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Subject: 
Re: NXTway DS powered by LEJOS OSEK
Newsgroups: 
lugnet.robotics
Date: 
Fri, 10 Aug 2007 10:34:10 GMT
Viewed: 
4374 times
  
Could you try the no-so-optimized version (which does 15 useless
display updates) and see how fast that is?  I'll post both versions,
because what you've done is a very good example.

Steve

I could measure the performance for the three cases and it was also very
interesting for me.

#no-so-optimized(update LCD every time)
Loop count: 2695 (very slow)
Size: 18240byte(includes LEJOS OSEK firmware)

#optimized(LCD is updated every 16msec)
Loop count: 334k
Size: 18144byte(includes LEJOS OSEK firmware)

#no Display (only at the last time)
Loop count: 1825k (thanks GCC)
Size: 18128byte(includes LEJOS OSEK firmware)

For LEJOS OSEK, LCD update is a critical bottle neck. I think this is caused
by using software polling for spi interface. If I could use an interrupt,
the performance should be much better. (but, haven't confirmed yet, so this is
just a guess). I do not say any execuse, if somebody wants to use LEJOS OSEK
for drawing something (graphics) on the LCD, I would not recommend it so far.

Thanks,
Takashi



Message has 1 Reply:
  Re: NXTway DS powered by LEJOS OSEK
 
Hi Takashi, (...) you can use interrupts and the PCD (DMA-channel), so it should be possible to do it with a very light load on the processor. Jürgen (17 years ago, 10-Aug-07, to lugnet.robotics)

Message is in Reply To:
  Re: NXTway DS powered by LEJOS OSEK
 
(...) Thanks. I'm just glad to see people are having fun with it. (...) This is actually a bit tricky. Dick Swan (RobotC) asked about optimizing the display update function like you've done (for the same reason you did it). Basically, it means this (...) (17 years ago, 6-Aug-07, to lugnet.robotics)

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