INTRODUCTION TO MICROPEOCESSOR
MICROCOMPUTER SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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ICW1
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ICW2
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OCW1
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OCW2
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Detailed explanation-1: -8259 has four initialization command words namely ICW1, ICW2, ICW3, and ICW4 and three operation command words namely as OCW1, OCW2, and OCW3. The processor reads the status of 8259 by reading at the two ports termed as low port and the high port.
Detailed explanation-2: -8259 combines the multi interrupt input sources into a single interrupt output. Interfacing of single PIC provides 8 interrupts inputs from IR0-IR7. For example, Interfacing of 8085 and 8259 increases the interrupt handling capability of 8085 microprocessor from 5 to 8 interrupt levels.
Detailed explanation-3: -Initialization Command Word 2 (ICW2): This is used to load the high order byte of the interrupt vector address of all the interrupts.