1. Components
1.1. CU
1.1.1. Controls the execution of instructions in the correct sequence
1.1.2. Sends and receives signals
1.2. ALU
1.2.1. Carries out mathematical and logic operations
1.3. Registers
1.3.1. MAR
1.3.1.1. Holds address of data or instruction to be fetched or stored
1.3.2. MDR
1.3.2.1. Temporarily holds data for the current instruction fetched from memory
1.3.3. PC
1.3.3.1. Holds memory address of next instruction to be processed
1.3.4. CIR
1.3.4.1. Holds current instruction to be executed
1.3.5. ACC
1.3.5.1. Special purpose register
1.3.5.2. Where calculation results are stored
2. Embedded Systems
2.1. Used to control the function of electronic devices such as air con, heating systems, radio alarm clocks.
2.2. They often don’t need a full OS since they perform very specific tasks and their input usually controlled by buttons or switches.
3. Purpose
3.1. Micro processor responsible for opening software and running the operating system.
3.2. Passes the instructions one by one.
4. Fetch-Decode-Execute Cycle
4.1. Fetch
4.1.1. Each instruction is fetched from memory.
4.2. Decode
4.2.1. The control unit decodes it to find out what to do.
4.3. Execute
4.3.1. The instruction is executed, which could be a calculation using the ALU or changing the PC value.