Data Transfer Instructions In 8085


There are 5 types of instructions sets are available in the 8085 microprocessor. Today we are going to learn about the data transfer instructions in 8085 microprocessor.

Data transfer instructions in 8085 microprocessors are used to move data between processor registers, memory, and I/O devices.

Data transfer instructions copied data from source to destination without modifying the contents of the source.

The various types of data transfer that are possible between direct data, registers, and memory locations are as follows:

Sr. NoData TransferExample
1.Between registersRegister B -> Register D
2.Specific data byte to register or a memory locationData Byte -> Register B
3.Between memory location and registerMemory Location -> Register A
4.Between the I/O device and the accumulatorInput Device -> Register A
5.Between a register pair and the stackRegister Pair data -> Stack Location

The data transfer instructions in 8085 include the following instructions:

1.MOV Rd, Rs2.MOV R, M3.MOV M, R
4.MVI R, data5.MVI M, data6.LXI Rp, 16-bit data
7.LDA address8.STA address9.LHLD address
10.SHLD address11.LDAX Rp12.STAX Rp

Now, we will see each instruction which we have to describe above table in detail.


MOV Rd, Rs

Mnemonics MOV Rd, Rs
Operation Rd = Rs
No. of Bytes1 byte
Machine Cycles1 (OF)
Algorithm Rd <- Rs
Flags No flags are modified
Addr. Mode Register addressing mode
T-States 4
Description This instruction copies data from source register Rd to the destination register Rs.
The source register Rd and destination register Rs can be any general-purpose register like A, B, C, D, E, H, or L.
The contents of the source register remain unchanged.
This instruction will copy the contents of register C to register B. The contents of register C remain unchanged.
Example MOV B, C
Suppose B = 20H, C = 10H and the instruction MOV B, C is executed. After the execution B 10H and C= 10H.

Machine Cycle Details:

  1. Opcode Fetch : For this cycle the addressgiven by program counter. The program counter places the address on the lower order address bus and the higher order address bus. The program counter is incremented by one to point to next instruction.
Previous article8254 programmable interval timer
Next articleShort Notes
Electronics Engineering(2014 pass out) Junior Telecom Officer(B.S.N.L.) Project Development, PCB designing Teaching of Electronics Subjects



Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.