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Subject: 
RE: Mindstorms SDK and IR communication
Newsgroups: 
lugnet.robotics
Date: 
Sat, 23 Apr 2005 22:29:14 GMT
Reply-To: 
<dickswan@sbcglobal^Spamless^.net>
Viewed: 
1061 times
  
Yes. I have a suggestion. Don't use Ghost. It's a performance pig.

Now for some realistic advice. Go into the "Lego USB Tower" control panel.
Change the timeouts to 0 for write, and 70 and 50 for read instead of "100
and 200". See if this gives you better performance. If this works reliably,
make them even shorter. I suspect you might be able to get to "70 and 20".
The first timeout is the time to wait for first reply byte and the second
parameter is time to wait for subsequent reply bytes. RCX is very efficient
once it starts replying and second and subsequent reply bytes arrive about 5
msec apart, but you need something longer because the USB interface is
polled on a 10 msec basis and you need to account for this and other OS
delays.

Let me know if this helps.

-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com]On Behalf Of
Richard Davis
Sent: Friday, April 22, 2005 3:57 PM
To: lugnet.robotics@lugnet.com
Subject: Mindstorms SDK and IR communication

I have a quick question to those that have used the Ghost API as part of the
Lego Mindstorms SDK.  The setup that I have is the following:  Mindstorms
SDK 2.5, IR tower, RCX 2.0.  At the moment I am using GhSetWaitMode and have
a callback method for the responses.

The question has to do with how long GhExecute takes to execute command
queues with this setup.  Assume that the queue being sent has just one get
value command in it.  It is taking GhExecute 110 to 150ms to do its job.
First of all, is that performance you would expect to see for round trip
communication with the RCX brick using IR?  When I append 3 commands into a
command queue, GhExecute takes 450ms or so to do its job, so there doesn't
seem to be much of a performance gain by batching commands in this way.
Does anybody have some insight into the operation of GhExecute or solutions
to speed up the IR communication speed?


Richard Davis



Message is in Reply To:
  Mindstorms SDK and IR communication
 
I have a quick question to those that have used the Ghost API as part of the Lego Mindstorms SDK. The setup that I have is the following: Mindstorms SDK 2.5, IR tower, RCX 2.0. At the moment I am using GhSetWaitMode and have a callback method for (...) (19 years ago, 22-Apr-05, to lugnet.robotics)

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