Thread: Control-C, etc
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Old 14th Jun 2021, 4:12 am   #19
TonyDuell
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Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 4,279
Default Re: Control-C, etc

Some time back I worked on a Computest unit, I mentioned it here. One puzzle I had was that the reset key (which like other machines of a similar vintage provides a hardware reset to the processor) seemed to do nothing.

It turned out there's a bit of logic on the keyboard PCB includng a monostable with a period of a couple of seconds. You have to hold the reset key down until the monostable times out for there to be a reset. Release it before that and nothing happens. This struck me as a rather neat way to protect against accidentally hitting the reset key.
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