Flashcards
Components of the CPU - OCR Computer Science A Level
Cards in this deck (12)
- 1What is the Purpose of the Control Unit?> Overall control of the CPU
- Activates and communicates with all parts of the CPU (as well as other components of the computer)
> Mainly executes program instructions via the F.D.E. cycle
> Controls the flow of data inside and outside the CPU
- Responsible for read and write requests to memory - 2What is the Purpose of the Program Counter?> Holds the memory address of the next instruction to be fetched from RAM
- Either incremented or changed via the CIR (if the code branches, in which case the previous value is added to a stack)
> Works closely with the MAR
- At the start of every cycle, the address in the PC is copied to the MAR - 3What is the Purpose of the Memory Address Register?> Holds the address of the memory location from which data is to be read / written
> Sends the address to memory down the Address Bus - 4What is the Purpose of the Memory Data Register?> Holds the actual data received from RAM (or was written to RAM)
> This data is sent from RAM down the Data Bus - 5What is the Purpose of the Current Instruction Register?> Holds the instruction currently being executed
> Contains the opcode and operand(s) of the current instruction
- Opcode - the operation to be done to the data
- Operand - the data affected by the operation - 6What is the Purpose of the Arithmetic Logic Unit?> Performs arithmetic and logical operations of data
- Includes addition, subtraction, multiplication, division, as well as bitwise shifts and logical operations (e.g., AND, OR, NOT etc.) - 7What is the Purpose of the Accumulator?> Temporary register that stores the immediate results of calculations from the ALU
- 8What is the Purpose of the Address Bus?> Carries memory addresses from the MAR that identify where the data is being read from and written to
- 9What is the Purpose of the Data Bus?> Carries the binary data that makes up information (data and instructions) being transmitted to the MDR
- 10What is the Purpose of the Control Bus?> Carries command and control signals to and from every other component of the CPU, to ensure that everything stays synchronised
- 11Generally, what is a Bus?> A vehicle that is always dirty
or
> A group of parallel wires that connect CPU components in order to pass signals between them - 12What is a Bus Request and a Bus Grant?> Request - indicates a device is requesting the use of the Data Bus
> Grant - indicates the CPU has granted access to the Data Bus
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- A level Computer Science (Structure, Function, and Types of the Processor) Flashcards on Components of the CPU - OCR Computer Science A Level, created by Malachy Moran-Tun on 18/05/2022.
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- Malachy Moran-Tun
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- Created by Malachy Moran-Tun · Apr 4, 2022
- Copied by Malachy Moran-Tun · May 18, 2022
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