Subject:
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Re: Interesting BrickOS Timing Results
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Wed, 15 Jan 2003 00:41:23 GMT
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Viewed:
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3378 times
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Dick Swan <dickswa@sbcglobal.net> wrote:
> I'm not sure of the need for the 6 us delay; in my homebrew OS I cut off
> power and immediately start A/D conversion and don't seem to have any ill
> effects.
The delay was added a long time ago after a bit of discussion on this
newsgroup/list. A search through old newsgroup posts will turn up a brief
series of three posts with subject "Rom sensor read routine" from Apr/May
1999. The explanation lies in those posts.
The reason for the delay was to let the values settle. Rotation and light
sensors need time to settle, otherwise their values will vary significantly
across the sensor ports. As I recall, Markus added in the delay after this
discussion.
Interestingly, the whole issue of LegOS hammering the sensors was mentioned
in the same thread...
-Kekoa
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Message is in Reply To:
| | Re: Interesting BrickOS Timing Results
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| This was a terrific analysis. It's not surprizing that current implementation hogs so much CPU time. If all four A/D channels are scanned every 150 us then the A/D interrupt is occuring every 37.5 us since each A/D channel generates its own (...) (22 years ago, 14-Jan-03, to lugnet.robotics.rcx.legos)
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