Interface a stepper motor with 8085

Program Name

Write a Assembly Language Program for Interface a stepper motor with 8085 .

Theory

Instruction Mnemonic	Operand	Comments
MVI	A,80	Load accumulator with 80H to configure CWR of 8255.
OUT	CWR	Configure CWR to display output with accumulator value. i.e 80
MVI	A,88H	To make a complete 360 rotation we need ‘1’ at D7 and D3….pass 88H.
OUT	PA	Send the value 88H through output port A.(which is displayed on screen as single dot).
CALL	DLY	Call delay to halt the motor after half rotation
RLC		Rotate the bits to the left
JMP	XX	Jump back to send the value through output to continue the rotation

Delay Code

Instruction Mnemonic	Operand	Comments
PUSH	PSW	Initialize process status word.
LXI	D,FFFF	Initialize D register with maximum 16 bit value.
DCX	D	Decrement D.
MOV	A,D	Move the value of D into accumulator.
DRA	E	Perform OR operation on accumulator and E to decrement E.
JNZ	YY	Jump if the value at D is not zero.
POP	PSW	Remove value from process status word.
RET		Return back to main routine.

Program Code


MVI	A,80
OUT	CWR
MVI	A,88H
OUT	PA
CALL	DLY
RLC	
JMP	XX

//Delay Code
PUSH	PSW
LXI	D,FFFF
DCX	D
MOV	A,D
DRA	E
JNZ	YY
POP	PSW
RET

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