倒計時器在生活非常有用，用單片機(jī)自制，不但電路簡單，而且功能可根據(jù)需要自行設(shè)計。由74系列、40系列小規(guī)模數(shù)字芯片設(shè)計的倒計時器非常多，但有顯示不直觀（無LED數(shù)碼管）；調(diào)整參數(shù)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(jī)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(shè)置啟動、關(guān)閉。
2． 范圍：0~20小時，可任意設(shè)定。關(guān)機(jī)后數(shù)據(jù)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(guān)機(jī)
二、工作原理
 
電路見上圖整機(jī)由89c2051、三位LED數(shù)碼管、K1-K4、R、T等元器件組成。89C2051內(nèi)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(zhuǎn)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(qū)動：蜂鳴器、PNP晶體管。LED數(shù)碼管采用共陰高亮型，LED1數(shù)碼管要旋轉(zhuǎn)180度。因為要顯示：“19：99”，而只有三位數(shù)碼管，因此用第三位的數(shù)碼管的小數(shù)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(jù)每路的啟動狀態(tài)，判別是否要減數(shù)。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(jìn)入掉電模式，電流<1.5uA，因此電路中無電源開關(guān)，再次啟動，由K4(復(fù)位鍵)完成。每路倒計數(shù)的初值、啟動狀態(tài)（是否開始倒計數(shù)），均可單獨設(shè)定并存在89c2015的RAM中，只要不斷電，數(shù)據(jù)不會改變。
四、操作說明
電路中設(shè)有K1~K4四個開關(guān)：
1．功能如下：
K1：定時路數(shù)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(tài)： 【F】表示：關(guān) �！緉】表示：開。再按下K1后，依此進(jìn)入第2路、3路的設(shè)置，最后進(jìn)入關(guān)機(jī)狀態(tài)。 LED顯示：【OFF】，K3按下則關(guān)機(jī)。
K2：小時位加1。當(dāng)超過9小時后，LED1的小數(shù)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(tài)切換【F-n-F】、關(guān)機(jī)確認(rèn)。
1、 當(dāng)LED數(shù)碼管顯示定時時間時，按下K3則相應(yīng)路數(shù)的分位加1。范圍：0~59分鐘。
2、 當(dāng)LED數(shù)碼管顯示【1.F】或【2.F】或【3F】時，按下K3則【F】變?yōu)椤緉】，再次按下K3則【n】變?yōu)椤綟】，一旦進(jìn)入【n】則相應(yīng)路數(shù)的倒計時就啟動。
3、 當(dāng)LED數(shù)碼管顯示【OFF】時，表示CPU已處于關(guān)機(jī)模式，只要按下K3，則CPU進(jìn)入掉電模式。
K4：復(fù)位 復(fù)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(tài)均可時時改變。
2．定時初值及啟動狀態(tài)的設(shè)定:
三路定時初值及啟動狀態(tài)均可一次設(shè)置好，方法如下：
1、K1~K3鍵任意鍵按下不松約5s后，LED數(shù)碼管顯示開始閃爍，表示已進(jìn)入初值和啟動狀態(tài)設(shè)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(tài)進(jìn)入設(shè)定。
四、注意事項
1、 當(dāng)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(hù)。
;***************
;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(jìn)行內(nèi)存分配*******************
led_1 bit p3.0;P3.0控制最右邊的數(shù)碼管
led_2 bit p3.1;P3.1控制中間的數(shù)碼管
led_3 bit p3.7;P3.7控制最左邊的數(shù)碼管 ;(原理圖標(biāo)的好象有出入,以PCB為準(zhǔn),最左邊的數(shù)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(biāo)志位
timer_1s bit 01h;定時1秒標(biāo)志位
timer_3s bit 03h;定時3秒標(biāo)志位
; timer_20s bit 04h;定時20秒標(biāo)志位
timer_1min bit 05h;定時1分鐘標(biāo)志位
timer_10min bit 06h;定時10分鐘標(biāo)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(nèi)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: 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 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: 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
setb flash_f
MOV a,#89d
MOV r7,#18d
acall timer_led1
clr flash_f
ajmp led_jmp_5_end 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(shù)保護(hù)
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(biāo)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(biāo)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(wǎng)友能幫我完成這段程序的中文注釋,這樣可以使初學(xué)者能夠更加容易學(xué)會編程. 這是上面程序匯編以后獲得的編程器燒寫文件：timer.hex 下載燒寫文件的方法：將鼠標(biāo)移到燒寫文件的超級鍵連處，點擊鼠標(biāo)的右鍵，選擇“目標(biāo)另存為（A）...”保存文件類型中不要選擇“文本文件”，應(yīng)該選擇“所有文件”，這樣就能獲得*.hex文件了。 |
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