The MAX232 is simple and cheap. In fact, you can probably get a sample fom
MAXIM.

----------
> From: Rogerio Odriozola <Rogerio_Odriozola@TVAMTY.COM.MX>
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: RS-232 using PIC 16F84 or 12C509
> Date: Wednesday, May 06, 1998 3:02 PM
>
> You say you only want the PC to comunicate to the PIC. If you want level
> conversion (sort of) the smallest and cheapest is to go with the 1489. 14
> pin dip or soic and about 39 cents. No hassle with caps.
>
> Rogerio
>
>
>
>
>
> tbrisebois@FPMX.COM on 06/05/98 10:29:09 AM
>
> Please respond to PICLIST@MITVMA.MIT.EDU
>
> To:   PICLIST@MITVMA.MIT.EDU
> cc:    (bcc: Rogerio Odriozola/MTY/TVA/Dataflux)
> Subject:  Re: RS-232 using PIC 16F84 or 12C509
>
>
>
>
> You can use the MAX206 which is offered from Maxim which is an 24 pin
> SSOP which is very small and only about $2.00.
> > > I know this has been mentioned before, I looked at the archive and I
> don't
> > have lots of free time on my hands. All I need to know is what will it
> take
> > to communicate to a PIC with a PC. I just need to transmit signals to
the
> > PIC via PC. I DON'T need the PIC to talk to the PC. Do I need a rs-232
ic
> > or what?? I'm new to this and am not sure what it will take. Any advise
> and
> > suggestions would be apprecited!!!!
> >
> >
> > You can get there with just connecting the pic directly to the PC. If
you
> > do, the logic 1 in the pic output is a zero to the PC.
> > I've written bit-banger full duplex com for the '84. In my case, we
used
> a
> > buffer transistor, but it wasn't strictly needed.
> > If you want a little protection on the port pins, a 470 ohm resistor
> would
> > be a good idea.
> > Any solution that only sends +5 and ground is violating the spec, but
the
> > 1489 receivers (maybe the most popular 232 Rx chip
> > on the planet) only sense + and ground.  The '88 transmitter sends +/-V
> as
> > per spec.
> >
> > A maxim chip will get you there, but it's large, and expensive.
> >
> > The soft uart routines have been done to death, so I imagine you've got
> that
> > code already.
> >
> >
> Todd Brisebois
> Engineering
> Fitel-Photomatrix
> tbrisebois@fpmx.com   (613)228-9695  ext.229