Lpc2000

Yes that makes sense. I always initialize all my global variables in
main as a standard procedure (or some initialization procedure for
each module). That also includes all global variables as volatile and
if I need to save memory, I type cast all equation values to guarantee
that they are properly used or that I get a warning that there is some
compatibility problem by the compiler. Like in your case since the DC1
will always be below or equal to 100, then making that a char and then
type cast it in the equation as a (unsigned long).

regards,
Charles


--- In lpc2000@yahoogroups.com, "ed_hage" <ed_hage@y...> wrote:
> 
> I also posted the question on the gnuarm group and there I got a good
> tip. Apparently my startup code was not good; the globally defined
> variables were defined but not properly initialised. So I initialised
> it in main and then it worked!!
> 
> I try to get some info on startup-files, if anyone can point me in the
> good direction your ore than welcome (web-links, books etc.)  
> 
> Greetings, Edward
> 
> --- In lpc2000@yahoogroups.com, "charlesgrenz" <charles.grenz@s...>
wrote:
> > 
> > What's the assembly look like?
> > 
> > Charles
> > 
> > --- In lpc2000@yahoogroups.com, "ed_hage" <ed_hage@y...> wrote:
> > > 
> > > Thanks for the explanation.
> > > 
> > > I defined it as volatile and really it still does not work.
> > > --------------------------------------------------
> > > volatile unsigned long	DC0 = 10;
> > > 
> > > void IRQMotorOut (void)
> > > {
> > >   PWM_MR4 = (PWM_MR0 * DC0) / 100; 
> > >   PWM_MR6 = (PWM_MR0 * 80)  / 100; 
> > >   PWM_IR = PWM_RESET_MR0; //clear flag
> > >   PWM_TCR = (1<<1);
> > >   PWM_TCR = (1<<0); 
> > >   VICVectAddr = 0;
> > > }
> > > -------------------------------------------------
> > > MR6 works great, MR4 not. MR4 will work if I put DC0 =20 inside the
> > > function, but like this its hopeless.I run out of ideas of what it
> > > could be solved.
> > > 
> > > > 
> > > > When ever you use a global variable, you have to specify it as a
> > > > volatile to tell the compiler not to opitmize the variable out
> of the
> > > > equation when working with any ANSI C compiler.
> > > > 
> > > > Also by type casting the variable the same as the register you
> want to
> > > > use makes sure that the compiler is not going to do something
funky
> > > > when optimization is performed no matter what level.
> > > > 
> > > > regards,
> > > > Charles
> > > > 
> > > > --- In lpc2000@yahoogroups.com, capiman@t... wrote:
> > > > > The "volatile" is the thing, which makes it worth trying out...
> > > > >