[SOLVED] What is the difference between a crystal and an oscillator

[keith1200rs]

VSS should be connected. OSC2 unconnected (I think you may be able to get a buffered clock output from it if you want).

Keith.

 

[neazoi]

VSS should be connected. OSC2 unconnected (I think you may be able to get a buffered clock output from it if you want).

Keith.

apologize for the silly question but where should the vss be connected? to the +v of the crystal oscillator module?

 

[keith1200rs]

No, VSS is GND or 0V.

Keith.

 

[neazoi]

No, VSS is GND or 0V.

Keith.

Thank you very much!
Just to summarize I have attached a picture. Seems ok?

 

[keith1200rs]

Yes, that looks ok. It is normal to add a decoupling capacitor across the oscillator power pins. Also watch out - a lot of oscillators have an enable pin.

Keith

 

[neazoi]

I checked out my programmer software. It has only LP XT HS RC options for oscillator. How can I tell the software that I want to use external oscillator then?

 

[keith1200rs]

Looking at the data sheet for that PIC, it seems that you can use LP, HS or XT modes with an external clock.

Keith.

 

[kandhu26]

Re: difference between crystal and oscillator

OSCILLATOR:
The circuit capable of producing any type of signal with similar amplitude, wave shape and frequency without any input.. Eg: Sine wave, sawtooth etc..

CLOCK OSCILLATOR:
A circuit capable of producing square wave output with uniform magnitude and frequency.. The frequency of oscillation and amplitude of the signal should be independent of supply voltage changes or environment changes like temperature, humidity etc..

CRYSTAL OSCILLATOR:
An Oscillator capable of producing a square wave using a crystal as feedback element that is called crystal oscillator..

 

[Syncopator]

Crystal is a piece of mineral, of which there are many types.

An oscillator is a circuit, or other device, which produces a repetitive output or waveform.



The former is used in elctronics in the form of Rochelle salts used in, for example, microphones, and in the form of quartz which may be used in filters and oscillators.


An electronic oscillator may have its frequency governed by a combination of resistance and capacitance, a combination of capacitance and inductance or by a quartz crystal.