8085 Program to convert two-digit hex to two ASCII values

Now let us see a program of Intel 8085 Microprocessor. This program will convert 8-bit numbers to two digit ASCII values.

Problem Statement

Write 8085 Assembly language program where an 8-bit binary number is stored in memory location 8050H. Separate each nibbles and convert it to corresponding ASCII code and store it to the memory location 8060H and 8061H.

Discussion

In this problem we are using a subroutine to convert one hexa-decimal digit (nibble) to its equivalent ASCII values. As the 8-bit number contains two nibbles, so we can execute this subroutine to find ASCII values of them. We can get the lower nibble very easily by masking the upper nibble, and for the upper nibble, we have to mask the lower nibble at first, then rotate the register content dour times to the right to make, now we can change it to ASCII values.

Here we will put 3AH as input, the program will return 33 and 41. These are the ASCII values of 3 and A respectively.

Input

Address	Data
. . .	. . .
8050	3A
. . .	. . .

Flow Diagram

Program

Address	HEX Codes	Labels	Mnemonics	Comments
8000	31, 00, 81		LXI SP, 8100	Initialize SP
8003	21, 50, 80	START	LXI H, 8050H	Initialize pointer with the first location of IN-BUFFER
8006	11, 60, 80		LXI D, 8060H	Initialize pointer with the first location of OUT-BUFFER
8009	7E		MOV A, M	Move the contents of 8050H to A
800A	47		MOV B, A	Copy A to B
800B	0F		RRC	Rotate accumulator right 4 times
800C	0F		RRC
800D	0F		RRC
800E	0F		RRC
800F	CD, 1A, 80		CALL ASCII	This subroutine converts a binary no. toASCII
8012	12		STAX D	Store the contents of the accumulator specified the contents by DE register pair
8013	13		INX D	Go to next location
8014	78		MOV A, B	Copy B to A
8015	CD, 1A, 80		CALL ASCII	This subroutine converts a binary no. toASCII
8018	12		STAX D	Store the contents of the accumulator specified the contents by DE register pair
8019	76		HLT	Terminate the program
801A	E6, 0F	ASCII	ANI 0FH	Converts a BCD number to its corresponding ASCII value + 48 0 To 9 -----------------à48 To 57 + 55 A To F -----------------à 65 To 70 + 48 +7 So +48 is common but if the hex digit is between A to F then +7 is additional.
801C	FE, 0A		CPI 0AH
801E	DA, 23, 80		JC CODE
8021	C6, 07		ADI 07H
8023	C6, 30	CODE	ADI 30H
8025	C9		RET	Returning control to the calling program