How fast ???
Since the Propeller has no hardware interupt, how fast can it react to a state change on a pin in software ???
I guess all traditional hardware interupts will have to be written in software now...
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
I guess all traditional hardware interupts will have to be written in software now...
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
Comments
I believe you are missing the point of the multiple cogs. Consider this- in a 'traditional hardware' setup (as you call it)- an interrupt is only as fast as a pin changing states as well as all of the necessary housekeeping to have the interrupt run/process- (this can vary depending on the hardware you are using)- So it naturally follows that a cog dedicated to a function will be able to react more quickly than an interrupt driven system...
Now all 'traditional hardware interrupts' should not have to be written in software now, if you don't stick to the paradigms imposed by a single processor system to this new, multiprocessor setup. The way to structure/approach your code should evolve to match and take advantage of the hardware you are working on.
Ryan
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Ryan Clarke
Parallax Tech Support
RClarke@Parallax.com
Then it'll continue execution within a few clock cycles.
The same commands exist in Spin also, but there it will take a few hundred clock cycles for the program to begin reacting a doing something. (It takes about 200 Assembly instructions to execute one Spin token by the interpreter)
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Don't visit my new website...
So if the COG is dedicated to waiting for a pin to go hign and I'm running a assembler code,
how fast will it start my code ???
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
In other words, the program will continue executing on the next clock cycle, and THAT is just as quick as any Hardware interrupt I've seen...
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How long is a clock cycle at 80MHz ???
I'm getting exited about this...
I would like to build my own Electronic Fuel Injection controller for my motorcycle.
Timing is very critical for TDC (Piston Top dead center), Fuel injector firing duration and timimg, and ignition timing.
This is all coming together for me now...
Thank you.
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
And that again means that most assembly-language instructions execute in 50nS, and that you can execute up to 20instructions in ONE uS.
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My testing reveals that at 80MHz, the "wait instruction" completes in 3 clocks (3*12.5 nSec) after the "proceed event", and the next instruction is started right after the wait instruction is finished. So that is 37.5 nSec after the "wait" is satisfied. Each instruction takes 4*12.5 = 50 nSec.
Cheers,
Peter (pjv)
Post Edited (pjv) : 5/12/2006 8:57:15 PM GMT
That·will provide plenty of acuracy ;-)
Way more that needed with today's Injector and Ignition technology.
The required precition·for a fuel injector is 1-1.5ms
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
I am currently working on a similar project (ECM for a BMW), and the Propeller fullfils all of the requirements.
Good luck with your project!
(Go for it!)
Have you seen this: http://www.megasquirt.info/
This is where I'm gettign my ideas and a lot of knowledge from.
It will take me a while as well· ;-)
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Ibsen
" It's nice to be important, but
·· more important to be nice... "
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Chris Savage
Parallax Tech Support
csavage@parallax.com