FDE cycle

• What is the first thing that happened in the fetch decode execute cycle?

  Pc passes address of the instruction to MAR
• What happens after the MAR now has the instructions address

  The address bus goes to the address
• What bus does the data come back on after the address bus has got to the data?

  Data bus
• What register does the data bus bring the contents back to?

  MDR
• What happens when the MDR has just got the data?

  passes it to the CIR
• What happends after/before the CIR gets the instructions address?

  The PC increments by one
• What happens to the data once it’s in the CIR

  it gets passed to the decoder( in the control unit)
• What happens after the decoder has decoded the instruction?

  Control signals are sent out
• (execute 1) what happens after the control signals are sent out?

  MAR = memory locaction
• (execute 1) what happens after the MAR is now the address location

  It goes on the address bus to the location
• (Execute 1) what happens once the address bus get to the location

  It reads it and brings it back on the data bus to the MDR
• (execute 1) what happens once the MDR has the data from the address location

  It passes it to the accumulator