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;KIT 102. SERVO-MOTOR DRIVER
dummy = 14h
flag = 15h
servo0 = rb.5
servo1 = rb.4
servo2 = rb.3
servo3 = rb.2
org 0
jmp start
org 4 ;Interrupt jumps here
clrb RTIF
setb flag.0
reti
start mov !ra, #255 ;Set ra to input.
mov !rb, #0 ;Set rb to output.
clr rb ;Clear port rb
mov dummy,#255
mov intcon, #0 ;Turn interrupts off.
mov adcon0,#AD_ctl ;Set AD clock and channel.
setb rp0 ;Enable register page 1.
mov adcon1,#AD_ref ;Set usable pins, Vref.
mov option,#00001000b ;WDT on, no prescale
clrb rp0 ;Back to register page 0.
setb adon ;Apply power to ADC.
setb go_done ;Start conversion.
not_done snb go_done ;Poll for 0 (done).
jmp not_done ;If 1, poll again.
mov counter2,adres ;Move ADC result into counter.
mov integer1,#3 ;Offset constant
mov integer2,#5 ;ADC multiplier
setb servo0 ;Output pulse to servo 0
call delay
clrb servo0
call pause ;ADC settling delay
clrb rp0 ;Ensure reg page 0
clrb chs1 ;Select channel 1
setb chs0 ; Ain 1
mov dummy,#255 ;Reload dummy variable
clrb adres ;Make sure
setb go_done ;Start conversion.
not_done1 snb go_done ;Poll for 0 (done).
jmp not_done1 ;If 1, poll again.
mov counter2,adres ;Move ADC result intocounter.
mov integer1,#3 ;Offset constant
mov integer2,#5 ;ADC multiplier
setb servo1 ;Output pulse to servo 1
call delay
clrb servo1
call pause
clrb rp0 ;Ensure reg page 0
setb chs1 ;Select channel 2
clrb chs0 ; Ain 2
mov dummy,#255
clr adres
setb go_done ;Start conversion.
not_done2 snb go_done ;Poll for 0 (done).
jmp not_done2 ;If 1, poll again.
mov counter2,adres ;Move ADC result into counter.
mov integer1,#3 ;Offset constant
mov integer2,#5 ;ADC multiplier
setb servo2 ;Output pulse to servo 2
call delay
clrb servo2
call pause
clrb rp0 ;Ensure reg page 0
setb chs1 ;Select channel 3
setb chs0 ; Ain 3
mov dummy,#255
clr adres
setb go_done ;Start conversion.
not_done3 snb go_done ;Poll for 0 (done).
jmp not_done3 ;If 1, poll again.
mov counter2,adres ;Move ADC result into counter.
mov integer1,#3 ;Offset constant
mov integer2,#5 ;ADC multiplier
setb servo3 ;Output pulse to servo 3
call delay
clrb servo3
sleep
jmp start ;Time out after 18 msec
; The number of loops this delay routine makes is dependent on the result of
; the AD conversion. The higher the voltage, the longer the delay.
delay clrb rp0 ;Page 0
mov intcon,#10100000b ;Enable RTCC interrupt
;****************** Fixed delay part of routine ****************
delay1 mov RTCC,#55 ;Fixed delay
wait1 jnb flag.0,wait1 ; of 200 till interrupt
clrb flag.0 ;Flag set on interrupt
djnz integer1,delay1 ;Three times through
;****************** Variable delay part of routine **************
sub dummy,counter2 ;RTCC counts UP!
load mov RTCC,dummy ;Load RTCC
wait2 jnb flag.0,wait2 ;Note infinite loop
clrb flag.0
djnz integer2,load ;Five times through
mov intcon,#0 ;Disable interrupt
ret
pause mov counter1,#120 ;Adds a short settling
settle djnz counter1,settle ; time to the ADC
ret
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