There's alot of ways to do what you want, but I've been playing with
a Voltage-output 8-bit digital-to-analog converter "AD558" from
Analog Devices. You can find the specs at;
http://products.analog.com/products/info.asp?product=AD558
This is a parallel control input or you can use a "serial to parallel"
shifter from the pick and not tie up so many ports.
This chip can output either 0-2.56 +vdc or 0-10 +vdc with 8 bit
resolution. It works great or you can use PWM, if you don't need
the pic to do much more than that.



> It is not critical at all.  I just want to be able to control the speed of
> a motor like slow medium or fast.
>
>
> Andrew
>
> On Fri, 17 Mar 2000 12:06:17 -0600 Scott Dattalo <scott@DATTALO.COM>
> writes:
> > On Fri, 17 Mar 2000, Andrew Kelley wrote:
> >
> > > Does anyone know how to make an analog voltage/signal with an f84?
> >
> >
> > This will make a DC signal on the lsb of porta:
> >
> >   bsf  porta,0
> >
> > as will this:
> >
> >   bcf  porta,0
> >
> > A "strategic" combination of these can be concatenated to produce a
> > waveform whose average value can be used to produce an analog voltage.
> >
> > Or as we prefer to say on the list every few days: PWM. Here's a
> > software pwm
> > that works on the f84:
> >
> > http://www.dattalo.com/technical/software/pic/pwm256.txt
> >
> >
> > But it's probably overkill for what you want to do. But, OTOH, I
> > have no idea
> > what you exactly want...
>
> ________________________________________________________________
> YOU'RE PAYING TOO MUCH FOR THE INTERNET!
> Juno now offers FREE Internet Access!
> Try it today - there's no risk!  For your FREE software, visit:
> http://dl.www.juno.com/get/tagj.
>
>