I figure I should announce that I did fix the problem.

The problem was that I was trying to just ! the bit and be
happy.  However, this doesn't seem to work bitwise or logically!

So I did this (Reader's digest condensed version):

#define RXNOTINV        //rx bit is not inverted

#ifdef RXNOTINV

#ifdef RXNOTINV
for(;;)
{
        while(RXD == 0) continue;
        //delay 1/2 a bit
        if(RXD == 0) continue;
        //get a byte of data
        //delay to start of stopbit
        return ~c
}
#else
for(;;)
{
        while(RXD == 1) continue;
        //delay 1/2 a bit
        if(RXD == 1) continue;
        //get a byte of data
        //delay to start of stopbit
        return c
}
#endif


Thanks,

Craig

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Dennis Plunkett
> Sent: May 5, 1999 10:14 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: Serial interface problem
>
>
> I think that the problem is in the code itself the function ! is a logical
> NOT and not bitwise.
> If you need to do bitwize then: -
>
>
> void main (void)
>
> void
> main (void)
> {
>  unsigend char i;
>  volatile unsigned char PORTVAL;
>
>         i =~PORTVAL;            //bits now inverted
> }
>
> Hope this helps, I am assuming that you're using C
>
>
> Dennis
>
>
>
>
> At 22:10 5/05/99 -0500, you wrote:
> >It's not clear if you mean the PIC doesnt work, or if your code no longer
> does.
> >Assuming the latter, I think you'll find that you need to invert
> your bits.
> >i.e.
> >the logic states are reversed without the max232.
> >
> >Paul
> >
> >At 06:02 PM 5/5/99 -0600, you wrote:
> >>I am puzzled why when I try to interface the
> >>transmit data line from an rs232 interface to
> >>a pic through a 10k resistor to RA1 why it
> >>ceases to operate.  On a scope, the levels are
> >>a nice 5-0.
> >>
> >>Works fine with a max232.  The only changes
> >>I've made are to replace the max232 chip
> >>with a 10k, and change my Rxdata define from
> >>RA1 to !RA1.
> >>
> >>I'm sure someone else has ran into this one.
> >>
> >>Craig
> >
> >Paul Davis
> >Sr. Systems Engineer
> >OEM, Carrier Sales, Healthcare
> >pdavis@nbase-xyplex.com
> >www.nbase-xyplex.com
> >184 Shuman Blvd., Suite 200
> >Naperville, IL. 60563
> >Phone: 630-717-2960 x 3072
> >FAX: 630-357-4237
> >
> >
>