Question

Once the ICW1 is loaded, then the initialization procedure involves

(a) edge sense circuit is reset

(b) IMR is cleared

(c) slave mode address is set to 7

(d) all of the mentioned

This question was addressed to me in semester exam.

My doubt is from Programmable Interrupt Controller 8259A in section Special Purpose Programmable Peripheral devices and their Interfacing of Microprocessor

Answer 1

Right option is (d) all of the mentioned

Explanation: The initialization procedure involves

i) edge sense circuit is reset.

ii) IMR is cleared.

iii) IR7 input is assigned the lowest priority.

iv) slave mode address is set to 7

v) special mask mode is cleared and the status read is set to IRR.