Timer (Computer "tic")The Timer is located in the Interrupt Controller. It is a simple counter triggered from the System Clock and wired to produce interrupts at long intervals (for example, 1 ms) set by DIP switches.
The address for the Timer Service routine is indicated in memory location 0x0000. When the timer interrupts, the Interrupt Controller loads the Program Counter (PC) with the content of that memory location (after have saved PC and F to the Stack).
This interrupt is not affected by the DI instruction but it can be disabled from the Console.
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Homebuilt CPUs WebRing
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Join the ring?
David Brooks, the designer of the Simplex-III homebrew computer, has founded the Homebuilt CPUs Web Ring. To join, drop David a line, mentioning your page's URL. He will then add it to the list.
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Project start date: May 13 of 2009
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