Countdown ( Pencacah Mundur ) Timer Menggunakan AT89c2051

Sebuah count-down (Pencacah mundur) timer sederhana menggunakan display LED yang mampu mencacah dalam beberapa menit dan detik. Tiga tombol dibawah LED digunakan untuk mengeset menit, detik dan tombol kontrol start/stop. Bila pencacahan telah selesai maka Alarm Buzzer akan berbunyi dan display LED menampilkan angka Nol. Alarm Buzzer akan berhenti berbunyi dengan menekan tombol start/stop. Rangkaian count-down (Pencacah mundur) timer dibangun menggunakan microcontoller keluarga mcs-51 yaitu AT89c2051.

Gambar Rangkaian count-down (Pencacah mundur) timer menggunakan AT89c2051.

Source code.

;@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

;PROGRAM FOR TIMER

;@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

include REG_52.PDF

RB0 EQU 000H ; Select Register Bank 0

RB1 EQU 008H ; Select Register Bank 1 ...poke to PSW to use

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

; PORT DECLERATION

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

DIS_A EQU P1.5

DIS_B EQU P1.4

DIS_C EQU P1.3

DIS_D EQU P1.1

DIS_E EQU P1.2

DIS_F EQU P1.6

DIS_G EQU P1.7

DIS1 EQU P1.0

DIS2 EQU P3.7

DIS3 EQU P3.5

DIS4 EQU P3.4

START EQU P3.0

STOP EQU P3.1

RESETS EQU P3.2

BUZZER EQU P3.3

DSEG ; This is internal data memory

ORG 20H ; Bit adressable memory

COUNT: DS 1

SPEED: DS 1

VALUE_1: DS 1

VALUE_2: DS 1

VALUE_3: DS 1

VALUE_4: DS 1

NUMB1: DS 1

NUMB2: DS 1

NUMB3: DS 1

NUMB4: DS 1

SEC: DS 1

MIN: DS 1

FINAL: DS 1

FIN: DS 1

TENS: DS 1

STACK DATA 3FH

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

CSEG AT 0 ; RESET VECTOR

;---------==========----------==========---------=========---------

; PROCESSOR INTERRUPT AND RESET VECTORS

;---------==========----------==========---------=========---------

ORG 00H ; Reset

JMP MAIN

ORG 000BH ;Timer Interrupt0

JMP REFRESH

;---------==========----------==========---------=========---------

; Main routine. Program execution starts here.

;---------==========----------==========---------=========---------

MAIN:

MOV PSW,#RB0 ; Select register bank 0

MOV SP,STACK

MOV SPEED,#00H

MOV COUNT,#00H

CLR DIS1

CLR DIS2

CLR DIS3

CLR DIS4

MOV TMOD,#01H ;enable timer0 for scanning

MOV TL0,#00H

MOV TH0,#0FDH

SETB ET0

SETB EA

SETB TR0 ;Start the Timer

MOV VALUE_1,#15H

MOV VALUE_2,#15H

MOV VALUE_3,#15H

MOV VALUE_4,#15H

CLR BUZZER

TOP1: SETB START

JB START,$

SETB BUZZER

MOV SEC,#00H

MOV MIN,#00H

TOP:

SETB STOP

MOV R3,#05H ;1 SEC DELAY

REP3: MOV R1,#0BFH

REP2: MOV R2,#0FFH

REP1: JNB STOP,TIM_STOP1

DJNZ R2,REP1

DJNZ R1,REP2

CLR BUZZER

DJNZ R3,REP3

INC SEC

MOV A,MIN

CJNE A,#04H,FGV1

MOV A,SEC

CJNE A,#40,FGV1

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

TIM_STOP1: AJMP TIM_STOP

FGV1: MOV A,MIN

CJNE A,#09H,FGV2

MOV A,SEC

CJNE A,#40,FGV2

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

FGV2:

MOV A,MIN

CJNE A,#14,FGV3

MOV A,SEC

CJNE A,#40,FGV3

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

FGV3:

MOV A,MIN

CJNE A,#19,FGV4

MOV A,SEC

CJNE A,#40,FGV4

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

FGV4:

MOV A,MIN

CJNE A,#24,FGV5

MOV A,SEC

CJNE A,#40,FGV5

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

FGV5:

MOV A,MIN

CJNE A,#29,FGV6

MOV A,SEC

CJNE A,#40,FGV6

SETB BUZZER

CALL DELAY

CLR BUZZER

CALL DELAY

SETB BUZZER

AJMP DOWN1

FGV6:

DOWN1:

MOV A,SEC

CJNE A,#60,DCF1

MOV SEC,#00H

INC MIN

SETB BUZZER

MOV A,MIN

CJNE A,#60,DCF1

MOV MIN,#00H

DCF1: MOV R2,SEC

ACALL HEX2BCD

MOV VALUE_4,R3 ;MOV LSB TO DISPLAY

MOV VALUE_3,R4

MOV R2,MIN

ACALL HEX2BCD

MOV VALUE_2,R3 ;MOV LSB TO DISPLAY

MOV VALUE_1,R4

AJMP TOP

TIM_STOP:

SETB BUZZER

CALL DELAY

CLR BUZZER

JNB STOP,$

CALL DELAY

JB STOP,$

SETB BUZZER

CALL DELAY

CLR BUZZER

MOV SEC,#00H

MOV MIN,#00H

MOV VALUE_1,#15H

MOV VALUE_2,#15H

MOV VALUE_3,#15H

MOV VALUE_4,#15H

AJMP TOP1

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

; 7 SEGMENT DISPLAY ROUTINE

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

DISP:

MOV R2,SPEED

CJNE R2,#00H,AAS1

CLR DIS_A

CLR DIS_B

CLR DIS_C

CLR DIS_D

CLR DIS_E

CLR DIS_F

SETB DIS_G

RET

AAS1: CJNE R2,#01H,AS2

CLR DIS_B

CLR DIS_C

SETB DIS_A

SETB DIS_D

SETB DIS_E

SETB DIS_F

SETB DIS_G

RET

AS2: CJNE R2,#02H,AS3

CLR DIS_A

CLR DIS_B

CLR DIS_D

CLR DIS_E

CLR DIS_G

SETB DIS_C

SETB DIS_F

RET

AS3: CJNE R2,#03H,AS4

CLR DIS_A

CLR DIS_B

CLR DIS_C

CLR DIS_D

CLR DIS_G

SETB DIS_E

SETB DIS_F

RET

AS4: CJNE R2,#04H,AS5

CLR DIS_B

CLR DIS_C

CLR DIS_F

CLR DIS_G

SETB DIS_A

SETB DIS_D

SETB DIS_E

RET

AS5: CJNE R2,#05H,AS6

CLR DIS_A

CLR DIS_C

CLR DIS_D

CLR DIS_F

CLR DIS_G

SETB DIS_B

SETB DIS_E

RET

AS6: CJNE R2,#06H,AS7

CLR DIS_A

CLR DIS_C

CLR DIS_D

CLR DIS_E

CLR DIS_F

CLR DIS_G

SETB DIS_B

RET

AS7: CJNE R2,#07H,AS8

CLR DIS_A

CLR DIS_B

CLR DIS_C

SETB DIS_D

SETB DIS_E

SETB DIS_F

SETB DIS_G

RET

AS8: CJNE R2,#08H,AS9

CLR DIS_A

CLR DIS_B

CLR DIS_C

CLR DIS_D

CLR DIS_E

CLR DIS_F

CLR DIS_G

RET

AS9: CJNE R2,#09H,AS10

CLR DIS_A

CLR DIS_B

CLR DIS_C

CLR DIS_D

CLR DIS_F

CLR DIS_G

SETB DIS_E

RET

AS10: CJNE R2,#15H,AS11 ;symbol for -

SETB DIS_A

SETB DIS_B

SETB DIS_C

SETB DIS_D

SETB DIS_E

SETB DIS_F

CLR DIS_G

RET

AS11: CJNE R2,#16H,AS12 ;switch off all disp

SETB DIS_A

SETB DIS_B

SETB DIS_C

SETB DIS_D

SETB DIS_E

SETB DIS_F

SETB DIS_G

RET

AS12: MOV SPEED,#00H

AJMP DISP

;**********************************************************

; INTRRUPT ROUTINE TO REFRESH THE DISPLAY

;**********************************************************

REFRESH:

PUSH PSW ; save current registerset

MOV PSW,#RB1

PUSH ACC

INC COUNT

MOV R4,COUNT

QA1: CJNE R4,#01H,QA2

MOV SPEED,VALUE_1

SETB DIS1

CLR DIS2

CLR DIS3

CLR DIS4

CALL DISP

AJMP DOWN

QA2: CJNE R4,#02H,QA3

MOV SPEED,VALUE_2

CLR DIS1

SETB DIS2

CLR DIS3

CLR DIS4

CALL DISP

AJMP DOWN

QA3: CJNE R4,#03H,QA4

MOV SPEED,VALUE_3

CLR DIS1

CLR DIS2

SETB DIS3

CLR DIS4

CALL DISP

AJMP DOWN

QA4: CJNE R4,#04H,QA5

MOV SPEED,VALUE_4

CLR DIS1

CLR DIS2

CLR DIS3

SETB DIS4

CALL DISP

AJMP DOWN

QA5: MOV COUNT,#01H

MOV R4,COUNT

AJMP QA1

DOWN: MOV TL0,#0FFH

MOV TH0,#0F0H

POP ACC

POP PSW

RETI

;**********************************************************

DELAY:

MOV R1,#0FFH

RAP2: MOV R2,#0FFH

RAP1: NOP

DJNZ R2,RAP1

DJNZ R1,RAP2

RET

;**********************************************************

Hex2BCD:

MOV R1,#00H ; MSByte

MOV R3,#00D

MOV R4,#00D

MOV R5,#00D

MOV R6,#00D

MOV R7,#00D

CALL H2B

RET

H2B: MOV B,#10D

MOV A,R2

DIV AB

MOV R3,B ;

MOV B,#10 ; R7,R6,R5,R4,R3

DIV AB

MOV R4,B

MOV R5,A

CJNE R1,#0H,HIGH_BYTE ; CHECK FOR HIGH BYTE

SJMP ENDD

HIGH_BYTE:

MOV A,#6

ADD A,R3

MOV B,#10

DIV AB

MOV R3,B

ADD A,#5

ADD A,R4

MOV B,#10

DIV AB

MOV R4,B

ADD A,#2

ADD A,R5

MOV B,#10

DIV AB

MOV R5,B

CJNE R6,#00D,ADD_IT

SJMP CONTINUE

ADD_IT:

ADD A,R6

CONTINUE:

MOV R6,A

DJNZ R1,HIGH_BYTE

MOV B, #10D

MOV A,R6

DIV AB

MOV R6,B

MOV R7,A

ENDD: RET

END

 

Source  : http://elkaubisa.blogspot.com or http://www.8051projects.info/proj.asp?ID=61