Dear Alex
this code is very clumsy but it work for my 5 digits count up and down project
;chöông trình coil.asm ñeå vaän haønh moät maùy quaán daây, nhaäp soá voøng daây caàn quaán
;sau ñoù maùy seõ ngöøng khi soá voøng ñaõ ñuû
;
$mod52
;taäp hôïp caùc maõ display töø 0 ñeán 9

zero equ 00000010b ;maõ mask cuûa caùc soá töø 0 ñeán 9
mot equ 01011110b ;
hai equ 00101000b
ba equ 01001000b
bon equ 01010100b
nam equ 01000001b
sau equ 00000001b
bay equ 01011010b
tam equ 00000000b
chin equ 01000000b

;taäp hôïp caùc chaân led drive

don_vi bit p3.5
chuc bit p3.4
tram bit p3.1
ngan bit p3.0
chuc_ngan bit p3.7
;thoâng tin veà trò soá ñeám chöùa vaøo caùc register ni
unit equ 35h
ten equ 36h
hundred equ 37h
thousand equ 38h
ten_thousand equ 39h
count1 equ 40h
count2 equ 41h
count3 equ 42h
count4 equ 43h
count5 equ 44h
led_out equ p1
;===============================================================

org 00h ;vectô reset
ljmp start ;nhaåy tôùi start
org 03h ;external0 interrupt
ljmp count_up ; nhaåy tôùi isr cuûa count_up
org 0bh ;timer 0 interrupt
ljmp update
org 13h ;external1 interrupt
ljmp count_down
org 50h ;locate beginning of rest of program

;=================================================================
init_baud:
mov psw,#00h
mov tmod, #00100001b ;ñaët timer0 chaïy 8 bit auto reload
setb ea
setb et0
setb tr0
setb it0
setb it1
setb ex0
setb ex1
ret

update:
mov th0, #-50 ; ñaët trò cho caùc timer reg
mov tl0, #-50 ; ñeå taïo khoaûng ñeám 1/100 giaây
mov unit,count1
lcall display_don_vi
mov ten,count2
lcall display_chuc
mov hundred,count3
lcall display_tram
mov thousand,count4
lcall display_ngan
mov ten_thousand,count5
lcall display_10ngan
reti

;
count_up:
push acc
push psw
clr ex1
mov a,count1
add a,#01h
da a
mov count1,a
cjne a,#10h,xong_isr
mov count1,#00h
mov a,count2
add a,#01h
da a
mov count2,a
cjne a,#10h,xong_isr
mov count2,#00h
mov a,count3
add a,#01h
da a
mov count3,a
cjne a,#10h,xong_isr
mov count3,#00h
mov a,count4
add a,#01h
da a
mov count4,a
cjne a,#10h,xong_isr
mov count4,#00h
mov a,count5
add a,#01h
da a
mov count5,a
cjne a,#10h,xong_isr
mov count5,#00h

xong_isr:
setb ex1
pop psw
pop acc ; traû laïi cho a
reti

count_down:
push acc
push psw
clr ex0
mov a,count1
dec a
mov count1,a
cjne a,#-1,exit_count
mov count1,#9
mov a,count2
dec a
mov count2,a
cjne a,#-1,exit_count
mov count2,#9
mov a,count3
dec a
mov count3,a
cjne a,#-1,exit_count
mov count3,#9
mov a,count4
dec a
mov count4,a
cjne a,#-1,exit_count
mov count4,#9
mov a,count5
dec a
mov count5,a
cjne a,#-1,exit_count
mov count5,#9
exit_count:
setb ex0
pop psw
pop acc
reti


delayms: ;loop delay 1/1000 sec
mov r4,#00h
loopa:
inc r4
mov a,r4
cjne a,#0ffh,loopa
ret

;**************************************************************************
; caùc c/t con tí töø display_0 tôùi display_9 thöïc ra laø caùc mask cuûa ñeøn led 7 ñoaïn
;vôùi key_port.7 veà phiaù traùi vaø key_port.0 beân phaûi,key_port.7 luoân off vì chæ duøng 7 bit thoâi.
;**************************************************************************
display_0:
mov led_out, #zero
ret

display_1:
mov led_out, #mot
ret

display_2:
mov led_out, #hai
ret

display_3:
mov led_out, #ba
ret

display_4:
mov led_out, #bon
ret

display_5:
mov led_out, #nam
ret

display_6:
mov led_out, #sau
ret

display_7:
mov led_out, #bay
ret

display_8:
mov led_out, #tam
ret

display_9:
mov led_out, #chin
ret

; caùi get number ni kieám soá caàn display vaø maàn luoân
; ñoïc data töø msb cuûa acc ñeå bieát soá naøo caàn display

get_number:
cjne a, #00h, so1 ; jump if not 0
acall display_0
ret
so1:
cjne a, #01h, so2 ; jump if not 1
acall display_1
ret
so2:
cjne a, #02h, so3 ; jump if not 2
acall display_2
ret
so3:
cjne a, #03h, so4 ; jump if not 3
acall display_3
ret
so4:
cjne a, #04h, so5 ; jump if not 4
acall display_4
ret
so5:
cjne a, #05h, so6 ; jump if not 5
acall display_5
ret
so6:
cjne a, #06h,so7 ; jump if not 6
acall display_6
ret
so7:
cjne a, #07h, so8 ; jump if not 7
acall display_7
ret
so8:
cjne a, #08h, so9 ; jump if not 8
acall display_8
ret
so9:
acall display_9 ; laø 9 chöù ñaâu nöõa
ret
;********* display thousand digit *********************************
display_10ngan:
mov led_out,#0ffh
mov a, ten_thousand ; move hundreds into a (for get_number routine)
anl a, #00fh
acall get_number
clr chuc_ngan ; turn on 5th digit
lcall delayms
setb chuc_ngan
ret

;********* display thousand digit *********************************
display_ngan:
mov led_out,#0ffh
mov a, thousand ; move hundreds into a (for get_number routine)
anl a, #00fh
acall get_number
clr ngan ; turn on 4th digit
lcall delayms
setb ngan
ret

;********* display hundred digit ******************************
display_tram:
mov led_out,#0ffh
mov a, hundred ; move hundreds into a (for get_number routine)
anl a, #00fh
acall get_number
clr tram ; turn on 3rd digit
lcall delayms
setb tram
ret
;******** display ten digit ***********************************
display_chuc:
mov led_out,#0ffh
mov a,ten
anl a, #00fh
acall get_number
clr chuc
lcall delayms
setb chuc
ret
;*********display unit digit ****************************
display_don_vi:
mov led_out,#0ffh
mov a,unit
anl a, #00fh
acall get_number
clr don_vi
lcall delayms
setb don_vi
ret

;========================================================
start:
lcall init_baud
mov r0,#00h
mov count1,#0
mov count2,#0
mov count3,#0
mov count4,#0
mov count5,#0
ret
end

have a good day
Vu Nhu Khanh