8051 code to convert hexadecimal to ascii value

In this article let's learn how to convert Hexadecimal value to Ascii equivalent number.

Hexadecimalvalue	Asciivalue
01H	31H
02H	32H
03H	33H
04H	34H
05H	35H
06H	36H
07H	37H
08H	38H
09H	39H
0AH	41H
0BH	42H
0CH	43H
0DH	44H
0EH	45H
0FH	46H

Algorithm:

 1)Initialize R0 with number which is required to find equivalent Ascii code.
 2)Compare it with 0AH and jump to label1 if it is equal.
3)Compare the carry bit to find which is greater and lesser.
4)If the carry bit is not set(it implies it is greater)jump to label2.
 5)If it is lesser add the number with 30H.
6)If it is greater add the number with 37H.

Code goes here:

ORG 0000h
LJMP MAIN
ORG 40h
MAIN:  MOV R0,#01H         ; move the numbers to be converted
       MOV A,R0
       CJNE A,#0AH,LABEL1  ; compare the number with A
LABEL1:JNC LABEL2          ;If the number is greater than A jump to label2
       ADD A,#30H          ; If the number is lesser than A add with 30H
       SJMP STOP
LABEL2:ADD A,#37H          ;If the number is greater than A add with 37H
STOP:
       END