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Pause duration — Parallax Forums

Pause duration

ArchiverArchiver Posts: 46,084
edited 2003-12-22 03:22 in General Discussion
Hi,

I just checked the PAUSE duration with the oscilloscope. Is shows
that the 'Duration' actually increments in 3msec intervals (not 1 ms
as suggested in Help). So 'Pause 1' gives 3ms, 'Pause 2' - gives 6
ms etc. 'Pause 0' command gives approx. 0.7 ms delay.

Other approach I tried is:

FOR i=0 to Duration: NEXT

-gives approx. 2,2ms delay increments. Unforunately the minimum
delay obtainable is 2,2ms as FOR:NEXT loop is executed at least once.


Q. is there any way to get a shorter pause, say <=1ms?

Sincerely,
Boris

Env. BS2 (BASIC Stamp Homework Board), WinXP
PBASIC 2.5
Editor 2.0 beta2

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-12-22 03:22
    With respect, I think you may be reading your scope's SEC/DIV dial
    incorrectly. I just ran this little program:

    Main:
    DO
    HIGH 0
    PAUSE 2
    LOW 0
    PAUSE 5
    LOOP

    END

    And found that the actual high pulse output is about 400 uS (0.4 ms)
    longer than the PAUSE duration -- this is due to EEPROM access and setup
    for both the PAUSE and LOW instructions. I tried with several values
    with consistant results.

    Dr. Tracy Allen has done extensive testing on instruction timing and has
    documented in nicely on his web site. Have a look:

    http://www.emesystems.com/BS2speed.htm


    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: odissey2 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=WfMddCSHUKfLZhGHj2I-hTYD6h-2OSf66GbKTC9Huuq6TsM9ZraIM90V1AobbGn9VcYr2oksGOBa]botadjik@n...[/url
    Sent: Sunday, December 21, 2003 3:25 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Pause duration


    Hi,

    I just checked the PAUSE duration with the oscilloscope. Is shows
    that the 'Duration' actually increments in 3msec intervals (not 1 ms
    as suggested in Help). So 'Pause 1' gives 3ms, 'Pause 2' - gives 6
    ms etc. 'Pause 0' command gives approx. 0.7 ms delay.

    Other approach I tried is:

    FOR i=0 to Duration: NEXT

    -gives approx. 2,2ms delay increments. Unforunately the minimum
    delay obtainable is 2,2ms as FOR:NEXT loop is executed at least once.


    Q. is there any way to get a shorter pause, say <=1ms?

    Sincerely,
    Boris

    Env. BS2 (BASIC Stamp Homework Board), WinXP
    PBASIC 2.5
    Editor 2.0 beta2



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