Generally a quartz crystal is used for generating clock timing for micro controllers. Why? Because of precision or some other reason?

 

Generally a quartz crystal is used for generating clock timing for micro controllers. Why? Because of precision or some other reason?

Accuracy and stability. It is quite easy to manufacture oscillators with a quartz crystal that work at a given frequency plus or minus some small error. The frequency is stable over time, temperature, and supply voltage variations.

 

What exactly is this accuracy? It is compared with what? Please advise.

 

What exactly is this accuracy? It is compared with what? Please advise.

Well, start with the datasheet for a typical crystal oscillator with a frequency of 4 MHz:

https://www.mouser.com/datasheet/2/121/EC5720ETTS-4_000MTR-1011893.pdf

The accuracy and stability are specified as 20 ppm (parts per million). You would compare this to a specifications for a ceramic resonator.

https://www.murata.com/~/media/webr...alog/products/timingdevice/ceralock/p16e.ashx

One possible specification calls for 0.07%

So 20 ppm on 4 MHz = ± 80 Hz. for the crystal oscillator
And 0.07% on 4 MHz = ± 2800 Hz.

Now compare either of those to an oscillator using passive components with let us say a ± 10% tolerance and you begin to appreciate the differences.

 

The Crystal in my digital watch, the quartz one not the face cover! Typically 32,768Khz, has lost <1min. in the last 6 years when I had changed the battery last.
Max.

 

Because clock timing signals and binary signals need to be synchronized.
The ability to program MEMS chips can be compared to quartz.for accuracy.
Better off to keep it simple. An analogy would add unnecessary and irrelavant detail.
The oscilloscope channels tell us what is going on and the glitches can slow processing.

 

Because clock timing signals and binary signals need to be synchronized.
The ability to program MEMS chips can be compared to quartz.for accuracy.
Better off to keep it simple. An analogy would add unnecessary and irrelavant detail.
The oscilloscope channels tell us what is going on and the glitches can slow processing.

NONE of these comments relate to the discussion in this thread, not at all. Using a crystal oscillator is not what synchronizes signals, and MEMS devices have not been mentioned here at all. It seems that sparky has got into the wrong thread.

 

This thread did not need to be resurrected either. Just let it drift into obscurity.