We know a CPU connect with Memory with Address Bus, Control Bus, Data Bus.

When CPU want to write 11110000 into Memory 0x0001, it will

first, Address Bus locate to Memory address.
then, Send Control Bus instruction(write), to Memory.
at last, CPU will send the data 11110000 to Memory.

I want to know why Memory can use Control instruction and Data to update the memory data. Is there any register and some instruct for update memory data in Memory device?


Google -> https://www.google.com/search?q=memory+write+cycle+timing+diagram

Memory writes in general are a series of signal level transitions more than having any kind of resemblance/similarity to a "CPU machine code instruction" (CPU internal micro-code disregarded).

A CPU "move" (Motorola 68k mnemo syntax, may be "store" or "load" in other assembler syntax'es) is defined to generate the sequence of signals required [1].

This may be more complex or timing constrained e.g. in the case of more modern / later / recent memory technologies.

[1] Set the address bus and data lines to the relevant state. Then set the control bus signal lines to the required states, using the sequence that is required.

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