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 Robotics / RCX / NQC / 1137
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Subject: 
NQC vs Spirit communication speed
Newsgroups: 
lugnet.robotics.rcx.nqc
Date: 
Fri, 11 May 2001 16:19:17 GMT
Viewed: 
2051 times
  
This is more a general RCX communication question, actually.  As I mentioned
here previously, I've ported the NQC communication code to Delphi for the
purposes of modifying RcxCC to not use the Spirit OCX.

At present I have a version of RcxCC that does everything the original
version does without ever using Spirit.  It uses my "FakeSpirit" class that
uses my port of the NQC RCX_Link, RCX_Cmd, and Serial code.  I'm relatively
satisfied with the results.  But there is a slight problem.

The original RcxCC (which uses Spirit) appears to communicate with the brick
much faster than my modified RcxCC does.  Polling for information using my
Spirit replacement is much slower than doing so via Spirit.  I've profiled
the application and the vast majority of the time is spent in the serial
class' read method.  It appears to retry a lot - almost always (if not
always) failing on the first send.  But Spirit somehow seems to do the exact
same operations in virtually no time at all.

Can anyone shed some light on this matter?

Thanks in advance for your help,

John Hansen



Message has 2 Replies:
  Re: NQC vs Spirit communication speed
 
The retry timing for RCX_Link uses a dynamic backoff, which is a good general purpose solution if you're going to be sending lots of packets (like a typical NQC download) and the latency through the serial driver is unknown and/or unpredictable (...) (23 years ago, 11-May-01, to lugnet.robotics.rcx.nqc)
  Re: NQC vs Spirit communication speed
 
hi John, I'm curious to see your "Fakespirit" class. At this moment I only need a limit set of commands, so I send by a couple of simple routines to my serial commport driver (indepent thread). Here is the basic code I use, timing is very a stable (...) (23 years ago, 11-May-01, to lugnet.robotics.rcx.nqc)

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