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Problem using Quartz crystal 12Mhz with LPC2378

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vvenky88

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Hi friends,
I am using 12 Mhz Quartz crystal with 33pf capacitor for LPC2378..I am checking the frequency in the two pin of Quartz crystal but i am not able to get the frequency at the pin...
The same Quartz crystal with 33pf capacitor i am using with 8051 at that time i am getting the frequency...
The difference in 8051 and LPC2378 is operating voltage that is LPC2378 operating voltage is 3.3V and 8051 operating voltage is 5V....I am using the same Quartz oscillator for the both...
Now, My doubt is whether we need to choose a Quartz crystal depends only on frequency or depends on frequency and voltage?
Kindly guide me...
Thanks in advance....

regards,
Venky
 

ckshivaram

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can you specify the mode you have used to connect the crystal...
1. oscillation mode of operation,
2. external crystal model.

the capacitor value seems to be correct. but you should get around 0.9V on 1 pin and 0.7 in another pin.....
 

vvenky88

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can you specify the mode you have used to connect the crystal...
1. oscillation mode of operation,
2. external crystal model.

the capacitor value seems to be correct. but you should get around 0.9V on 1 pin and 0.7 in another pin.....

I am using external 12Mhz quartz crystal...

Actually in board, Only LPC2378 is soldered and 12Mhz quartz crystal is soldered with 33pf capacitor...What i am doing is, just i am checking the output frequency of the quartz crystal using Oscilloscope...But i am not able to get the waveform in the frequency of 12Mhz???This is only problem...

regards,
venkat
 

ckshivaram

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check the physical connection of the crystal to pin of controller. and replace the crystal if the crystal does not oscillate.... replace it with the crystal you told in 8 bit board or put this in that board and see if it works in the other board.........
 

vvenky88

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check the physical connection of the crystal to pin of controller. and replace the crystal if the crystal does not oscillate.... replace it with the crystal you told in 8 bit board or put this in that board and see if it works in the other board.........
OK...Tomorrow i will try and tell you the results..Thanks..

regards,
Venkat
 

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