How memory read and write operations are performed in computer system?

Memory is connected to the CPU through the address register (AR), the data register (DR) and the control signals.

For a read, the CPU puts the address of the required word in AR and activates the read signal. The memory places the word on the data lines, and it is loaded into DR.

$$Read:\ DR \leftarrow M[AR]$$

For a write, the CPU puts the address in AR and the data in DR, and activates the write signal. The memory stores the word at that address.

$$Write:\ M[AR] \leftarrow DR$$

Each operation takes one memory cycle.