11.2.1. Memory Address and Data Operations

Now, what you will do now we have to read of memory data register to the register 𝑅1 that is you have to do this part that memory data register value will has to be dumped to register 𝑅1. So, only after that 𝑀𝐹𝐶 signal has become 1, you can make the memory data register signal as out. Because before that if you see the memory data signal was a 1 over here in one that is memory data register in was a 1 that means it was reading from the memory. This 𝑀𝐹𝐶 signal is saying that the reading is over. So, now, you make 𝑀𝐷𝑅_𝑜𝑢𝑡 = 1 that means now it will dump the value whatever was in the memory data register which is taken from the memory to the bus. And then 𝑅 = 1 that means, whatever was in the memory data register will dump to the register 𝑅1 and this instruction of 𝑀𝑂𝑉 𝑅1, 32 will be over.

In this chunk, we are discussing how data is transferred from the memory data register (MDR) to register R1. The process starts when the MDR value is ready to be read. The MFC signal indicates that reading is complete, allowing the MDR to output its value. This value then gets stored in register R1. Essentially, the reading of the memory address specified (32 in this case) concludes with the MOV instruction, completing the operation of moving data into R1.

Imagine checking out a book from a library. The book is stored on a shelf (the memory data register). When you're ready to read it (MFC signal indicates it's ready), you take it off the shelf (output it from MDR) and place it in your bag (register R1). Once in your bag, you can read it whenever you like (the data is now in R1 for use).

Now, let us very quickly see that if this is the reverse one that is if there is something in memory register 𝑅1 sorry if there is some value in 𝑅1, we want to dump it to memory looking at 32; one was the read operation, next was the right operation very simple. Of course, first the value of 𝑅1 has to be written to 32. So, the register value 𝑅 instruction register has to be made 1, 𝑜𝑢𝑡 because the default idea is that whatever instruction is there will be first in the instruction register.

This part explains the process of writing data from register R1 back to memory at address 32. Initially, the value in R1 needs to be transferred to the instruction register (IR). The IR will then determine where to store the data, which in this instance is at the memory address specified by the value (32). The importance of setting the IR to output mode (IR out) allows the data to be properly directed to the memory address register (MAR).

Consider how you might want to return a library book. You first take the book you have (R1) and place it in a box designated for returns (IR). Once it's in the box, it gets delivered to the library (the memory), so that others can borrow it. Setting the box to output mode ensures the book reaches the right place.

So, the value of 32 from the instruction register will be dumped to the memory instruction register.

Here, the section highlights the role of the instruction register (IR) in managing memory operations. The value 32, indicating which memory cell to write to, is transferred to the memory address register (MAR). This operation is crucial as it allows the system to know precisely where the data from R1 should be stored.

It’s similar to writing down an address on an envelope before sending a letter. You need to ensure the correct address (32) is on the envelope before mailing it, so it arrives at the right destination.

And now, we are giving a 𝑤𝑟𝑖𝑡𝑒 command. The write command is basically an external signal; all others are internal signals which is generated by the control unit.

This chunk covers the execution of the write command. Once the memory address is set, the control unit sends an external 'write' signal indicating that it is time to transfer data. This signal creates the necessary condition for the memory data register to output its contents to the correct memory cell, thereby completing the write operation.

Continuing with the library analogy, once the address is on the envelope, you need to send it off (the write command). This sends a clear signal to the mail service that your letter needs delivering.

After some amount of time when the 𝑀𝐹𝐶 signal will be say memory has been written. So, after this clock edge basically you can again I have not shown this, but again you can in this point you can make this signal down over here.

Finally, after the memory write operation completes, the control unit waits for a feedback signal (MFC) confirming that the memory has indeed processed the write request. This synchronization step ensures stable communication between the CPU and memory, preventing any conflicts brought on by premature signaling.

Think of it like confirming with the mail service that your letter (data) has been delivered successfully to the recipient (memory). Once you receive confirmation, you can stop keeping track of that particular mail.

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