GATE 2014 EC (EC2) – Question 52
The figure shows an 8085 interface for input of eight-bit digital data DI₀–DI₇ from an external device. Which instruction transfers it correctly?
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Correct answer: (D) LDA F8F8H
Explanation
The decoder enables on a memory read: IO/M=0 and RD low. Address bits A2–A0are000, A7–A3are11111, and the upper-address gate requires A15–A8=11111000. Thus the device is memory-mapped atF8F8H. Loading its byte into the accumulator requires **LDA F8F8H,D**. IN F8H would issue an I/O read instead.