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 Robotics / RCX / legOS / *2289 (-20)
  RFC: Creation of Version 0.2.6
 
I think it would be a very good idea to incorporate the prio-patch to legOS. But there seem to be a lot of patches and enhancements for 0.2.5. Personally, I use the remote control patch from Zhenrong Zang. And there is the TCP/IP system... Any more (...) (23 years ago, 9-Feb-02, to lugnet.robotics.rcx.legos)
 
  Priority Interrupt Patch and legOS-0.2.5
 
We are gathered here to witness the union of priointerrupt-patch.diff and legOS-0.2.5. If anyone has just cause why these two should not be wed may they speak now or forever hold their peace. Robert Templeton (23 years ago, 8-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
Still no luck in getting the mux working properly. I tried making use of the code for turning sensors on and off but later realized that the ds_handler code would still be turning the sensor off as part of its normal operation. I think I'm going to (...) (23 years ago, 7-Feb-02, to lugnet.robotics.rcx.legos)
 
  Real time operating system resources
 
Now that my interest has been piqued by the multiplexer problem (and sensing problem in general), what would some of you hardened embedded/real-time system veterans recommend for reading on the subject. Two books that I've found at Amazon.com are (...) (23 years ago, 6-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) I'm just checking this thing out. You can look at: (URL) more information. Unfortunately, I got the .ps description file but not the source code patch file. A mail asking for it is on it's way ;) Mike (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) Actually, something like this has been documented and done by Pedersen, Christensen, Rasmussen ("Prioritized Interrupts in LegOS"). They actually document the problem of sensor misses related to task management, significantly reducing the (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) Most people's legOS kernels will be compiled so msleep uses wait_event. I haven't looked at the code, but my understanding of how wait_event works is that whenever that thread becomes eligible to execute, your even function is called. (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
Try the following code fragments. [Change to fixed spacing font so that it reads easily.] You should be able to find what you need. "Mark Falco" <> wrote in message news:Gr1MBL.Dop@lugnet.com... (...) <<..snip..>> (...) These are code fragment for (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
Ok, my last port didn't make much sense let me try that again. for an active sensor ds_handler will periodically power the sensor off to read the value. The standard firmware does this to but at a different interval. I'm wondering if this is part of (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
Since I'm now fairly sure that i've got the timing taken care of I'm wondering if the power cycling that ds_handler does is somehow causing the problem? I thought I might take control of this stuff in my test code. I assume if I set the sensor for (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) It looks like the semaphore task_sm should prevent another task from being scheduled if I hold it for the length of the train. I've now tried this as well as incresing the timeslice to 100ms. It looks better but still is not consistent. Since (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) Not bad. But as you say, still vulnerable to the task switching problem. (...) Instead of resorting to that, maybe there is a way to freeze task switching during critical operations. When I owned and programmed the AmigaOS (don't laugh :), (...) (23 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
#include <sys/time.h> void systime_set_timeslice (unsigned char slice); include/sys/time.h:43-45: #ifdef CONF_TM #define TM_DEFAULT_SLICE 20 file://!< default multitasking timeslice #endif hope that helps, Albert "Michael J Ash" (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) I agree about the cause for the msleep granularity, I'd seen the same stuff in tm and assumed that would cause the problem. Sorry my last note was a little unclear, I tried msleep and delay but am now using my own function which seems to (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) I don't know about this 20ms granularity and how delay() is going to be any better. Here's the code for each function: //! delay execution allowing other tasks to run. /*! \param msec sleep duration in milliseconds \return number of (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) Thanks, I'd suspected that msleep might not be very accurate but never considered that it's true granularity could be so large. I did a quick test with my current configuration and when I asked msleep to sleep for 12ms it slept for 20. This (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: true tcp/ip on the RCX
 
(...) The C64 server survived the "Slashdot attack" without problems, even though it served tenths of thousands of pages over a period of only a few hours. Since it is configured to allow only 10 simultaneous connections, it could more or less serve (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
(...) Don't ask me for a cite, but I seem to remember something about msleep only having 20ms granularity. If that's the case, your msleep(10) is either not sleeping at all or is sleeping 20ms, either one of which could cause problems. I'd suggest (...) (23 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
 
  Re: multiplexor and legOS
 
well anyone who looked at the code I attached may have notcied that I had one of the msleeps commented out. Oops, with this now uncommented I at least see the second and third light sensors pulse on, but only for an extremely short time. Suring the (...) (23 years ago, 3-Feb-02, to lugnet.robotics.rcx.legos)
 
  multiplexor and legOS
 
Does anyone have expierence using the active multiplexor sold by www.mindsensors.com with legOS? If you are not farmiluar with this multiplexor it is really cool as it lets you multiplex three active sensors on one port. You tell the mux which "sub" (...) (23 years ago, 2-Feb-02, to lugnet.robotics.rcx.legos)


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