Lpc2000

Thanks, Richard.

So, if I understand correctly, if I don't clear the interrupts in my 
interrupt handler (or a new interrupt happens while at the handler) 
the handler will be called again as soon as I restore the CSPR 
register, which should happen at my final MOVS PC,LR?

I'm worried about inadvertently writing code that would miss 
interrupts. As I get from your explanation, that's easy to avoid.

Guille

--- In lpc2000@yahoogroups.com, Richard Duits <yahoo@r...> wrote:
>
> With everything that generates an interrupt, you have to clear the 
> interrupt by reading or writing to a register. For example with the 
UART 
> you clear a data ready interrupt by reading the data. If you cannot 
> clear the interrupt (for example a UART transmit holding register 
emty 
> while you have nothing to send), you disable it. If you do not 
clear or 
> disable the interrupt, the interrupt will be called again 
immidiately 
> after you return from it.
> 
> Level sensitive interrupts are active if the input pin is low (high 
if 
> INTPOLAR bit is set), edge sensitive interrupts become active on 
the 
> high to low transition (if INTPOLAR bit is clear) of the input pin. 
All 
> internal interrupts are level sensitive. External interrupts are 
cached 
> and converted to level senstive interrupt by the external interrupt 
> controller.
> 
> 
> 
> Guillermo Prandi wrote:
> 
> > Hi! I read every doc I've found and I couldn't get a detailed
> > description of the interrupt mechanism in the LPC2XXX. In 
particular,
> > I'm looking for the following:
> >
> > - What happens to interrupts while they're disabled? Do they
> > get "cached"? I mean, if I'm in the middle of processing a UART0
> > interrupt and UART1 receives a new character, I'd probably have 
the
> > interrupts disabled. Will I miss the interrupt?
> >
> > - Provided the interrupts get chached while disabled somehow... 
That
> > would mean that they will trigger as soon as they're enabled, 
isn't it?
> > I plan to keep interrupts disabled while processing other 
interrupts;
> > could that work?
> >
> > - What's the exact difference between edge and level triggered
> > interrupts?
> >
> > Thanks in advance
> >
> >
> >
> >
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