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Oliver, > Did your experiments include tests for the probability > of corruption of different registers? In a word: no. I agree that this is an interesting issue. Most of what we have published so far has started from the assumption that PC/IP corruption happens. We have been mainly interested in dealing with the consequences. We have focused on PC/IP because corruption of this register has immediate (and potentially devastating) consequences in many applications. Using the same approach, we could (fairly easily) look at the impact of corruption to different registers. As you say, it's a question of time. Best wishes, Michael. ----- Original Message ----- From: "Oliver Betz" <> To: <> Sent: Friday, June 07, 2002 12:44 PM Subject: Re: [m68HC11] Watchdogs and safety (was Thinking...) > "Michael Pont" <> wrote: > > [you mentioned PC/IP corruption by EMI] > > > We've done some work on this, but none of it is specific to HC11. > > > > You'll find a copy of one of our papers: > > Thanks. One of the most interesting statements in this document is > this one: > > "The Instruction Pointer is only one of many registers in an embedded > processor and there is no evidence to suggest that this particular > register is any more or less susceptible to EMI than the others." > > Did your experiments include tests for the probability of corruption > of different registers? > > Although I don't _know_ the mechanism, I doubt that registers are > influenced directly. There is no direct connection between the outer > world and the register, therefore it's well protected. > > But the PC/IP has such a "connection": the clock input. I suspect > that illegal (e.g. too short) clock pulses can influence the PC/IP > logic. When I ran the HC12D60 with the PLL activated, there was no > more "code runaway". Well, that's no "evidence" but a suspicion. I > did not yet investigate the topic in detail. > > IMO it would be interesting: to > > - check the susceptibility of different registers > - look at the susceptibility of the clock input of the DUT > > to search for "evidence to suggest that this particular register is > any more or less susceptible to EMI than the others." > > At the moment I'm not able to do it, but maybe in the future. > > Oliver

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