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16 Cards in this Set
- Front
- Back
Registers |
Registers are storage locations within the processor that are used for specific tasks They are used to store data and instructions whilst they are being manipulated or executed |
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Control Unit |
Coordinates the activities taking place in the CPU, memory and peripherals by sending control signals to various devices 1. Decide which instruction to execute next then fetch it 2. Decipher that instruction, work out what needs to be done to carry out the instruction. 3. It has to tell the other parts of the processor what they should do to execute the instruction. |
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Memory Unit |
The memory unit stores everything that the processor is going to use. This includes the program instructions and the data needed to carry out the instructions |
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Arithmetic Logic Unit |
1. The ALU contains the circuitry that allows is to carry out arithmetic operations 2. It allows logical decisions to be made. 3. The ALU also acts as a gateway between the processor goes into the ALU and waits there while the control unit decides what to do |
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Program Counter |
The program counter keeps track of where in the computers memory the next instruction can be found so the next instruction can be placed in the CIR |
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Memory Address Register |
Used to hold address that contains the next instruction, or piece of data to be used |
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Memory Data Register |
Used to temporarily store data read from or written to memory |
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Accumulator |
Performs arithmetic functions |
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How registers are used |
1. The address if the next instruction is copied from PC to the MAR 2. The instruction held at that address is copied to the MDR at the same time the content of the PC is incremented so it holds the address of the next instruction 3. The contents of the MDR are copied to the CIR 4. The instruction held in the CIR is decoded 5. The instruction is executed |
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RAM/ROM |
RAM - Volatile - When computer is turned off the data is deleted ROM - Non- Volatile - Permanently attached on to the computer chip |
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Transfer between primary and secondary memory |
1. The processor needs to work on some data that is stored in secondary memory 2. The processor can only work with data in the primary memory so the data needs to be transferred from secondary to primary 3. The CPU tells secondary memory it wants the data 4. The data in SM is slowly written in to a fast piece of memory called a buffer. Whilst this is happening the processor is working on other tasks 5. When the buffer is full an interrupt is sent to the CPU telling if the data is ready and the data is read from the buffer to PM where it is manipulated by the processor |
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Bus |
A bus is a set of parallel wires connecting two or more components of a computer system |
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Control Bus |
Bidirectional so signals can be carried in both directions The data and address buses are shared by many components of the computer system. The control bus is used to ensure that the use of the address and data bus does not lead to conflict |
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Data Bus |
Provides a bidirectional path for moving data and instructions between system components |
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Address Bus |
When the CPU wishes to access a particular memory location it sends this address to memory on the address bus |
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Connectivity |
Physical 1. Twisted Pair copper cable 2. Coaxial Cable 3. Fibre Optic Cable Wireless 1. WiFi 2. Bluetooth 3. Infrared 4. Satellite |