Fetch Decode Execute Cycle

1.     The fetch Stage
The program counter contains the address of the next instruction which is ready to be executed. The contents of the PC are copied to the Memory Address Register or MAR. This is connected to the address bus. The address of the next instruction going to executed is placed on the address bus and then the Control Unit sends a signal to read it. This finds the contents of the memory location and transfers it to the processor.

The instruction stored at that address is transferred using the data bus riding from main memory to the processor. It is then saved in the…