2.3 Relaxatie-oscillator

; EXTI1->(sens_stamp): 0013h (interrupt vector for saving pos. of timer0)
; (jmps to sens_stamp)
; TIMER1 001bh (interrupt vector for overflow in timer1)
; (process: carry timer overflow to OP_1)
;************************* functions ***********************************
; main: (main program starts here)
; initsys: (initializes system: ports, interrupts, variables)
; sett0_cnt: (initializes timer0 for counting)
; sett1_cnt: (initializes timer1 for counting)
; sett1_midi: (initializes timer1 for midi)
; calc_t0: (calculates setup timer values for signal)
; calib: (loads prd with proper values)
; freqcap: (measures frequency on _int0
; wavectrl(wvmem): (processes generated waveform)
; sens_stamp(tmp_TH0,tmp_TL0) (stamps position of TH0 and TL0, when sensor)
; Mul_16( (OP_0..3) * (R2,R3) ) (Performs multiply between long and int)
; Div_16( (OP_0..3) / (R2,R3) ) (Performs division between long and int)
;************************* constants ***********************************
clk equ 12000 ;system clock in kHz
baud equ 31250 ;bits/s on midi output
sigpw equ 35 ;pulsewidth of lo state in µsec
ccpins equ 12 ;#clockcycles per instruction
proc_tm equ 20 ;est. processing time, interrupt routine
num_per equ 10 ;#periods to calculate average
shift_wv equ 25 ;force sensor to run in phase with wave (in µsec)
sens_tm equ 46 ;sensor reaction is valid during 42% of hi-wave
sensctrl bit P1.0 ;output port, controls sensor
sensor bit P3.2 ;input port, sensor feed back signal
midictrl equ 0d0h ;coding for general aftertouch with midi
;************************** variables ***********************************
wvmem equ 20h.0 ;bit adres for hi or lo state of output signal
vldsns equ 20h.1 ;bit adres for valid sensor measurement (1=valid)
np_flag equ 20h.2 ;flag for avialability of enough data from int. routine
tmp_C equ 20h.3 ;flag for temporary storing Carry
tmp_A equ 43h ;register is faster than stack
prd_h equ 44h ;target period MSB in timer counting rate
prd_l equ 45h ;target period LSB in timer counting rate
lo_TH0 equ 46h ;duration lo state MSB timer0
lo_TL0 equ 47h ;duration lo state LSB timer0
hi_TH0 equ 48h ;duration hi state MSB timer0
hi_TL0 equ 49h ;duration hi state LSB timer0
hivdTH0 equ 4ah ;duration hi state, during which sensor may respond
hivdTL0 equ 4bh ;duration hi state, during which sensor may respond
OP_0 equ 4ch ;Operand1 (Highest byte unsigned long)
OP_1 equ 4dh ;
OP_2 equ 4eh ;
OP_3 equ 4fh ;
;R2 ;Operand2 (Highest byte unsigned ‘long’
;R3 ;functions implement uptill now only int size
TMP_0 equ 50h ;Highest byte unsigned long
TMP_1 equ 51h ;
TMP_2 equ 52h ;
TMP_3 equ 53h ;
tmp_TH0 equ 54h ;memory for position of TH0
tmp_TL0 equ 55h ;memory for position of TL0
wndwTH0 equ 56h ;size of valid window where sensor may respond
wndwTL0 equ 57h ;size of valid window where sensor may respond
case equ 58h ;task dispatcher in main
midival equ 59h ;pressure (0..127) into control midivalue
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