Program to alternately display 00 and FF in the data field in 8085 Microprocessor

Here we will see one 8085 microprocessor program. This program will generate 00H and FFH alternatively.

Problem Statement −

Write an 8085 Assembly language program that can generate 00H and FFH alternatively.

Discussion −

The 00H and FFH are changed alternatively in each second. So we need one second delay. We have created delay subroutine to generate 1s delay.

Note: Here for simplicity we are storing the numbers into memory. To show the numbers, we can use 7 – segment display and other display function for showing it into the display.

Input

Here we are not providing any input.

Flow Diagram

Program

Address	HEX Codes	Labels	Mnemonics	Comments
F000	AF	LOOP	XRA A	Clear A register
F001	32, 50, 80		STA 8050H	Store 00H at 8050H
F004	CD, 11, F0		CALL DELAY	Wait for 1 second
F007	3D		DCR A	Decrease A to get FFH
F008	32, 50, 80		STA 8050H	Store FFH at 8050H
F00B	CD, 11, F0		CALL DELAY	Wait for 1 second
F00E	C3, 00, F0		JMP LOOP	Jump to Loop
F011	0E, 02	DELAY	MVI C,02H	Initialize Count to 02H
F014	11, FF, FF	L1	LXI D,FFFFH	Load DE with FFFFH
F016	1B	L2	DCX D	Decrease DE
F017	7A		MOV A,D	Take D to A
F018	B3		ORA E	OR A and E
F019	C2, 16, F0		JNZ L2	If Z = 0, jump to L2
F01C	0D		DCR C	Decrease C by 1
F01D	C2, 13, F0		JNZ L1	Jump to L1, if Z = 0
F020	C9		RET	Return from subroutine