Lpc2000

Thanks Guille for raising a valid point.

1/  The certification requirement is not mine but that of a client.

2/  If your system can tolerate spurious interrupts *and*, you *may* still 
need to consider my findings because:

a)  PL190 clearly states the VIC does not handle interrupts that exhibit 
transient behaviour;

b)  the VIC on LPC family of processors is based on PL190 design; and

c)  advice from ARM (engineer working on PL192 design) is that my report 
may not cover everything that happens (or can happen) between the VIC and 
ARM in relation to various spurious interrupt scenarios.

For these reasons, irrespective of whether or not your system can tolerate 
spurious interrupts, I advocate prevention of spurious interrupts.

3/  The solution I proposed is applicable if you wish to prevent spurious 
interrupts:

a)  there are may OS'es that panic (and restart) when a spurious interrupt 
occurs;

b)  handling spurious interrupts in many kernels (eg Linux) is OPTIONAL; and

You should not be surprised to find that your favourite OS that runs on 
your favourite PC panics on receiving a spurious interrupt.

If Brendan's root question is along the same lines, then I trust this also 
answers his question.

Kind regards,

Jaya


>Message: 24
>    Date: Thu, 23 Mar 2006 14:21:59 -0000
>    From: "Guillermo Prandi" <yahoo.messenger@...>
>Subject: Re: spurious interrupts on LPC
>
>I'd like to point out that apparently (correct me if I'm wrong!) Jaya
>is radically against system that tolerate any interrupts whose source
>is unidentifiable. Apparently his products must pass some
>certification process that rejects this situation. Brendan's proposal
>is a solution to the problem "how to get a system running using UART
>interrupts", and what Jaya is proposing is a solution to the
>problem "how to get a system running so you never get an interrupt
>whose source you can't identify". It is clear that Brendan doesn't
>think that interrupts from unidentifiable sources are not that much
>of a problem. Hence the misunderstanding (unless I just added a new
>degree of misunderstanding; if that is case, my apologies).
>
>Guille

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