I tried debugging RCREG directly as a last resort.  Previously, I had been
moving the value out to another register first; thus, one read per
character.  However, the results are the same either way.

Jen

> -----Original Message-----
> From: Peter Onion [mailto:ponion@srd.bt.co.uk]
> Sent: Thursday, January 24, 2002 11:43 AM
> To: pic microcontroller discussion list; pic microcontroller
> discussion
> list; Jennifer Loiacono
> Subject: RE: [PIC]: PIC18 USART RX Data Corruption
>
>
>
> On 23-Jan-02 Jennifer Loiacono wrote:
> > Jennifer Loiacono
> > President
> > Automaton Engineering, Inc.
> > P.O. Box 10282
> > Brooksville, FL 34603When receiving serial data on the
> PIC18C442, the value
> > is not reflected correctly in the RCREG reception register.
>  However, the
> > signal on the receiving PIC is perfect in terms of timing
> and accuracy.
> > Despite accurate signal levels, debugging RCREG immediately
> after data is
> > received reveals that the byte seems to flip back and forth.
> >
> > e.g., a byte equal to 4 (dec) will oscillate between 4 and
> 32.  A byte equal
> > to 1 will oscillate between 1 and 128, etc.
>
> I'm not quite clear on what you mean by " oscillate between 1
> and 128".
>
> If I've missunderstood then please ignore me, but it sounds
> to me that you
> reading the RCREG multiple times for each recieved character ?
>
> I'm pretty sure that isn't allowed by the PIC.  You should read RCREG
> ONCE and ONLY ONCE for each recieved character.
>
> RCREG should be read ONCE each time the RCIF bit in PIR1 is
> set. Reading RCREG
> will reset this bit automagically ready for the next character.
>
> Peter Onion.
>

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