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 06:05:47 GMT
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Viewed:
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2898 times
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Joe,
That's definitely an improvement! So, that would be a
250 Hz sample rate for any given sensor. I just tried a
modification similar to yours that did all 4 conversions
every OCRA/B interrupt (or 1 KHz sample rate) and got:
IDLE: 82
2ROT: 77
NOAD: 93
NIRQ: 98
This sample rate should be more than enough for most
applications. If someone needs a higher sample rate, then
there could be a system call to enable faster sampling.
Looking at the code in sys_time.c, it seems possible
that the OCRB interrupt could be consolidated with the
OCRA interrupt, freeing the OCRB interrupt to be
used for sample rates > 1 KHz.
Mark
"Joseph Woolley" <jwoolley@spamblock.insight.rr.com> wrote:
> I retrieved the latest BrickOS from CVS, made clean and made the cpu
> test program you listed.
>
> I then made two small changes (to see what would happen); first the
> results, then the changes:
>
> IDLE: 89
> 2ROT: 87
> NOAD: 91 (see below)
> NIRQ: 98 (see below)
>
> Ok, this looks promising, here is what I did. This is the most simple
> change I could think of on short notice 8-)
>
> I commented out the line:
> bset #0x5,@_AD_CSR:8 ; go!
> at the end of the ds_handler; so now the A/D convertion doesn't start up
> again (yet)
>
> Then I added the same line to the end of the systime_handler. This
> starts the A/D conversion every 1 msec.
>
> OK, so this is not the end-all solution, but it is a good start IMO.
> The interval should be user selectable (maybe) at run-time. However,
> the numbers are much higher with this simple change. I would love to
> test it with the rotation sensor at various speeds (motor x 1, motor x
> 2, x 3, etc..) to see how it performs in comparison with the original
> method. However, I don't have time right now.
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Message has 1 Reply:
 | | Re: Interesting BrickOS Timing Results
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| (...) Timer B is usually unused but has a lower priority than Timer A. If you do a lot of stuff in the timer A routine, this will block timer B interrupts (especially if timer B generates more interrupts than timer A). The mean thing is that those (...) (21 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: Interesting BrickOS Timing Results
|
| Mark, I retrieved the latest BrickOS from CVS, made clean and made the cpu test program you listed. I then made two small changes (to see what would happen); first the results, then the changes: IDLE: 89 2ROT: 87 NOAD: 91 (see below) NIRQ: 98 (see (...) (21 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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