AVR-Chat

Hi Jose,

No, the input signal was buffered with a 74HC244, so my highs were
high and my lows were 0. I did actually try enabling the pullup at one
stage, but it didnt make any difference. 

Further on, I started writing the code yesterday with 8M internal
oscillator just to start getting the code done, and it works fine on
PIND.0 

I checked the fuses in AVRSTUDIO and saw that CKOPT was not ticked .
.. (DOH) Havent tried changing it yet, but im sure it will work.

Thanks !

Hein B
Auckland, New Zealand.

--- In AVR-Chat@yahoogroups.com, Jose Fuentes <josecarlosfuentes@...>
wrote:
>
> Hein,
> did you enabled the PIND.0 pull-up?
> 
> Regards
> 
> Jose
> 
>  --- kernels_nz <hein@...> escribió:
> 
> > Hi Ivan -- MORE INFORMATION !
> > 
> > Nope, using PIND.0 as general input, in fact, the
> > plan is to use
> > PIND.0 as general input to detect the start
> > condition on a DMX512
> > packet and then change it to to UART RX to receive
> > the individual
> > packets after that.
> > 
> > What I have done so far is look for the start
> > condition (PIND.0 low
> > for more than 80us) and just toggle one of the
> > outputs everytime it
> > receives a start condition. Doing this on PIND.0 is
> > very erratic!
> > changing the code only in such a way that I check
> > any other pin, it
> > works perfectly.
> > 
> > Another thing worth mentioning . . . I have noticed
> > that PIND.0 is
> > also starting to load my input signal for no
> > apparent reason after a
> > while of operation. The input signal is buffered,
> > output swing is GND
> > to 5V. After a while of running with this signal
> > connected to PIND.0,
> > the output swing measured with my scope droops to
> > GND to approx 2.5V
> > 
> > Im starting to think more and more that the input
> > signal is affecting
> > the crystal clocking somehow, will try again tonite,
> > and seperate them
> >  as far as possible and also check the fuses etc. as
> > some of the other
> > guys suggested.
> > 
> > Thanks
> > Hein B
> > Auckland, New Zealand.
> > 
> > --- In AVR-Chat@yahoogroups.com, "Ivan Vernot"
> > <ivernot@> wrote:
> > >
> > > Hien,
> > > Just a thought.... PIND.0 is shared with RXD on a
> > mega16 - you don't
> > have 
> > > the UART enabled while you are trying to read
> > PIND.0? ;-)
> > > 
> > > HTH
> > > Ivan Vernot
> > > 
> > > 
> > > ----- Original Message ----- 
> > > From: "kernels_nz" <hein@>
> > > To: <AVR-Chat@yahoogroups.com>
> > > Sent: Tuesday, February 07, 2006 8:19 AM
> > > Subject: [AVR-Chat] Re: Problem reading PIND.0 on
> > Mega16 with 16MHz
> > Crystal
> > > 
> > > 
> > > > Hi Guys, Thanks for all the suggestions, will
> > check the fuses tonight
> > > > when I get home, I think the suggestion that the
> > input is actually
> > > > affecting the crystal instead of the other way
> > round sounds very
> > valid.
> > > >
> > > > Im only checking PIND.0 as general input, and im
> > reasonably
> > > > experienced with AVR's , so dont believe it's a
> > simple code problem.
> > > > As I said, using PIND.0 = dont work, any other
> > one of the PIND pins
> > > > works fine.
> > > >
> > > > THANKS AGAIN ! GREAT SUGGESTIONS FROM EVERYONE !
> > > >
> > > > Cheers
> > > > Hein B
> > > > Auckland, New Zealand.
> > > >
> > > > --- In AVR-Chat@yahoogroups.com, "Dave VanHorn"
> > <dvh@> wrote:
> > > >>
> > > >> > Could noise from the crystal pin be coupling
> > to the data input
> > > >> > and corrupting the data stream somehow ?
> > could this be happening
> > > >> > inside the Mega16 ? If so it is unfortunate
> > that Atmel have
> > placed the
> > > >> >  RXD pin of the UART right next to the
> > crystal pins.
> > > >>
> > > >> Far more likely that your input signal is
> > disturbing the crystal.
> > > >> If you haven't programmed the CKOPT fuse, then
> > do so.
> > > >>
> > > >> After that, see my other post on checking the
> > oscillator design.
> > > >>
> > > >> There are also possible layout issues,
> > involving how the crystal caps
> > > >> return to the AVR's ground pin. They should do
> > so on an isolated
> > track
> > > >> that connects to system ground only at the AVR
> > pin.
> > > >>
> > > >> > Unfortunately I really do need to use a 16MHz
> > crystal also, so
> > merely
> > > >> > ignoring the problem and using a slower
> > oscillator will not work !
> > > >>
> > > >> On a more mundane note, this may be a code
> > problem, can you
> > detail how
> > > >> it is that you're checking the pin?
> > > >>
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > 
> > 
> > 
> > 
> > 
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> >     AVR-Chat-unsubscribe@yahoogroups.com
> > 
> >  
> > 
> > 
> > 
> 
> 
> 
> 	
> 
> 
> 	
> 		
> ___________________________________________________________ 
> 1GB gratis, Antivirus y Antispam 
> Correo Yahoo!, el mejor correo web del mundo 
> http://correo.yahoo.com.ar
>