Timing verification.


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  1. #1
    Join Date
    Dec 2003
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    Wichita KS
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    Default Timing verification.

    Hello folks,

    I would like to have a quick verifcation on a program, or is it me missing a link in my head?

    The following program uses a pauseus statement
    If I use Pauseus 1, it has 28 micosecond delay between spikes.
    If I use Pauseus 5, it has 28 Microsecond delay between spikes.
    If I use Pauseus 3, it has 30 Microsecond delay between spikes.
    If I use Pauseus 10, It has a 28 Microsecond delay between spikes.

    If I use a PAUSE 1 it has a 1 millisecond delay (which is good)

    I probably have a screw loose upstairs that is baffling me on this situaion, and I have not figured it out yet.


    Here is the complete code to simulate this senario:

    @ DEVICE PIC12F675,INTRC_OSC_NOCLKOUT,WDT_ON,PWRT_OFF,BOD_O N,PROTECT_OFF,CPD_OFF,MCLR_OFF

    CMCON=%00001000
    TRISIO=%00000000


    Loop:
    GPIO=%00000001
    GPIO=%00000000
    pauseus 1 'replace this with the numbers mentioned above
    GOTO Loop
    end
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  2. #2
    carl_schell's Avatar
    carl_schell Guest


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    Cool

    Hi Dwayne -

    I would guess it might be related to resolution. The pbp manual says thet the minimum delay for lets say a 4 MHz resonator to your pic is about 24 micro seconds....so when you ask for less...you are asking for too short of a pause....switching to a 20 MHz resonator should increase your resolution down to 3 micro seconds.

    Best Regards,

    Carl

    -------

    PIC Development Boards with bootloader
    www.schellelectronics.com

    Novi, Michigan, USA
    Last edited by carl_schell; - 31st August 2004 at 05:48.

  3. #3
    Join Date
    Jul 2003
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    @ NOP

    Insert for 1uS Delay at 4MHz, 500nS delay at 8MHz etc etc.

  4. #4
    Join Date
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    Default

    Hello Carl and Melanie,

    Carl>>I would guess it might be related to resolution. The pbp manual says thet the minimum delay for lets say a 4 MHz resonator to your pic is about 24 micro seconds....so when you ask for less...you are asking for too short of a pause....switching to a 20 MHz resonator should increase your resolution down to 3 micro seconds. <<

    Thanks a million both of you. I guess I was assuming too much <g>. I knew there had to be something going on... I was up too late last night working on a stupid project... thank goodness there is not a time limit. <g>

    Dwayne
    Ability to Fly:
    Hurling yourself towards the ground, and missing.

    Engineers that Contribute to flying:
    Both optimists and pessimists contribute to the society. The optimist invents the aeroplane, the pessimist the parachute

    Pilots that are Flying:
    Those who know their limitations, and respect the green side of the grass...

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