Learn: Memory Address Register (MAR)

Welcome!Welcome back! You've already learned about the CPU and its components, including registers like the Program Counter (PC) and Accumulator (ACC). Today, we'll explore the Memory Address Register (MAR), a key register in the fetch–execute cycle.

What is the MAR?The Memory Address Register (MAR) stores the address of the memory location that the CPU needs to access. This could be the location of an instruction or data. It acts as a pointer, telling the CPU where to look next.

How Does the MAR Work?During the fetch stage of the fetch–execute cycle, the Program Counter (PC) sends the address of the next instruction to the MAR. The MAR then passes this address to the memory, allowing the CPU to fetch the required data or instruction.

Why is the MAR Important?The MAR ensures the CPU knows exactly where to find the next instruction or piece of data in memory. Without it, the CPU wouldn't be able to locate memory efficiently, slowing down processing and causing errors.

How Does the MAR Relate to the MDR?The Memory Data Register (MDR) works alongside the MAR. While the MAR holds the address pointing to a memory location, the MDR temporarily stores the data fetched from that location or the data to be written to that location.

Review Time!Great work! You've learned about the Memory Address Register and its role in the CPU. Now let's test your understanding with a few more questions.