processor usually wither quits, or fails. the RCA 1802 is one of the early processors that actually was made with static logic, you could clock it with a switch, and it still worked if the clock stopped look up "static and dynamic logic".
     
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