2.3 Relaxatie-oscillator

setb TR0 ;1 timer 0 runs, but enough time till int. comes
jb np_flag,ti_nnow ;2 if main is processing data, skip summing
mov tmp_A,A
mov tmp_C,C
mov A,OP_3 ;now enough time to perform 24 bits addition
add A,tmp_TL0 ;LSB
mov OP_3,A
mov A,OP_2
addc A,tmp_TH0 ;MSB
mov OP_2,A
jnc ti_fmty ;if there is no carry, routine is ready
inc OP_1 ;I say: 24 bits is really enough!
ti_fmty: djnz R3,ti_reta ;decrease counter for #num_per, jmp if not zero
setb np_flag ;flag to tell main interrupt routine is ready
ti_reta: mov C,tmp_C
mov A,tmp_A
ti_nnow: reti
;**** part I **** wvmem:=lo, vldsns no change ****
;put sensctrl and flag wvmem in low state, disable EX1 (no _int1), set timer0
ti_dolo: clr wvmem ;1 flag of sensctrl
clr sensctrl ;1 sensctrl goes lo
mov TH0,lo_TH0 ;2 timer 0 hi-byte
mov TL0,lo_TL0 ;2 timer 0 lo-byte
setb TR0 ;1 timer 0 runs
clr EX1 ;1 no _int1 allowed during lo state
reti
;*******************************************************************************
;* sens_stamp -> (from EXTI1) TH0, TL0 *
;* interrupt from _int1 occurred, so there’s some work to do. Sensor produced *
;* an transistion from hi to lo, so it’s position where that happened, rela- *
;* ted to the pos. of timer0, generating a control signal, must be stamped. *
;* (OP_0..3) * (R2,R3) *
;* *
;* Performs a multiply between a 32 and a 16 bit integer *
;* *
;*