On Wed, 17 Feb 2010, ivp wrote:

> Cristiano,
> 
> > I have got the feeling it is not good spending most of the CPU time
> > handling interrupt routines
> 
> Where the PIC is spending its time is largely irrelevant. An interrupt is
> just another routine

If you look at just the one interrupt - maybe. But if you're getting a 
mess of them happening all the time - definately not!!!

The amount of time the CPU spends executing a regularly occuring interrupt 
routine can have a dramatic effect on the main line code. E.g. if you have 
an interrupt occuring every 2ms and the interrupt routine takes 1ms to 
execute then your main line code will effectively see a decrease in speed 
of 50%.

If you're not doing anything in the main line then everything is fine but 
if you need to do any kind of real work in the main line then you 
shouldn't be sloppy about your interrupt handler.

Friendly Regards
Sergio Masci
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