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Subtraction of two number using micro-controller

Aim: Write a program to subtract two 8-bit numbers stored in Register R0 and R1 and store the result at 4012 memory location using micro-controller kit.

Apparatus Used:  Micro-controller kit.

Assumption: Suppose the content of register R0 and R1 are 12 and 11 respectively. Write a program to subtract these values.
Algorithm: 

• Load Data into Register R0 and R1
• Move one data into accumulator.
• Subtract other data from accumulator.
• Initialize memory point to store output
• Store output at given location.

Program:

Description of used instruction:

MOV: Used for Load and Copy the Data. This copies a byte from the source location to destination.

SUB: This subtracts the source byte from the accumulator and keeps result in accumulator.

MOVX: This instruction transfer data between external memory and register.

DPTR: This is Data Pointer. It is used for containing 16 bit data or memory address.

SJMP: Short Jump loop is used for loop within program.

Result:

Input:   R0=12, R1=11

Output: A=12-11=01 and it will store at external memory 4012H.

Procedure to find output:

·         After ending (SJMP) the program, press Enter two times.

·         You will get message “Welcome to ------KIT”.

·         Press G and Provide initial address of program as in this program, starting address is 3000 H.

·         Press Enter.

·         After pressing Enter, You will get Message “Execution Completed”.

·         Press Reset on micro-controller KIT.

·         Press M and You will get Message “Enter Address”.   

·         Provide Address for Output as in this Program 4012H and Press Space and you get Output.

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