Hi, For a real time embedded system, is there any requirement on the processor architecture to meet the real time requirement? Does realtime system depend on realtime OS to meet the realtime requirement?
Thanks Jogging
Yes. The CPU must be in stock at Digikey, otherwise the realtime could be problematic.
Looks like your professor gives you a hard realtime.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
On Thu, 6 Mar 2008 17:35:43 -0800 (PST), snipped-for-privacy@gmail.com wrote in comp.arch.embedded:
What is "the real time requirement"? I did not know that there was only one. Every real time system I have worked on so far, and there have been a lot of them, have had their own different requirements.
Now that we've straightened that out, yes, just about every real time system usually impose some minimum performance requirements on the processor/controller/DSP.
The requirements of some real time systems can be met by an original
8051 running at 12 MHz. The requirements require much more powerful processors.Some do, some don't.
-- Jack Klein Home: http://JK-Technology.Com FAQs for comp.lang.c http://c-faq.com/ comp.lang.c++ http://www.parashift.com/c++-faq-lite/alt.comp.lang.learn.c-c++ http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html
"Real time" is pretty much accepted to mean that if an event happens, and your system doesn't respond to it quick enough, then the system isn't meeting spec. Some folks separate this into "hard real time" which means that if even one deadline is missed by even one nanosecond then disaster strikes, and "soft real time" which means that some deadlines can be missed, with some sort of graceful failure that gives degraded performance long before things crash and burn.
So the only requirement on a processor architecture to be suitable for _some_ real time application is that it be deterministic, that is that you can always calculate the maximum possible time for the processor to carry out a given task. Once you've established that, then you can determine if it'll be fast enough to meet _your_ particular real-time requirement.
In general, no, although for large complex systems a real time OS can make the development easier. (note that a real time OS also makes the development more complex and the problems more obscure -- developers of really critical applications tend to shy away from RTOS's for this reason).
Regardless of what framework you're doing it in, real-time software development requires that you pay attention to details from one end to the other. It's not the right place to jump in and play without knowing what you're doing.
-- Tim Wescott Control systems and communications consulting http://www.wescottdesign.com Need to learn how to apply control theory in your embedded system? "Applied Control Theory for Embedded Systems" by Tim Wescott Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.