oscillator problem

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  1. - 4th September 2010, 09:34 #1
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    Quote Originally Posted by mackrackit View Post
    Melt the solder where?

    But what if you try MCLR as an input? Or are you?
    If I melt the solder that connects the crystal's pins to the pcb it works for a while. I assume it's because it's heating up the crystal?.

    Currently I have MCLR enabled, and have a 10k resistor pulling it high.
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  2. - 4th September 2010, 09:44 #2
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    Quote Originally Posted by Kamikaze47 View Post
    If I melt the solder that connects the crystal's pins to the pcb it works for a while. I assume it's because it's heating up the crystal?.

    Currently I have MCLR enabled, and have a 10k resistor pulling it high.
    Hi, Kamikaze

    No decoupling capacitors anywhere ??? ... especially the magic 0.1µF between supply pins ???

    Further ... having your config header could have helped, but surely "Top secret matter"

    Waiting for more infos ...

    Alain
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  3. - 4th September 2010, 10:03 #3
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    Quote Originally Posted by Acetronics View Post
    No decoupling capacitors anywhere ??? ... especially the magic 0.1µF between supply pins ???
    Further ... having your config header could have helped, but surely "Top secret matter"
    Yes there is a 0.1uF cap close to the VCC pin from there to ground. There is also a 100uF cap at the point that the supply enters the board (board is supplied by an external 5v source).

    config:
    Code:
            __CONFIG    _CONFIG1H, _HSPLL_OSC_1H
        __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        __CONFIG    _CONFIG3H, _MCLRE_ON_3H
        __CONFIG    _CONFIG4L, _LVP_OFF_4L
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  4. - 4th September 2010, 10:36 #4
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    Just to be sure, I just added another 0.1uF cap directly across the supply pins of the pic and it didnt help.

    I've also turned off MCLR, but also no luck.

    I've also just tried replacing the PIC but same issue.

    I'm stumped.
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  5. - 4th September 2010, 10:45 #5
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    OP should read:

    I'm running an 18f1320 at 40mhz using a 10mhz crystal with PLL enabled.

    The oscillator worked fine on a breadboard, but when I built a PCB for it, it worked for a while and then stopped working.

    It works again for a little while if I melt the solder points for the oscillator with my soldering iron, but 20 mins later it stops working again.

    Ive attached the PCB design. Anyone have ideas?
    Acetronics, can you edit it? I dont seem to be able to any more.
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  6. - 4th September 2010, 11:09 #6
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    Quote Originally Posted by Kamikaze47 View Post
    Yes there is a 0.1uF cap close to the VCC pin from there to ground. There is also a 100uF cap at the point that the supply enters the board (board is supplied by an external 5v source).

    config:
    Code:
            __CONFIG    _CONFIG1H, _HSPLL_OSC_1H
        __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        __CONFIG    _CONFIG3H, _MCLRE_ON_3H
        __CONFIG    _CONFIG4L, _LVP_OFF_4L
    Could you try

    Code:
    @ __CONFIG _CONFIG1H, _IESO_OFF_1H & _FSCM_OFF_1H & _HSPLL_OSC_1H
@ __CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_OFF_2L & _BORV_27_2L
@ __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_32K_2H
@ __CONFIG _CONFIG3H, _MCLRE_ON_3H
@ __CONFIG _CONFIG4L, _DEBUG_OFF_4L & _LVP_OFF_4L & _STVR_OFF_4L
@ __CONFIG _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L
@ __CONFIG _CONFIG5H, _CPB_OFF_5H & _CPD_OFF_5H
@ __CONFIG _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L
@ __CONFIG _CONFIG6H, _WRTC_OFF_6H & _WRTB_OFF_6H & _WRTD_OFF_6H
@ __CONFIG _CONFIG7L, _EBTR0_OFF_7L & _EBTR1_OFF_7L
@ __CONFIG _CONFIG7H, _EBTRB_OFF_7H
    as a config , to be sure of.

    Alain
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************
  7. - 4th September 2010, 11:15 #7
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    Quote Originally Posted by Acetronics View Post
    Could you try
    ...
    Unfortunately, no difference.
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  8. - 4th September 2010, 12:09 #8
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    Quote Originally Posted by Kamikaze47 View Post
    Unfortunately, no difference.
    did you clean the board carefully with acetone to wipe off any solder stripper ??? especially under the caps ...

    next step will be verify your caps value ( SMD not marked ...) and Xtal data ...

    may be could we have an eye on your program ??? ...

    Alain

    BTW ... could you try to run the PIC @ 10 mhz ( HS_OSC ) ... just to see if any life aboard.
    Last edited by Acetronics2; - 4th September 2010 at 12:12.
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************
  9. - 4th September 2010, 12:27 #9
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    Quote Originally Posted by Acetronics View Post
    did you clean the board carefully with acetone to wipe off any solder stripper ??? especially under the caps ...

    next step will be verify your caps value ( SMD not marked ...) and Xtal data ...

    may be could we have an eye on your program ??? ...

    Alain

    BTW ... could you try to run the PIC @ 10 mhz ( HS_OSC ) ... just to see if any life aboard.
    I did clean the board thoroughly with alcohol to get rid of flux, etc.

    Ive tried every cap value I have. At the moment I've actually replaced the SMD caps with 22pF thru-hole caps soldered onto the SMD pads as a test, but that didn't help either.

    Unfortunately I dont have data on my crystal. The place I bought it didn't supply data or a specific manufacturer/model number.

    When this started happening I reduced my program to a bare minimum to test if it is running. After trying 10mhz with HS_OSC (which didnt make a difference), the code im using is:

    Code:
    DEFINE OSC 10

ADCON1=%01111111

LCD_DB4         VAR PORTA.4
LCD_DB5         VAR PORTA.2
LCD_DB6         VAR PORTA.3
LCD_DB7         VAR PORTB.0
LCD_RS          VAR PORTA.0
LCD_E           VAR PORTA.1
LCD_Lines       CON 2    
LCD_DATAUS      CON 50 
LCD_COMMANDUS   CON 2000

INCLUDE "LCD_AnyPin.pbp"

PAUSE 200

LCDOUT $FE,1,$FE,2,"Hello World!"

END
    "I think fish is nice, but then I think that rain is wet, so who am I to judge?" - Douglas Adams
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