Holtek HT-IDE, User Manual, Page: 227 / 258

jmp hour_inc ;no. test again
call inc_hour ;yes. hour+1
clr second ;second=0
clr tmr0c.4 ;stop timer0
mov a,0b0h ;(5) ;reload timer0 counter
mov tmr0l,a ;
mov a,3ch ;(0.5 second)
mov tmr0h,a ;
set tmr0c.4 ;restart timer0
ret ;
show_clock endp ;
;------------------------------------------------------------
org 0f00h ;mask data
dc 10h,20h,40h,80h
;------------------------------------------------------------
delays proc ;
mov a,7fh ;load counter
mov count1,a ;
d2: ;
sdz count1 ;count down count1
jmp d2 ;
ret ;
delays endp ;
;------------------------------------------------------------
inc_hour proc ;
mov a,hourh ;
sub a,02h ;
sz acc ;if over 20 hours
jmp h_201 ;no. goto h_201
inc hourl ;yes. hourl+1
mov a,hourl ;
sub a,04h ;
sz acc ;if over 24 hours?
ret ;no. return
clr hourl ;yes. hourl=0
clr hourh ; hourh=0
ret ;return
h_201: ;
inc hourl ;hourl+1
mov a,hourl ;
sub a,0ah ;
sz acc ;if over 10 hours?
ret ;no. return
clr hourl ;yes. hourl=0
inc hourh ; hourh=0
ret ;
inc_hour endp ;
;------------------------------------------------------------
inc_min proc ;
Chapter 16 Interrupt and timer applications
217