Alt-BEAM Archive
Message #09733
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Wed, 2 Feb 2000 23:58:08 -0800
Subject: [alt-beam] Re: The 240 microcore - was Bicore question
Glad you like it.
Live bug/legs down. The 240 microcore layout is shown viewed form the top
with IC pin 1 marked for reference.
The "arrow" symbol is a conventional ground symbol. All pins with that
symbol should be connected to ground. The 1G and 2G pins are the tri-state
enable inputs for the 2 groups of 4 buffers which are active when the
corresponding enable pin is grounded.
Make sure you use the revised schematics since the original drawings showed
the diodes in backwards. The cathodes of the two diodes should be connected
to the two buffer outputs so that an active low output will neutralize the
secondary process and reset the saturated state of a microcore ie only one
process can be active in the microcore.
regards
wilf
> -----Original Message-----
> From: adam-m [SMTP:robotbreeder@telus.net]
> Sent: Wednesday, February 02, 2000 10:43 PM
> To: beam@sgiblab.sgi.com
> Subject: RE: The 240 microcore - was RE: Bicore question
>
> Incredible!
>
> Wilf, stupid newby questions: pins down or deadbug? Why the different
> grounds? (arrow) 1G, 2G ??
>
> Will try this soon!
>
>
> -----Original Message-----
> From: owner-beam@sgiblab.sgi.com [mailto:owner-beam@sgiblab.sgi.com]On
> Behalf Of Wilf Rigter
> Sent: Tuesday, February 01, 2000 7:46 PM
> To: 'beam@sgiblab.sgi.com'
> Subject: The 240 microcore - was RE: Bicore question
>
>
> And they said it couldn't be done!
>
> Here is a tested 74HC240 microcore (no not a bicore) circuit which behaves
> just like a 74HC14 type microcore and motor driver combined. I have bench
> tested the circuit with small lens motors and VCR ejector motors. Stalling
> the motors by hand produces a slightly shorter pulse duration but
> otherwise
> the circuit just keeps on ticking. The motion of the motors is the
> characteristic non-overlapping microcore sequence. The circuit is similar
> to the "quasi microcore" design I reported some time ago.
>
> The new 240 uCore circuit is similar to a microcore but uses normal HC240
> inverters instead of Schmitt triggers. Such a linear microcore circuit
> normally would not work but this problem is overcome by adding positive
> feedback from the non-inverted motor driver outputs using a capacitor.
> This
> positive feedback speeds up the transition through the linear region using
> what I call AC hysteresis. Assuming a switching threshold of 1/2Vdd, the
> ratio of C1/C2 must be greater than 2 and the time constant will be
> proportional to R*(C1+C2) since the bias point input voltage will clamp at
> Vdd on the positive edge of the input signal. Note the location of the C1
> caps, some of which are mounted between pins on the solder side of the
> chip.
> The two diodes (which can be any type 1N914/1N4448 etc) provide an
> automatic
> PNC function, far simpler and easier to use than the old Nu type PNC
> circuit. The layout of this circuit would appear to lend itself very well
> to
> freeforming. If possible, I will try to incorporate a reverser function
> to
> this circuit without adding (many) more parts unless someone beats me to
> it
> of course.
>
> enjoy
>
> wilf
> <<240UCOR1.gif>> <<240UCORE.gif>>
> > -----Original Message-----
> > From: Phillip A. Ryals [SMTP:phillip@ryals.com]
> > Sent: Sunday, January 30, 2000 9:21 AM
> > To: beam@sgiblab.sgi.com
> > Subject: Re: Bicore question
> >
> > > Ok I'm feed up with trying to make a Microcore walker.
> > > Ao I've turned to the bicore.
> >
> > Thanks what I'm screaming! I've made two m/s bicore walkers, and
> decided
> > to
> > go to the microcore. I thought it would act more along the lines of
> what
> > I
> > wanted it to do.
> >
> > I breadboard it, and it works fine. I solder it all together, and it
> > refuses to work. I've checked all my solder joints, and made sure
> > everything's touching where it should, but I still can't manage a
> working
> > model. All I'm left with now, is perhaps that I ruined the chip with
> > heat.
> > Are the 14's more sensitive than the 240's? I'm using one of those
> > universal PCB's, and I soldered all the pins of the 14 at once. Is that
> a
> > problem? I haven't had a problem doing it that way with 240's and
> 245's,
> > so
> > I figured I could get away with it.
> >
> > Any suggestions?
> >
> > -phillip
9734 Wednesday, 2 February 2000 11:24 Re: Nifty little bug program beam@sgiblab.sgi.com jester96beam@iname.com
>Ah yes. I downloaded this program a while ago. It's great, and very
addictive. I do wish the guy would finish it though, I've already beaten the
game several times.
>
>Anyone who hasn't tried this should do so. It's great fun (and almost BEAM
related, too :-)
>
>Chris
>
> ---- you wrote:
>> Hello there all!
>>
>> A lurking friend of mine sent me this link the other day. There you can
find a "game" called BUGBRAIN. Very cool neural programming sharware! I
love it and it helps with understanding how to make more complex Nv and Nu
networks.
>>
>> Check it out! Thanks to Sam (samn7)!
>>
>> Richard Caudle
>> www.geocities.com/frankendaddy
>> Home ICQ - Frankendaddy
>>
>> Guardians of the sacred words: Nee, Ptang, and NeeWhon!
>
>
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