Subject:
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Re: multi-device output controller (fwd)
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 26 Mar 1999 16:06:13 GMT
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Original-From:
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Jim Choate <RAVAGE@EINSTEINspamless.SSZ.COM>
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Viewed:
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951 times
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----- Forwarded message from Dennis Clark -----
From: "Dennis Clark" <dlc@verinet.com>
Subject: Re: multi-device output controller (fwd)
Date: Fri, 26 Mar 1999 15:27:53 GMT
Ha! I'm one up on ya both. Run a tight loop and find out how fast the
RCX can cycle the motors on and off, time it, and send a package a serial
message at whatever the fastest BAUD rate is to control a max of N motors
with X power settings either forward or reverse, or to keep the word size
small and still be useful, 4 motors (2 bits),forward/reverse (1 bit), 8
speeds (3 bits). You still have the two directly controlled motors which
means that you now have six fully controlled motors. Hmmm, if you can
spit the data out fast enough to avoid time slicing errors this just might
work!
----- End of forwarded message from Dennis Clark -----
What's the clock speed for the RCX and how many cycles does a read, write,
read take? I've only had mine 3 weeks, normaly I use a 8031 for my
robot and Lego stuff.
Why did you capitalize BAUD? It's not an acronym. The baud rate is the PRR
while the actual bit rate is 8 times that if we're going to take each
output and driving an 8-bit A/D with it. Since it's convenient to send the
data serial (in most cases) that's the rate we should be concerned with. If
we're working strictly parallel then PRR and bit rate are equivalent.
And your numbers are off:
4 motors 2 bits
for/rev/stop 2 bits
8 speeds 3 bits
The beauty of the mechanism I described previously is that you can use the
64 addresses for anything, not just controlling motors. You could bank
switch the inputs, control other hardware, etc.
What I had in mind was to take two outputs and integrate the signal with the
PRR (Pulse Repetition Rate) since it's fixed. Then the output of the
integrator is linked to a S&H (Sample & Hold) so that it can be A/D'ed. This
provides a dual channel parallel digital address buss. Do the same thing on
the 3rd output only use it as the data buss. Then any device that wants to
sit on the buss would have 2 8-bit addresses and a 8-bit data port. This
could be extended by using the inputs on the RCX as a mechanism to read the
data for each of those addresses as well.
____________________________________________________________________
The trouble with acting according to your conscience is that
once you start doing it, nobody can trust you any more.
Alexis A. Gilliland
The Armadillo Group ,::////;::-. James Choate
Austin, Tx /:'///// ``::>/|/ ravage@ssz.com
www.ssz.com .', |||| `/( e\ 512-451-7087
-====~~mm-'`-```-mm --'-
--------------------------------------------------------------------
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 1 Reply:
 | | Re: multi-device output controller (fwd)
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| (...) [snip] (...) Dunno, I haven't looked yet, I just came up with the idea. (...) Because I felt like it? I've seen it written both ways. [snip] (...) Nope. 0 (speed) means off, no matter what direction you are going, therefore: 0= forward, (...) (26 years ago, 26-Mar-99, to lugnet.robotics)
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