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7. Understanding the MAR and the MDR, Cont.

  • MDR Stands for memory data register.

    • MDR is connected to the data bus.

    • Data can go in both directions: to and from memory,

      • therefore, MDR can load its data from

        • the data bus (for reading data)

        • one of the CPU registers (for storing data.)

    • A 2-1 MUX circuit selects input from one of the two.

  • Memory Circuitry:

      Understanding the MAR and the MDR

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