Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [clock]

A digital signal that goes high and low at a specific frequency.

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Can microcontrollers be run at arbitrarily low clock frequencies?

The datasheet for the ATTiny13A, for instance, lists Min frequency of 0 MHz. Does this mean the clock can be run at any arbitrarily low frequency with no ill effects? I'm assuming it draws lower current at lower clock speeds? Does 0 MHz mean you…
endolith
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Serbia, Kosovo power grid row delays European clocks. Why?

According to this article (and a lot more published today on the same topic), Kosovo electricity net production balance has decreased during the last weeks. This has led to a small deviation of the European network’s frequency (from 50Hz to…
Evariste
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How do GPS satellites refresh their clocks

How do GPS satellites keep their on board clocks accurate? I assume that they need to get update from a base station. But how do you make sure that after the update all the satellites are synchronized, i.e. there isn't any phase shift. You have…
user110971
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How to synchronize two microcontrollers to micro-second accuracy?

I need to synchronize two micro-controllers so that they can measure the speed of propagating waves. The time delay measurements need have microsecond accuracy (error less that 1/2 of a microsecond). I have two micro-controllers (ATmega328) which…
Kevin
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Why do Microcontrollers need a Clock

Why do instructions need to be processed at set time intervals (i.e. with the use of a clock)? Can't they be executed sequentially - immediately after the previous instruction has completed? An analogy for the necessity of clocks in microcontrollers…
M-R
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How precise is the frequency of the AC electricity network?

If I make a digital clock which first detects the AC frequency roughly (whether it is 50, 60, 100Hz, etc), then uses it as its clock pulse source, how precise would it be? Would it work world wide precisely? For instance, in USA, what is the mean…
hkBattousai
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Why are clocks used in computers?

As I know, a clock controls all of the logic operations, but it also limits the speed of a computer because the gates have to wait for the clock to change from low to high or high to low depending on the component. If no clock was incorporated, the…
skyler
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Using the ATMega328 with the internal oscillator?

I have a project that I think would be best suited for an ATMega328P. However, in every simple project I've seen, people always hook up a 16MHz external oscillator. From what I can see, it should have an 8MHz internal oscillator. My project doesn't…
Earlz
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How do electronic devices keep track of time without power?

There's laptops, PCs, microcontrollers and a lot of other things that can be plugged out and plugged in without a battery. But how does the system clock still keep track of time without anything to power it?
Loogai
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Why edge triggering is preferred over level triggering?

I am trying to understand why edge triggering is preferred over level triggering. In my book it is not explained clearly. After searching online I came to know that edge triggering is insensitive to glitches whereas level triggering is sensitive.…
avi
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How to communicate faster than the system clock

I was reading about the new (ish) Thunderbolt 3 today, and was very impressed by the specced speed of 40Gbps. Then I looked at Intel's latest i9 processor speed... about 4.2GHz max. How can a system communicate almost 10 times faster than the clock…
Isaac Middlemiss
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How can a CPU dynamically change its clock frequency?

My Intel CPU changes clock speed depending on the usage, but how does it decide what clock speed to run at? Is the clock speed determined by the OS software using an algorithm, or is it hardware based? Is it dependent on the # of interrupts? The…
Chloe
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Why use DDR instead of increasing clock speed?

Why would you want to use DDR ram and read/write on every rising and falling edge of the clock instead of just doubling your clock speed and read/write on just one of either the rising or falling edge? Are there pros and cons to each?
Ethan
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How can I calibrate a retail digital clock that uses a 32.768 kHz crystal?

SOLVED: SEE BELOW ORIGINAL QUESTION FOR IMPLEMENTED SOLUTION I have two Sony Dream Machine clocks. They are different models; one seems to use the mains frequency and is keeping its time precisely, while the other (model: ICF-C414) seems to be using…
Duxa
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Why in 8085 microprocessor, the clock frequency is divided by two?

Why is it that the produced clock frequency is 6.144 MHz, but internally it (8085 processor) uses only 3.072 MHz. Also what leads to the specific value of 6.144 in a clock. I found an answer at yahoo....…
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