Connect a push button switch to P3.4 and an 8 Ohm speaker to P1.0 as shown below

Question

Connect a push button switch to P3.4 and an 8 Ohm speaker to P1.0 as shown below. The 2N5307 is a Darlington transistor pair which has a current gain of beta > 2000 and its collector current can be up to 1.2 amps. If you output a square wave on P1.0 at frequency f_0 you will hear a tone on the speaker with a base frequency f_0 plus odd harmonic overtones. For this assignment write the assembly-code to output an A-note (about 440Hz) in response to the push button on P3.4. Your assembly code must contain a subroutine which does the software time delay and a macro which output a bit to P1.0. Do a demo of your program in class on the due date and turn in the following: 1. A cover sheet with your name, assignment number, and the date turned in. 2. A hard copy of your commented assembly-code

Explanation / Answer

MODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255
.CODE
START:
MOV AX,@DATA ;Initialize Data segment
MOV DS,AX
MOV DX,CONTROL
MOV AL,80H ;Initialize all ports as output
OUT DX,AL ;Ports

MOV BL,FFH ;Take FFH in BL analog equivalent to 5V
RAMP : MOV DX,PORTB
MOV AL,BL ;Copy to AL
OUT DX,AL ;And output it on the port
DEC BL ; To generate ramp wave this 5V is continuously decreased till 0V
JNZ RAMP ; Jump to RAMP if not 0
MOV BL,FFH ; To generate same wave this procedure is repeated
JMP RAMP
INT 03H
END START

MODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ; Initialize all ports as output
OUT DX,AL ; Ports
UP: MOV DX,PORTB
MOV AL,00H ;Output 00 for 0V level
CALL OUTPUT
MOV AL,0FFH ;Output FF for 5V level
CALL OUTPUT
JMP UP
OUTPUT:
OUT DX,AL
CALL DELAY
INT 21H

DELAY:
MOV CX,0FFH ; To vary through frequency alter the delay count
LUP1 LOOP LUP1
INT 21H

END START

MODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ; Initialize all ports as output
OUT DX,AL ; Ports

BEGIN:
MOV DX,PORTB
MOV AL,00H ; Output 00 for 0V level
UP: CALL OUTPUT
INC AL ; To raise wave from 0V to 5V increment AL
CMP AL,00H
JNZ UP ; Jump UP till rising edge is reached i.e. 5V

MOV AL,0FFH
UP1: CALL OUTPUT
DEC AL ; To fall wave from 5V to 0V decrement AL
CMP AL,0FFH
JNZ UP1 ; Jump UP till falling edge is reached i.e. 0V
JMP BEGIN

OUTPUT:
OUT DX,AL
CALL DELAY
INT 21H

DELAY:
MOV CX,07H ;To vary the frequency alter the delay count
LUP1:LOOP LUP1
INT 21H

END START

MODEL SMALL
.STACK 100
.DATA

CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ;Initialize all ports as output
OUT DX,AL ;Ports

UP: MOV DX,PORTB
MOV AL,00H ;Output 00 for 0V level
CALL OUTPUT ; And wait for some time
MOV AL,0FFH ;Output FF for 5V level
CALL OUTPUT ; And wait for some time
MOV AL,07FH ;Output 7F for 2.5V level
CALL OUTPUT ; And wait for some time
JMP UP

OUTPUT: OUT DX,AL
MOV CX,FFH
DELAY: LOOP DELAY ; To add DELAY
INT 03H
END STARTMODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255
.CODE
START:
MOV AX,@DATA ;Initialize Data segment
MOV DS,AX
MOV DX,CONTROL
MOV AL,80H ;Initialize all ports as output
OUT DX,AL ;Ports

MOV BL,FFH ;Take FFH in BL analog equivalent to 5V
RAMP : MOV DX,PORTB
MOV AL,BL ;Copy to AL
OUT DX,AL ;And output it on the port
DEC BL ; To generate ramp wave this 5V is continuously decreased till 0V
JNZ RAMP ; Jump to RAMP if not 0
MOV BL,FFH ; To generate same wave this procedure is repeated
JMP RAMP
INT 03H
END START



;SQUARE WAVE GENERATOR
MODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ; Initialize all ports as output
OUT DX,AL ; Ports
UP: MOV DX,PORTB
MOV AL,00H ;Output 00 for 0V level
CALL OUTPUT
MOV AL,0FFH ;Output FF for 5V level
CALL OUTPUT
JMP UP
OUTPUT:
OUT DX,AL
CALL DELAY
INT 21H

DELAY:
MOV CX,0FFH ; To vary through frequency alter the delay count
LUP1 LOOP LUP1
INT 21H

END START

MODEL SMALL
.STACK 100
.DATA
CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ; Initialize all ports as output
OUT DX,AL ; Ports

BEGIN:
MOV DX,PORTB
MOV AL,00H ; Output 00 for 0V level
UP: CALL OUTPUT
INC AL ; To raise wave from 0V to 5V increment AL
CMP AL,00H
JNZ UP ; Jump UP till rising edge is reached i.e. 5V

MOV AL,0FFH
UP1: CALL OUTPUT
DEC AL ; To fall wave from 5V to 0V decrement AL
CMP AL,0FFH
JNZ UP1 ; Jump UP till falling edge is reached i.e. 0V
JMP BEGIN

OUTPUT:
OUT DX,AL
CALL DELAY
INT 21H

DELAY:
MOV CX,07H ;To vary the frequency alter the delay count
LUP1:LOOP LUP1
INT 21H

END START



;STAIRCASE WAVEFORM GENERATOR with 8086 using 8255

MODEL SMALL
.STACK 100
.DATA

CONTROL EQU 0FFC6H ; Control port address for 8255
PORTA EQU 0FFC0H ; Port A address for 8255
PORTB EQU 0FFC2H ; Port B address for 8255
PORTC EQU 0FFC4H ; Port C address for 8255

.CODE
START:
MOV DX,CONTROL
MOV AL,80H ;Initialize all ports as output
OUT DX,AL ;Ports

UP: MOV DX,PORTB
MOV AL,00H ;Output 00 for 0V level
CALL OUTPUT ; And wait for some time
MOV AL,0FFH ;Output FF for 5V level
CALL OUTPUT ; And wait for some time
MOV AL,07FH ;Output 7F for 2.5V level
CALL OUTPUT ; And wait for some time
JMP UP

OUTPUT: OUT DX,AL
MOV CX,FFH
DELAY: LOOP DELAY ; To add DELAY
INT 03H
END START

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