五一電子閱讀：《學單片機》—《多功能AT89C2051倒計時器》

倒計時器在生活非常有用,用單片機自制,不但電路簡單,而且功能可根據需要自行設計。由74系列、40系列小規模數字芯片設計的倒計時器非常多,但有顯示不直觀(無LED數碼管);調整參數不靈活;計時精度低(采用RC振蕩)等缺點。在此向大家介紹如何用89C2051單片機自制倒計時器的方法。

一、功能介紹

1．獨立的三路倒計時。均可獨立設置啟動、關閉。
2．范圍:0~20小時,可任意設定。關機后數據不丟失。計時精度高:<0.1S
3．.獨立的三路輸出:
a:第1路蜂鳴器輸出: 15S
b:第2路 PNP晶體管輸出:5S
c:第3路 PNP晶體管輸出:直致關機

二、工作原理

電路見上圖整機由89c2051、三位LED數碼管、K1-K4、R、T等元器件組成。89C2051內部T1定時器完成100mS定時中斷功能。為了減少硬件,由89C2051的P1口直接輸出LED的段碼,BCD轉換由軟件完成。位選碼由P3.0,P3.1,P3.7輸出。鍵盤掃描與LED位選碼的腳共用。

由于89C2051的灌入電流:20mA。故直接驅動:蜂鳴器、PNP晶體管。LED數碼管采用共陰高亮型,LED1數碼管要旋轉180度。因為要顯示:“19:99”,而只有三位數碼管,因此用第三位的數碼管的小數點表示“1”。

三、軟件編制

(軟件流程見圖三)
在T1中斷程序中做一個軟時鐘,在定時處理程序不斷查尋時間,并根據每路的啟動狀態,判別是否要減數。每路倒計時到"0"后,均要判別其它兩路是否已啟動。如果沒有啟動,則CPU進入掉電模式,電流<1.5uA,因此電路中無電源開關,再次啟動,由K4(復位鍵)完成。每路倒計數的初值、啟動狀態(是否開始倒計數),均可單獨設定并存在89c2015的RAM中,只要不斷電,數據不會改變。

四、操作說明

電路中設有K1~K4四個開關:

1．功能如下:

    K1:定時路數切換。上電:LED顯示第1路定時時間,按下k1,LED顯示第1路定時啟動狀態: 【F】表示:關 �！緉】表示:開。再按下K1后,依此進入第2路、3路的設置,最后進入關機狀態。 LED顯示:【OFF】,K3按下則關機。

    K2:小時位加1。當超過9小時后,LED1的小數位亮。表示“1”,因此LED顯示最大的定時時間:19小時。LED1安裝時要倒過來,而且最好用綠色的。K3:分位加1 、啟動狀態切換【F-n-F】、關機確認。

1、當LED數碼管顯示定時時間時,按下K3則相應路數的分位加1。范圍:0~59分鐘。
2、當LED數碼管顯示【1.F】或【2.F】或【3F】時,按下K3則【F】變為【n】,再次按下K3則【n】變為【F】,一旦進入【n】則相應路數的倒計時就啟動。
3、當LED數碼管顯示【OFF】時,表示CPU已處于關機模式,只要按下K3,則CPU進入掉電模式。

    K4:復位復位89C2051,把MCU從掉電模式拉出重新啟動。以上電路定時初值及啟動狀態均可時時改變。

2．定時初值及啟動狀態的設定:

三路定時初值及啟動狀態均可一次設置好,方法如下:

1、K1~K3鍵任意鍵按下不松約5s后,LED數碼管顯示開始閃爍,表示已進入初值和啟動狀態設定模式。
2、通過K1-K3的操作,可對三路的定時初值及啟動狀態進入設定。

四、注意事項

1、當MCU用6MHz晶振時,工作電壓可在2.6-5.5V之間。
2、外接繼電器,請注意工作電壓,及晶體管的保護。

;***************
;timer_program 2000-12-3 倒計時器源程序
;***************

timers equ 08h
;**************************************************
al1_min equ timers+1h
al1_hour equ timers+2h
al2_min equ timers+3h
al2_hour equ timers+4h
al3_min equ timers+5h
al3_hour equ timers+6h
flash equ timers+7h

;****************************************************************
del1 equ flash+1h
del2 equ flash+2h
del3 equ flash+3h ;ram addres at 12h
;*****************************************************************
key_data equ del3+1h
sec equ del3+2h
timer_no equ sec+1h
del4 equ timer_no+1h
key_power equ del4+1h

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

time_led1 equ 24h
time_led2 equ time_led1+1
time_led3 equ time_led2+1

led1 equ time_led3+1h
led2 equ led1+1
led3 equ led2+1

;*************************************************
al1_min_t equ led3+1
al1_hour_t equ al1_min_t+1

al2_min_t equ al1_hour_t+1h
al2_hour_t equ al2_min_t+1h

al3_min_t equ al2_hour_t+1h
al3_hour_t equ al3_min_t+1h
;***************************************************

beep_timer equ al3_hour_t+1h

;****************以上進行內存分配*******************

led_1 bit p3.0;P3.0控制最右邊的數碼管
led_2 bit p3.1;P3.1控制中間的數碼管
led_3 bit p3.7;P3.7控制最左邊的數碼管

;(原理圖標的好象有出入,以PCB為準,最左邊的數碼管是顛反安裝的)

HA BIT P3.2;接蜂鳴器
key_f bit p3.3;接按鈕公共端

pnp1 bit p3.4;T1路控制輸出
pnp2 bit p3.5;T2路控制輸出

timer_50ms bit 00h;定時50毫秒標志位
timer_1s bit 01h;定時1秒標志位
timer_3s bit 03h;定時3秒標志位
; timer_20s bit 04h;定時20秒標志位
timer_1min bit 05h;定時1分鐘標志位
timer_10min bit 06h;定時10分鐘標志位

;timer_am bit 07h
key_set_f bit 08h
sec_flash_f bit key_set_f+1h
;*************************************************************
al1_f bit sec_flash_f+1h
al2_f bit al1_f+1h
al3_f bit al2_f+1h
flash_f bit al3_f+1h
set_f bit flash_f+1h
;*****************************************************************
al_f bit set_f+1h
al_out_f bit al_f+1h
all_s bit al_f+2h
turn_f bit all_s+1h

aal1_f bit turn_f+1h
aal2_f bit turn_f+2h
aal3_f bit turn_f+3h
;*****************************************************************

tih equ 3ch ;9e58h 6MHz
til equ 0b0h ;3cb0h 12MHz
tis equ 10d ;20d 12MHz, 10d 6MHz
ti_no equ 3h

led_blk equ 0ah
led_c equ 0bh
led_e equ 0ch

;主程序開始
oRG 0000H; ;
sJMP start
ORG 0003H; ;
reti;
ORG 000BH ;
reti ;
ORG 0013H
reti ;
ORG 001BH ;
aJMP T1 ;
ORG 0023H ;
RETI; AJMP RS_485 ;
;**************************************
start:

MOV R7,#78h ;
MOV R0,#10H ;
CLR A ;
CR: INC R0 ;
MOV @R0,A ;
djnz r7,cr ;將內存清零
MOV SP,#40H ;
clr ea
clr set_f
clr turn_f
setb pnp2
setb pnp1
;********************************* j al1-3 data
mov r0,#al1_min
mov r1,#al1_min_t
mov r7,#07h
op_4:
mov a,@r0
cjne a,#19d ,op_1
op_2: mov a,#00h
mov @r0,a
sjmp op_3
op_1:
jnc op_2

op_3:
mov a,@r0
mov @r1,a
inc r0
inc r1
djnz r7 ,op_4

mov a,flash
mov c,acc.1 ;acc.1 al1 acc.2 al2 ....
mov al1_f,c
mov c,acc.2 ;acc.1 al1 acc.2 al2 ....
mov al2_f,c
mov c,acc.3 ;acc.1 al1 acc.2 al2 ....
mov al3_f,c

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

;************** INT_CTRL

; SETB ie0 ;
; SETB EX0 ;
; SETb ex1 ;
setB ET0 ;
SETB ET1 ;
; SETB IT0 ;
; setb IT1 ;
MOV TMOD,#00010001b ;
MOV TH1,#tih
mov tl1,#til
mov th0,#00h
mov tl0,#00h

;***********RS_CTRL

; MOV SCON,#00H ;

;*****************
; MINI_Pragram
;*****************
mov timers,#tis
mov sec,#00d
;mov al1_hour_t ,al1_hour
;mov al1_min_t ,al1_min

;mov al2_hour_t ,al2_hour
;mov al2_min_t ,al2_min

;mov al3_min_t ,al3_min
;mov al3_hour_t,al3_hour

mov timer_no,#ti_no
mov del4,#00h
;mov beep_timer,#8d

mov del1,#00d
mov del2,#00d
mov del3,#00d
mov del4,#00d
mov key_power,#01d

setb al_out_f
setb tr1
setb ea

setb timer_50ms

STAR_BI:
; setb flash_f
acall led_jmp_1;led_times
aCALL KEY_1
acall al_out_way
acall delay
sjmp star_bi
;;;;;;;;;;;;;;;;;
delay:

inc del3
mov a,del3
cjne a,#0ffh,del_1
mov del3,#00h
inc del4
mov a,del4
cjne a,#040h,del_1
mov del4,#00h
clr flash_f
clr set_f

del_1:

ret

;****************************
; key_pragm
;****************************

KEY_1:
mov p1,#00h
mov p3,#0ffh
clr key_f
mov a,p3
setb key_f
anl a ,#10000011b
cjne a,#10000011b,you_key_1
key_e:

mov p3,#0ffh
setb key_f
mov key_data,#00h

key_1_end:

ret

you_key_1:
mov del3,#0feh
mov del4,#0feh

setb key_f

mov b,#20h
lll_1:
push b
lcall led
pop b
djnz b ,lll_1

mov p1,#00h
mov p3,#0ffh
clr key_f
mov a,p3
setb key_f
anl a ,#10000011b
cjne a,#10000011b,you_key_2

sjmp key_e

you_key_2: jb acc.0 ,key_set

mov key_data,#01h
sjmp you_key_33

key_set: jb acc.1 ,you_key_3

mov key_data,#02h
sjmp you_key_33

you_key_3:
jb acc.7 ,you_key_33
mov key_data,#03h
sjmp you_key_33

you_key_33:

setb key_f
acall led

inc del1
mov a,del1
cjne a,#0ffh ,jhg_1
mov del1,#00h

inc del2
mov a,del2
cjne a,#08h ,jhg_1
mov del2,#00h
setb flash_f
setb set_f
; mov key_power,#01h
; mov key_data,#00h

jhg_1:
mov p1,#00h
mov p3,#0ffh

clr key_f
mov a,p3
anl a ,#10000011b
cjne a,#10000011b,you_key_33
setb key_f
mov p3,#0ffh
mov del1,#00h
mov del2,#00h

; acall beep
mov r6,#040h
bb_1:
;!!!!!!!!!!!!!!!!!!!!!!!!!!
clr ha
setb key_f
acall led
acall led
djnz r6 ,bb_1
setb ha
;******************************************
mov dptr,#key_ord_1
mov a,key_data
mov b,#03h;!!!!!!!!!!!!!!!
mul ab
jmp @a+dptr

key_ord_1: ljmp key_k0_0
ljmp key_k1_0
ljmp key_k2_0
ljmp key_k3_0

key_k0_0: ;no key
ajmp key_1_end

key_k1_0: ; key_3
acall key_3
ajmp key_1_end

key_k2_0: ; key_2
acall key_2
ajmp key_1_end

key_k3_0: ; key_1

inc key_power
mov a,key_power
cjne a,#08h ,io_1

mov key_power,#01h
io_1:
ajmp key_1_end

;**************************************
proc key_3
key_3:

mov dptr,#led_ord_3
mov a,key_power ;data
mov b,#02h
mul ab
jmp @a+dptr

led_ord_3: ajmp led_k0_2
ajmp led_k2_2
ajmp led_k1_2
ajmp led_k4_2
ajmp led_k3_2
ajmp led_k6_2
ajmp led_k5_2
ajmp led_k7_2

led_k0_2: ; nop

ajmp led_jmp_5_end

led_k1_2: ; al1 way off/on

cpl al1_f
jb flash_f ,tw_11

sjmp tw_21
tw_11:
mov c,al1_f
mov a,flash
mov acc.1 ,c
mov flash,a

tw_21:
ajmp led_jmp_5_end

led_k2_2: ;al1 timer

jb flash_f ,set_11
inc al1_min_t
mov a,al1_min_t
cjne a,#60 ,set_12
mov al1_min_t,#00h
set_12:
sjmp set_14

set_11:
inc al1_min
mov a,al1_min
cjne a,#60 ,set_14
mov al1_min,#00h
set_14:

ajmp led_jmp_5_end

led_k3_2: ;al2 way off/on

cpl al2_f
jb flash_f ,tw_12
sjmp tw_22
tw_12:
mov c,al2_f
mov a,flash
mov acc.2 ,c
mov flash,a

tw_22:
ajmp led_jmp_5_end

led_k4_2: ;al2 timer

jb flash_f ,set_21
inc al2_min_t
mov a,al2_min_t
cjne a,#60 ,set_22
mov al2_min_t,#00h
set_22:
sjmp set_24

set_21:
inc al2_min
mov a,al2_min
cjne a,#60 ,set_24
mov al2_min,#00h
set_24:

ajmp led_jmp_5_end

led_k5_2: ; al3 way off/on

cpl al3_f
jb flash_f ,tw_13
sjmp tw_23
tw_13:
mov c,al3_f
mov a,flash
mov acc.3 ,c
mov flash,a

tw_23:
ajmp led_jmp_5_end

led_k6_2: ;al3 timer
jb flash_f ,set_31
inc al3_min_t
mov a,al3_min_t
cjne a,#60 ,set_32
mov al3_min_t,#00h
set_32:
sjmp set_34

set_31:
inc al3_min
mov a,al3_min
cjne a,#60 ,set_34
mov al3_min,#00h
set_34:
ajmp led_jmp_5_end

led_k7_2: ; turn off/on
setb turn_f

led_jmp_5_end:
ret
end
;****************************************
proc key_2
key_2:

ajmp led_jmp_5_end

led_k1_2: ; al1 way off/on

ajmp led_jmp_5_end

led_k2_2: ;al1 timer
jb flash_f ,set_311
inc al1_hour_t
mov a,al1_hour_t
cjne a,#20d ,set_321
mov al1_hour_t,#00h
set_321:
sjmp set_341

set_311:
inc al1_hour
mov a,al1_hour
cjne a,#20d ,set_341
mov al1_hour,#00h
set_341:

ajmp led_jmp_5_end

led_k3_2: ;al2 way off/on
ajmp led_jmp_5_end

led_k4_2: ;al2 timer
jb flash_f ,set_312
inc al2_hour_t
mov a,al2_hour_t
cjne a,#20d ,set_322
mov al2_hour_t,#00h
set_322:
sjmp set_342

set_312:
inc al2_hour
mov a,al2_hour
cjne a,#20d ,set_342
mov al2_hour,#00h
set_342:

ajmp led_jmp_5_end

led_k5_2: ; al3 way off/on
ajmp led_jmp_5_end

led_k6_2: ;al3 timer
jb flash_f ,set_313
inc al3_hour_t
mov a,al3_hour_t
cjne a,#20d ,set_323
mov al3_hour_t,#00h
set_323:
sjmp set_343

set_313:
inc al3_hour
mov a,al3_hour
cjne a,#20d ,set_343
mov al3_hour,#00h
set_343:

ajmp led_jmp_5_end

led_k7_2: ; turn off/on

led_jmp_5_end:
ret
end

;******************************************** led
proc led_jmp_1
led_jmp_1:

led_k1_2: ; al1 way off/on

mov led1 ,#0bh

jnb al1_f,aal_1

mov a,#0ch
mov led1,a
aal_1:
mov led3,#1d
mov led2,#led_blk

ajmp led_jmp_5_end

led_k2_2: ;al1 timer

jb flash_f ,led_m11
mov a,al1_min_t
mov r7,al1_hour_t
sjmp led_m21
led_m11:
mov a,al1_min
mov r7,al1_hour
led_m21:
acall timer_led1
ajmp led_jmp_5_end

led_k3_2: ;al2 way off/on
mov led1 ,#0bh

jnb al2_f,aal_2

mov a,#0ch
mov led1 ,a

aal_2:
mov led3,#2d
mov led2,#led_blk

ajmp led_jmp_5_end

led_k4_2: ;al2 timer

jb flash_f ,led_m12
mov a,al2_min_t
mov r7,al2_hour_t
sjmp led_m22
led_m12:
mov a,al2_min
mov r7,al2_hour
led_m22:
acall timer_led1

ajmp led_jmp_5_end

led_k5_2: ; al3 way off/on

mov led1 ,#0bh

jnb al3_f,aal_3

mov a,#0ch
mov led1 ,a

aal_3:
mov led3,#3d
mov led2,#led_blk
ajmp led_jmp_5_end

led_k6_2: ;al3 timer

jb flash_f ,led_m13
mov a,al3_min_t
mov r7,al3_hour_t
sjmp led_m23
led_m13:
mov a,al3_min
mov r7,al3_hour
led_m23:
acall timer_led1
ajmp led_jmp_5_end

led_k7_2: ; turn off/on
mov led3,#00h
mov led2,#0bh;led_b
mov led1,#0bh;led_b

led_jmp_5_end:
acall led
ret
end

timer_led1:

;*******************************min to led
MOV B,#10D
DIV AB
mov led2,a
mov a,b
mov led1,a
;*******************************hour to led
mov a,r7
MOV B,#10D
DIV AB
mov r1,a
mov a,b
mov b,r1
mov r1,a

jnz tt_2

tt_1: mov a,#led_blk
tt_2:
mov led3,a
clr all_s

mov a,b
jz tt_3
setb all_s
mov led3 ,r1
tt_3:
ret

;********************
; LED_PROGRAM
;*******************

LED:

mov c,flash_f
jnc ffl_1
mov c,timer_50ms
jc ffl_1

;mov led1,#led_blk
;mov led2,#led_blk
;mov led3,#led_blk
ajmp led_end

ffl_1:

mov dptr,#led_asc
;***************************led1
mov a,led1
movc a,@a+dptr
mov c, timer_50ms
mov acc.0,c

mov p1,a

clr led_1

acall timer_1ms

setb led_1
;*************************led2
led_led2:

mov a,led2
movc a,@a+dptr
mov p1,a

clr led_2
acall timer_1ms
setb led_2
;*************************led3
led_led3:
mov a,led3
movc a,@a+dptr
mov c,all_s
mov acc.0 ,c

mov p1,a

clr led_3
acall timer_1ms
setb led_3
;*************************
led_end:
mov p1,#0ffh
mov a,p3
orl a,#11111000b
mov p3,a

ret

led_asc:
db 11101110B;0 "bafgecdh"
db 10000100B;1
db 11011010B;2
db 11010110B;3
db 10110100B;4
db 01110110B;5
db 01111110B;6
db 11000100B;7
db 11111110B;8
db 11110110B;9
DB 00000000B;BLACK=>0aH
DB 01111000B;f=>b
dB 11101100B;e=>C
DB 00110000B;1,=>D

;**********************************
;delay
;********************************

timer_1ms:
push b
mov r2,#01h
a_1: mov b,#020h
b_1: djnz b,b_1
djnz r2,a_1
pop b
ret

;******************
; TO-T1_INT T1定時器完成100毫秒定時(6M晶振)
;******************

T1:
setb tr0
PUSH ACC ;程序參數保護
PUSH b ;
push psw

inc time_led1
mov a,time_led1
cjne a,#5d,t1_n1;判斷time_led1中是否滿5?
mov time_led1,#00h
cpl timer_50ms;滿50毫秒后對50毫秒標志位取反

; mov a,timers
; cjne a,#10d ,t1_n11;判斷timers中是否滿10?
;t1_n12:
; clr timer_1s;滿1秒后對1秒標志位取反

sjmp t1_n1
;*********************************
t1_end_2: ajmp t1_end_1
;********************************

;t1_n11: jc t1_n12
; setb timer_1s

t1_n1: djnz timers ,t1_end_2
mov timers,#tis

inc time_led3
mov a,time_led3
cjne a,#03d,t1_sec
mov time_led3,#00h
cpl timer_3s
t1_sec:
inc sec
mov a,sec
cjne a,#60d ,t1_end
mov sec,#00d

jnb al1_f ,t1_al1

mov a,al1_min_t
mov b,al1_hour_t
mov c ,aal1_f
acall al_all
mov al1_min_t,a
mov al1_hour_t,b
mov aal1_f,c

t1_al1:
jnb al2_f ,t1_al2
mov a,al2_min_t
mov b,al2_hour_t
mov c ,aal2_f
acall al_all
mov al2_min_t,a
mov al2_hour_t,b
mov aal2_f,c

t1_al2:
jnb al3_f ,t1_al3
mov a,al3_min_t
mov b,al3_hour_t
mov c ,aal3_f
acall al_all
mov al3_min_t,a
mov al3_hour_t,b
mov aal3_f,c

t1_al3:
T1_END:
t1_end_1:
;************************************ sub t0 timer
clr c
clr tr0
mov b,timer_no
mov a,#til
add a,tl0

addc a,b ;*******have 5 order
mov tl1 ,a

mov a,#tih
addc a, th0
mov th1,a
mov th0,#00h
mov tl0,#00h
setb tr1
pop psw
pop b ;
pop acc ;
RETI ;

;************************************
beep:
clr ha

mov r6,#060h
bee_2: mov r4,#0ffh
bee_1:
djnz r4 ,bee_1
djnz r6,bee_2
setb ha
ret
;***************************************
stop:
mov a,#0ffh
mov p1,a
mov p3,a

mov a,pcon
orl a,#00000010b
mov pcon,a
ret

al_out_way:

jnb aal1_f ,al_out1

mov r3,#0ffh
pnp_3:
mov b,#060h

pnp_4:
push b

acall led_jmp_1;led_times

mov c,timer_50ms
mov ha ,c
pop b
djnz b ,pnp_4
djnz r3 ,pnp_3

mov c,al2_f
orl c,al3_f
jc al_out54
acall stop

al_out54:
clr aal1_f
clr al1_f
sjmp al_out4

al_out1:
jnb aal2_f ,al_out2

clr pnp1
mov r3,#0ffh
pnp_1:
mov b,#020h

pnp_2:
push b

acall led_jmp_1;led_times
pop b
djnz b ,pnp_2
djnz r3 ,pnp_1

setb pnp1

mov c,al1_f
orl c,al3_f
jc al_out64
acall stop

al_out64:
clr aal2_f
clr al2_f
sjmp al_out4

al_out2:
jnb aal3_f ,al_out3
clr pnp2

al_out3:
jnb turn_f ,al_out4
acall stop
al_out4:
ret
;*******************************************
al_all:
jc al_all_1
dec a
jnz al_all_1
mov a,b
jz al_all_3
dec b
sjmp al_all_2

al_all_3:
setb c
sjmp al_all_1

al_all_2:
mov a,#60d
al_all_1:

ret

;看懂別人寫的匯編程序是很困難的事情,我希望有興趣的網友能幫我完成這段程序的中文注釋,這樣可以使初學者能夠更加容易學會編程.

這是上面程序匯編以后獲得的編程器燒寫文件:timer.rar