What capacitor is suitable for 20MHz crystal?

[June]

Dear all,

Hi, thanks for all ur help just now. U all are really expert in PIC. Because can answer almost all my questions. How u all learned it?

I'm here having a doubt on what is the suitable capacitor value for 20MHz crystal when using PIC16F876? Because the datasheet shows it can be from 15pF to 33pF. I don't know the larger the better or smaller the better. But at the moment I use 33pF type.

Hope to get your response soon. Thanks.

Regards: June,
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This message was ported from CCS's old forum
Original Post ID: 8971

[Gerrit Faas]

Hi june,

For exact frequency it depence on the cystal specs.
For my quick and easy boards I use 18 pF and until know
no problems.


Regards,

Gerrit


:=Dear all,
:=
:= Hi, thanks for all ur help just now. U all are really expert in PIC. Because can answer almost all my questions. How u all learned it?
:=
:= I'm here having a doubt on what is the suitable capacitor value for 20MHz crystal when using PIC16F876? Because the datasheet shows it can be from 15pF to 33pF. I don't know the larger the better or smaller the better. But at the moment I use 33pF type.
:=
:= Hope to get your response soon. Thanks.
:=
:=Regards: June,
___________________________
This message was ported from CCS's old forum
Original Post ID: 8972

[adimot]

:=Dear all,
:=
:= Hi, thanks for all ur help just now. U all are really expert in PIC. Because can answer almost all my questions. How u all learned it?
:=
:= I'm here having a doubt on what is the suitable capacitor value for 20MHz crystal when using PIC16F876? Because the datasheet shows it can be from 15pF to 33pF. I don't know the larger the better or smaller the better. But at the moment I use 33pF type.
:=
:= Hope to get your response soon. Thanks.
:=
:=Regards: June,

I use 18 pF.
But I had to change the crystal once to make it work. Try that yourself.
This is what I use :
#FUSES HS,NOWDT,NOLVP,NOWRT,NOPROTECT,PUT,BROWNOUT // PIC fuse settings.
Put a 100 nF capacitor near the power pins (19 and 20, GND and +5V). And ground both pins 8 and 19.
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This message was ported from CCS's old forum
Original Post ID: 8977

[Sherpa Doug]

Ask the manufacturer of your crystal.

:=Dear all,
:=
:= Hi, thanks for all ur help just now. U all are really expert in PIC. Because can answer almost all my questions. How u all learned it?
:=
:= I'm here having a doubt on what is the suitable capacitor value for 20MHz crystal when using PIC16F876? Because the datasheet shows it can be from 15pF to 33pF. I don't know the larger the better or smaller the better. But at the moment I use 33pF type.
:=
:= Hope to get your response soon. Thanks.
:=
:=Regards: June,
___________________________
This message was ported from CCS's old forum
Original Post ID: 8981

[Miguel Martin]

:=Dear all,
:=
:= Hi, thanks for all ur help just now. U all are really expert in PIC. Because can answer almost all my questions. How u all learned it?
:=
:= I'm here having a doubt on what is the suitable capacitor value for 20MHz crystal when using PIC16F876? Because the datasheet shows it can be from 15pF to 33pF. I don't know the larger the better or smaller the better. But at the moment I use 33pF type.
:=


Hi. At moment I use 22pF, SMD capacitor. You need some precautions in grounding these capacitors. The point to ground MUST be shortly to VSS pin of the chip. This avoid possibility of ground loops, and works correctly.

Bye.
WMMG
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This message was ported from CCS's old forum
Original Post ID: 9031

[June]

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This message was ported from CCS's old forum
Original Post ID: 9198