CPU Fetch/Execute Cycle Computer program Electronic clock Computer Memory Data/address buses Fetch/Execute Cycle Accumulator ALU/Control Unit/Program Counter CIR/MDR/MAR
Simple Microprocessor Memory Electronic Clock Arithmetic Logic Unit Accumulator Control Unit Memory Address Register Current Instruction Register Memory Data Register Program Counter Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus
Simple Microprocessor Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R)
Simple Microprocessor Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 100 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R)
Fetch Phase (1 st Instruction) Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 100 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R)
1 st Instruction Decoded Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 101 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R) Load number from memory location 10
1 st Instruction Executed Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 101 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R) Load number from memory location
Fetch Phase (2 nd Instruction) Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 101 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R) PC = 102
2nd Instruction Decoded Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 102 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R) Load number from memory location
2nd Instruction Execution Memory Electronic Clock ALU Accumulator Control Unit MAR CIR MDR PC = 102 Internal Bus Special Internal Bus Structure Data Bus Data BusData Bus Data Bus Internal Bus Address Bus Data bus … (2) (3) (R)