Basic Organization of Microcomputer

1. MP

    i. ALU

• This unit executes all arithmetic and logical operations as specified by instruction set; and produces output.
• The results of addition, subtraction, and logical operations (AND, OR, XOR) are stored in the registers or in memory unit or sent to output unit.

    ii. Register unit

• Consists of various registers.
• Used for temporary storage of data during execution of data.

    iii. CU

• Controls the operations of different instructions.
• Provides necessary timing and control signals to all the operations in the MP and peripherals including memory.

2. Memory

• Stores binary information such as instruction and data, and provide these information to MP when required.
• To execute programs, the MP reads data and instructions from memory and performs the computing operations.

3. System bus

• The system bus is a communication path between MP and peripherals.
• It is used to carry data, address and control signals.
• It consists:

Data bus: carries data

Address bus: carries address

Control bus: carries control signals

4. I/O bus

• Input unit is used to input instruction or data to the MP externally.
• Output unit is used to carry out the information from the MP unit.