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Stopwatch Function — Parallax Forums

Stopwatch Function

ArchiverArchiver Posts: 46,084
edited 2002-01-04 17:57 in General Discussion
Hi All

I'm still trying to get a clean solution to my stopwatch function. I
need a .01 second resolution, 240 second minimum capacity stopwatch
for my stamp project. In a pinch, I can use .1 second resolution.

Best I have come up with is a crystal oscillator, a frequency divider
chip, and a PAK VII pulse coprocessor chip. This seems like an awful
lot of hardware.

Anyone have any other ideas?

Thanks
Duncan Potter

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-01-04 15:20
    Why not use a RTC chip with .01 sec res (8583?) and to start the stopwatch,
    set it to midnight.
    Then read the time at the desired moment. Gives you .01sec res stopwatch up
    to 23:59:59.99.
    Or have I misunderstood you?
    Regards
    Les Otter
    Original Message
    From: diacon1208 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CuiH7yd0WfmvPdNxbfZobESzepDhpl4pUsN65vGKoWoihB6wDEZsJqCwjFPMJvlKdYqJFEneECaNALMS]dpotter@d...[/url
    Sent: 04 January 2002 15:15
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Stopwatch Function


    Hi All

    I'm still trying to get a clean solution to my stopwatch function. I
    need a .01 second resolution, 240 second minimum capacity stopwatch
    for my stamp project. In a pinch, I can use .1 second resolution.

    Best I have come up with is a crystal oscillator, a frequency divider
    chip, and a PAK VII pulse coprocessor chip. This seems like an awful
    lot of hardware.

    Anyone have any other ideas?

    Thanks
    Duncan Potter


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  • ArchiverArchiver Posts: 46,084
    edited 2002-01-04 16:07
    That's exactly what I'm looking for. Guess I just didn't look hard
    enough! I'm assuming that the I2C bus is usable with the stamp. (I'm
    having a little trouble downloading the pdf sheet from phillips). I
    think that's going to do it for me. Thanks!

    --- In basicstamps@y..., "Les Otter" <lesotter@s...> wrote:
    > Why not use a RTC chip with .01 sec res (8583?) and to start the
    stopwatch,
    > set it to midnight.
    > Then read the time at the desired moment. Gives you .01sec res
    stopwatch up
    > to 23:59:59.99.
    > Or have I misunderstood you?
    > Regards
    > Les Otter
    >
    >
    Original Message
    > From: diacon1208 [noparse][[/noparse]mailto:dpotter@d...]
    > Sent: 04 January 2002 15:15
    > To: basicstamps@y...
    > Subject: [noparse][[/noparse]basicstamps] Stopwatch Function
    >
    >
    > Hi All
    >
    > I'm still trying to get a clean solution to my stopwatch function. I
    > need a .01 second resolution, 240 second minimum capacity stopwatch
    > for my stamp project. In a pinch, I can use .1 second resolution.
    >
    > Best I have come up with is a crystal oscillator, a frequency
    divider
    > chip, and a PAK VII pulse coprocessor chip. This seems like an awful
    > lot of hardware.
    >
    > Anyone have any other ideas?
    >
    > Thanks
    > Duncan Potter
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@y...
    > from the same email address that you subscribed. Text in the
    Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2002-01-04 17:57
    There are some additional links and software timing loops at
    http://www.emesystems.com/BS2speed.htm#longpulse

    The P. Anderson 8-pin timer chip resolves 1 millisecond in 1 hour.

    With a little calibration, a software timing loop could do the timing
    with no external hardware (provided your program does not have to do
    anything fancy while the stopwatch is running).

    -- regards,
    Tracy Allen
    electronically monitored ecosystems
    mailto:tracy@e...
    http://www.emesystems.com



    >Hi All
    >
    >I'm still trying to get a clean solution to my stopwatch function. I
    >need a .01 second resolution, 240 second minimum capacity stopwatch
    >for my stamp project. In a pinch, I can use .1 second resolution.
    >
    >Best I have come up with is a crystal oscillator, a frequency divider
    >chip, and a PAK VII pulse coprocessor chip. This seems like an awful
    >lot of hardware.
    >
    >Anyone have any other ideas?
    >
    >Thanks
    >Duncan Potter
    >
    >
    >To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    >from the same email address that you subscribed. Text in the
    >Subject and Body of the message will be ignored.
    >
    >
    >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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