Addressing modes of 8051

In diploma engineering notes, we are now discuss about the different types of addressing modes of 8051 microcontroller. Poly Notes Hub‘s shares a simple discussion on this topic.

What is Addressing modes of 8051?

Addressing modes are those types of methods of microcontroller’s instruction set which is defines that how many methods we can use to program or address the microcontroller. There are basically 5 different types of addressing modes in 8051 microcontroller.

Types of Addressing modes of 8051

There are five types of addressing modes in 8051 microcontroller

1. Immediate Addressing Mode
2. Register Addressing Mode
3. Direct Addressing Mode
4. Register Indirect Addressing Mode
5. Indexed Addressing Mode

Immediate Addressing mode

In this type of addressing mode the data is immediately or directly transfer to the destination register.

For Example: MOV A, #07H

Here, 05H is the data. So, in execution this data is directly move to the Accumulator A.

Note: “#”, which is use before the data indicates that the operand is a data. If “#” is not present then it consider as a address.

Register Addressing mode

In this type of addressing mode both source and destination is register.

For Example: MOV R2,A

Here, the data of Accumulator is move to the R2.

Direct Addressing mode

In this type of addressing mode, source address is specified by using 8-bit data in the instruction and also the destination address. The internal data memory is used in this type of addressing mode.

For Example: MOV A, 13H

Here, the instruction the read out by the internal RAM of 8051 which has the a specified address and store it in Register A or Accumulator.

Register Indirect Addressing Mode

In this type of addressing mode, the source and also the destination address are given in the register. By using this method, the internal as well as external address can be access.

For Example: MOV A,M

Indexed Addressing Mode

By indexed addressing mode, from the program memory we can accessed the source memory. The operand is destination is always the Accumulator or Register A.

For Example: MOV CA,@A+PC