An example of the CPU reading/writing memory process

Memory read operation. For example, if you want to read out the content 50H in memory 40H, the process is as follows:

①The CPU sends the address code 40H to the address bus, and the memory address decoder selects the storage unit with address 40H:

②The CPU sends a "defilement" signal, and the memory read/write control switch turns the data transmission direction to "read";

③The memory sends the content 50H in the storage unit with address 40H to the data bus;

④The CPU reads the data 50H on the data bus into a specified register.

The reading operation of the storage unit will not destroy its original content, which is equivalent to copying.

2) Memory write operation. For example, if you want to write data ABH into the memory cell with memory address CDH, the process is as follows:

①The CPU sends the address code CDH to the address bus, and the memory address decoder selects the storage unit with the address CDH;

②CPU sends data ABH to the data bus;

③The CPU sends a "write" signal, and the memory read/write control switch turns the data transfer direction to "write";

④ The memory sends the data ABH on the data bus to the selected storage unit with address CDH.

The write operation on the storage unit changes or refreshes its original content, commonly known as "flushing" the original content.