Actually, I am using an external temperature compensated crystal
oscillator. It provides a 0 to 5 volts square wave to pin 13 at "precisely"
5 MHz (give about 1 part in 10^8 or so). I have tried using HS oscillator,
XT oscillator, and RC oscillator. I get a nice square wave on pin 14 with
the RC oscillator selected, at, if I recall, 1/4 the basic clock frequency,
but generally I have been using HS oscillator setting, since that is what I
was told to do by Microchip, although that results in a 5 MHz messy
triangular waveform on pin 14.

Ed

At 04:46 PM 8/7/2001 -0500, you wrote:
>Maybe I'm coming in late on this one, but...
>
>Is your oscillator oscillating?  Can I safely assume you've tried a
>different (lower frequency maybe even) xtal?  It *is* a parallel resonant
>xtal and not series resonant, right?
>
>Dale
>
>On Tue, 7 Aug 2001, Ed Troy wrote:
>
> > Incredible!! Even this does not work. I am doing something incredibly
> > stupid, but I can't figure out what it is. Either that, or my programmer (a
> > Topmax) is totally bad, and saying that it is programming chips, and
> > verifying them, but not, and I can't believe that. Basically, I am now
> > using a 16F874 chip, because it is quick and easy to erase, and I cannot
> > get any code to work, although everything I try works fine in the
> > simulator. Also, I have noticed that in spite of putting in a line
> > TRISD=0x00, (or TRIS whatever), all ports appear to be tristated and
> > sitting at 0, since a 10k pullup resistor easily pulls them to high. The
> > only ports on my device that are at 1 are RD0 and RD1, because they are
> > pulled up by external pullups. (But, nothing I do can get them to 0.)
> >
> > At this point, I am suspecting some strange hardware or programmer problem.
> > Does anyone have a simple (even as simple as the code attached below), that
> > is compiled for a 16F874. All I need is the hex file, and a brief
> > explanation of what it does, as long as the hex file is known to work on
> > actual hardware? Then, I could load that into one of my devices and see
> > what it does on the actual board.
> >
> > TIA,
> > Ed
> > At 11:35 AM 8/6/2001 -0700, you wrote:
> > >>I have corrected the typo, although that would not have stopped something
> > >>from toggling. I checked my circuit, and it is basically the same as
> yours.
> > >>The only difference is that I hardwired ~MCLR to +5 volts. The rise
> time is
> > >
> > >
> > >etc.
> > >
> > >I can only offer a few more suggestions:
> > >
> > >1) Use an even simpler program for the test. e.g.
> > >
> > >main() {
> > >     TRISD = 0x00;
> > >     PORTD = 0x55;
> > >here:
> > >     goto here;
> > >}
> > >
> > >No matter what else is going on in the system, PORTD should get stuck
> > >at 0x55, and resets won't affect that.
> > >
> > >2) Are you sure you're building the application for the 1674B? It
> > >might be for another chip ...
> > >
> > >Regards,
> > >
> > >--
> > >
> > >  ______________________________________
> > >   Andrew E. Kalman, Ph.D.   aek@pumpkininc.com
> > >
> > >--
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