ok thanks a lot guys.


Russ.


> -----Original Message-----
> From: M. Adam Davis [mailto:adavis@UBASICS.COM]
> Sent: Tuesday, July 11, 2000 1:46 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: 16F84 Serial question
>
>
> The RS-232 spec indicates that between -3v and 3v is no man's
> land for a valid
> RS-232 signal.  3-12v and -3 to -12v are ok.
>
> However, the vast majority of hardware UARTs produced now let
> 0v (gnd) fall into
> the -3v to -12v range.  Thus the effective range of most
> RS-232 receivers is -12
> to 1v and 3v to 12v.  So 0v and 5v are valid signals.
>
> You will commonly see hobbyist circuitry which drives the
> recv line of RS-232
> directly from the micro, and accepts the TX line of the
> RS-232 port through a
> resister (and clamping diode) directly to a pin on the micro.
>  Since the PIC has
> internal clamping diodes you will run across RS-232 PIC
> interfaces that use only
> one resister.
>
> -Adam
>
> Russell Farnhill wrote:
> >
> > Hi,
> >
> > I've Been playing around with some serial routines on a F84.
> >
> > With the PC serial RX pin connected direct to the TX pin on the PIC
> > I can seemingly reliably receive serial data using Hyper Terminal.
> >
> > I thought that a MAX232 chip or similar was needed to send
> 5v serial data
> > to a PC. Is this just a fluke or am I missing something here ?
> >
> > Thanks,
> >
> > Russ.
> >
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