Which ports are mainly utilised for address and data lines when interfacing external RAM with the 8051 microcontroller?

Question

Question

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RRB JE CBT 2 (Electronics Engineering) ReExam Official Paper (Held On: 04 Jun, 2025)

Answer 1

The correct answer is option 4

Explanation:

When interfacing external RAM with the 8051 microcontroller, the 8051 needs to output address and data signals to the external memory.

The 8051 uses:

Port 0: Multiplexed lower 8 bits of address (A0–A7) and data bus (D0–D7).
(This is why an external latch is needed to demultiplex address & data.)
Port 2: Outputs the higher 8 bits of address (A8–A15) directly.