[SOLVED] capacitor values for 4MHz oscillator 89s52

[nuwands]

I'm hoping to use a 4mhz crystal oscillator for 89s52. What is the capacitor values to be attached to the crystal? What will be the consequences of using such a small frequency crystal? can anyone please help me...?

 

[bigdogguru]

The AT89S52 Datasheet recommends 30pF for crystals.

However, the value is largely dependent on the crystal itself, specifically the stated Load Capacitance of the particular crystal.


Deviations from the appropriate value of capacitors will can the frequency of oscillator to either increase or decrease from the specified frequency of the crystal.

A lower frequency crystal will increase the instruction cycle, in effect increasing the time to process the same instruction.


BigDog

 

[asimov_18]

use 22pf and 33pf they are easily available.

 

[nuwands]

Thank you bigdogguru and asimov. Your answers gave me courage to play with it.

 

[bigdogguru]

The important point is to use the same value for both of capacitors, capacitors in the 22pF to 33pF range should provide a good oscillation close to the specified frequency of the crystal.

The following document, while AVR centric has a section concerning crystal oscillators which equally applies to the AT89S52:

AVR042: AVR Hardware Design Considerations

If you have any other issues post them here.

 

[pasicr]

It is not a problem,
mcu will be work with 10pF, 22pF, 30pF...
depends what you have in hand...
regards

 

[nuwands]

My question is solved. thank you all for your answers.