Jonathan A. Titus

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Lesson 10: Interfacing and Interrupts

From the original article in Radio-Electronics
by Jonathan A. Titus
The Mark-8 Minicomputer may be used with the TV-Typewriter to display computer generated information. The interface uses either the A or B Output Port strapped to the specific output code, 1-7, that you select. The A and B output ports have strobe lines which are pulsed during the output cycle. These two lines are found above the B output lines and below the A output lines on the printed circuit board. These strobe lines provide us with the Keypressed signal required to enter data into the TV Typewriter. A monostable is attached to this strobe line to stretch the pulse width and the 10 mF capacitor used for debouncing IS removed from the TV-Typewriter.
Read More: Adobe Acrobat PDF FileMark-8 Construction.pdf, p.5 [2.54 MB]

The INTERRUPT is used to do just that to the computer. We can interrupt the present program and cause the computer to temporarily do some other task and then return to the program . It is also possible to make the computer leave a stopped state with the interrupt.
Read More: Adobe Acrobat PDF FileMark-8 Construction.pdf, p.7 [2.54 MB]