Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Fetch Execute Cycle The fetch – execute cycle has 2 phases: 1.The fetch phase is where the instruction is copied into the control unit and decoded.

Similar presentations


Presentation on theme: "The Fetch Execute Cycle The fetch – execute cycle has 2 phases: 1.The fetch phase is where the instruction is copied into the control unit and decoded."— Presentation transcript:

1 The Fetch Execute Cycle The fetch – execute cycle has 2 phases: 1.The fetch phase is where the instruction is copied into the control unit and decoded (memory READ operation) 2.The execute phase is where the instruction is carried out (memory WRITE)

2 CU Arithmetic and Logic Unit (ALU) Other registers MAR MDR DATA Address bus Data bus Control Bus (Read / Write) Electronic clock Clock pulses ADDRESS 0000 READ 1101 Memory READ Operation

3 1. Memory Read Operation i.CPU sets up address bus by placing a value in the Memory Address Register ii.The Control Unit activates the read line on the control bus iii.The contents of the storage location are released onto the data bus and copied into the CPU’s Memory Data Register Memory READ Operation

4 CU Arithmetic and Logic Unit (ALU) Other registers MAR MDR DATA Address bus Data bus Control Bus (Read / Write) Electronic clock Clock pulses ADDRESS Memory WRITE Operation WRITE 1111

5 2. Memory Write Operation i.CPU sets up the address bus by placing the required memory address in the Memory Address Register ii.CPU sets up the data bus by placing the value to be written in the Memory Data Register iii. The control unit activates the write line on the control bus iv.The contents of the MDR are transferred to the required storage location in memory Memory WRITE Operation


Download ppt "The Fetch Execute Cycle The fetch – execute cycle has 2 phases: 1.The fetch phase is where the instruction is copied into the control unit and decoded."

Similar presentations


Ads by Google