Learn: MAR - Storing the Address

Welcome!You've already studied how registers work, including the Program Counter and Accumulator. Today, we'll focus on the Memory Address Register (MAR), a crucial part of the CPU's function during the fetch-decode-execute cycle.

What is the Memory Address Register?The Memory Address Register (MAR) is a special register in the CPU. It stores the memory address of the data or instruction that the CPU wants to access from RAM or write to RAM. This ensures the CPU knows where to find or store information.

How does the MAR work?During the fetch phase of the fetch-decode-execute cycle, the MAR receives the address of the next instruction from the Program Counter (PC). The MAR then sends this address to RAM, allowing the CPU to fetch the corresponding data or instruction.

How does the MAR interact with other components?The MAR works closely with the Memory Data Register (MDR). While the MAR holds the memory address, the MDR holds the actual data fetched from or written to that address. Together, they ensure smooth communication between the CPU and memory.

Why is the MAR important?Without the MAR, the CPU wouldn't know where to find or store data in memory. It ensures that the CPU can quickly locate the correct memory address during the fetch-decode-execute cycle. This helps the computer run programs efficiently.

Review Time!Great work! You've learned about the Memory Address Register (MAR), its role in the CPU, and how it interacts with other components. Now let's review everything you've learned with a few questions.