Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: [ANNOUNCE] New PC-Speaker driver | Date | Thu, 15 Aug 2002 13:28:03 +0200 |
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On Thursday 15 August 2002 12:57, Alan Cox wrote: > There are easier equivalent ways to accurately measure the IRQ > behaviour. Flip the state of a parallel port pin when you mask > interrupts. You can even slap an oscilloscope on it that way
Right, I'll just go get my oscilloscope now...
In fact I relied on the technique you mentioned a great deal when I was doing realtime work with PCs. With a multi-trace digital scope the effect is something like a poor-man's logic analyser with a resolution of 10 us or so.
Another technique I can recommend highly is panicking by halting in a tight loop with the speaker set to emit some tone. It may be annoying for the guy at the next bench but in some code, such as transitioning to/from virtual86 mode, there aren't a lot of alternatives.
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