 | | Re: DISTRIBUTED/PARALLEL CLUSTER for legOS through n*RCX
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Just a question about this. Won't the IR airwaves will be a major bottleneck for most parallel applications? -Kekoa (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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OCRA and OCRB are output interrupts for the 16 bit timer. They can be programmed to fire at specific points along the timers run. So, technically, they cannot be used independently of each other. If OCRA resets the timer value back to zero, then (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | DISTRIBUTED/PARALLEL CLUSTER for legOS through n*RCX
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Hi all. I'm taking a course on parallel/distributed operating systems. So this post attempts to find out if someone has thought, or has implemented some kind of distributed application over BrickOS/legOS (from now legOS, for this post). I know (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | 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 (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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From the second scope screen capture here : (URL) you can see that the analog settling time is about 10 microseconds for the rotation sensor. Philo www.philohome.com (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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(...) I've found that any interrupt on the RCX has a minimum overhead of 101 to 113 states (or about 7 us). This is the time taken by the CPU to recognize and dispatch the interrupt plus the time the ROM routine takes to dispatch the interrupt to (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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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 (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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I did some "real world" tests with this update. I was Astounded at what a difference it makes. The bot I was testing with is a killough platform; which I had tried for hours previously, to get it to follow a line smoothly. I think BrickOS was giving (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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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 (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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| | Re: Interesting BrickOS Timing Results
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(...) 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 (...) (22 years ago, 15-Jan-03, to lugnet.robotics.rcx.legos)
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