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4652 Sat, 19 Jun 1999 08:36:11 -0500 [alt-beam] Re: 245 driver / reverser in 1 chip beam@sgiblab.sgi.com Todd Cottle Received game. Left positive feedback. Thanks -- Todd
Sean Rigter wrote:
> Actually I haven't seen it before but won't work as described. It needs
> a two (10K) resistors from each 74HC14 output in series with each 245
> connection. The problem is the active output of the 245 must be isolated
> from the 74HC14 output because the 245 is a buffer and the 14 output is
> not "strong" enough to change logic levels. The resistors do the job.
> However a 240 can do the same thing without the resistors and my own
> AC157 or AC257 reverser (from many moons ago) does a nice job of
> reversing motors too with a smaller package, less wiring and higher
> output current.
>
> wilf
>
> "van Zoelen, Bram SSI-TSEA-352" wrote:
> >
> > Isn't this in the FAQ already?
> > I think soo.
> >
> > Bram
> >
> > > ----------
> > > From: Ben[SMTP:mesiti@pbq.com.au]
> > > Reply To: beam@sgiblab.sgi.com
> > > Sent: Tuesday, April 20, 1999 12:07 PM
> > > To: mailing list
> > > Subject: 245 driver / reverser in 1 chip
> > >
> > > <>
> > > Here's a circuit I designed that uses the direction pin on a 245 to swap
> > > the
> > > polarity of the rear motor on a two motor walker. I'm pretty sure it will
> > > work, but I haven't built it yet. Basically, for the rfront motor, the
> > > driver is normal. One driver for each of the poles on the motor. But it
> > > uses
> > > another two, who's outputs have the microcore output on them as well, and
> > > the inputs of these gates got to the motor, so when the chip reverses the
> > > front motor remains in the sam direction. For the fron motor however, 2
> > > outputs from the microcore go to the input of one gate, and the output of
> > > another gate. The outputs and inputs of these gates respectively go to the
> > > motor, however unlike with the front motor, the rear motor's second set of
> > > drivers is reversed (the ones coming from the "inputs" of the second set
> > > of
> > > drivers); so when the chip's direction pin is enable (from a reverser
> > > sensor
> > > etc), the drivers reverse direction and the rear motor's polarity changes,
> > > Making the walker go backwards.
> > >
> > >
> > > Any comments? What do you guys (and girls) think??
> > >
> > >
> > >
> > >
> > > __________________________________________________________________________
> > > __
> > > I really need to come up with a good saying.....
> > > ICQ#24602841
> > > http://www.geocities.com/TimesSquare/Cavern/9282/
> > >
> > >
> > >
>
> --
> Hey, come visit my homepage at
> http://www.geocities.com/Area51/Nebula/1710/
> Southpark, Mechwarrior2, V&V, Al-Qadim, and Milla Jovovich!
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