FUNCTION OF MICROPROCESSOR

MICROPROCESSOR & BUS

Functions perform by the Microprocessor

• Microprocessor initiated operations .
• Internal data operations .
• Peripheral operations .

Microprocessor initiated operations

Microprocessor performs the following initiated operations

Memory read       :               Read data from memory

Memory write      :               Writes data into memory

I/O Read              :               Accepts data from input devices

I/O write              :               Sends data to output devices

To communicate with a peripheral the MPU needs to perform the following steps

Step1    :               Identify the peripheral on the memory location

Step2    :               Transfer data

Step3    :               Provide timing and synchronizing signals

Internal data operations

• Store 8 bit data
• Perform arithmetic & logical operations
• Test for conditions
• Sequence the execution of instructions
• Store data temporarily during execution in the defined R/W memory locations called STACK .

External initiated operations

A microprocessor performs the following external operations like RESET , INTERRUPT , READY , HOLD

DIFFERENT BUS

Address Bus

The address bus is a group of 16 lines generally identified as A₀ to A₁₅ . The address bus is unidirectional that is data flows in one direction , from the MPU to peripheral device . The address bus identify the peripheral devices .

Data Bus

The data bus is a group of 8 lines used to transfer data from one location to another location . Data bus is bidirectional that is data or bits flow in both directions between the MPU and memory and peripheral devices .

Control Bus

The control bus is comprised of various lines that carry synchronization signals . The MPU uses such lines to provide timing and synchronization signals .

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