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* [Xenomai-core] Analogy DIO speed
@ 2010-02-17 21:23 Stefan Schaal
  2010-02-18 22:34 ` Alexis Berlemont
  0 siblings, 1 reply; 10+ messages in thread
From: Stefan Schaal @ 2010-02-17 21:23 UTC (permalink / raw)
  To: xenomai; +Cc: Peter Pastor Sampedro

Thanks to Alexis's Analogy development, digital I/O is possible with Xenomai using National Instrument DAQs. While the basic DIO functionality works in the most current xenomai-head, I am  wondering how to achieve maximal I/O speed with the 32 bit digital I/O sub-device on my NI6259 card. 

The options are

1) single acquisition with a4l_sync_dio()
2) instructions and instruction lists using a4l_snd_insnlist() and a4l_snd_insn()
3) streaming acquisition with commands (e.g., a4l_snd_command() and related functions)

My question concerns how many 32-bit DIO instructions per second I
should be able to achieve with the various options.

For instance, option 1) seems to take about 5000 nanoseconds on my
Ubuntu 8 core i386 computer (3Ghz processors).
Is this normal? Or should it be faster?

Option 2) seems to give me about 50% speed up, i.e., roughly 3500
nanoseconds per DIO.

Would option 3) give me a massive speed up and get me closer to the
20Mhz processing power of the NI 6259 board? I have some problems with 
implementing commands on my NI6259 so far.

Thanks a lot for any help!

-Stefan


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2010-03-04  8:37 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-02-17 21:23 [Xenomai-core] Analogy DIO speed Stefan Schaal
2010-02-18 22:34 ` Alexis Berlemont
2010-02-18 22:48   ` Thomas Lockhart
2010-02-19  5:43   ` Stefan Schaal
2010-02-23 23:22     ` Alexis Berlemont
2010-03-01  0:24       ` Alexis Berlemont
2010-03-02 18:00         ` Stefan Schaal
2010-03-03 23:58           ` Alexis Berlemont
2010-03-04  0:54             ` Stefan Schaal
2010-03-04  8:37               ` Alexis Berlemont

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