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;HC11 PWM Motor Control Example
;Demonstrates ADC and Timer Output Capture functions
PORTA equ $1000
PORTC equ $1003
PORTB equ $1004
DDRC equ $1007
TOC1 equ $1016
TOC2 equ $1018
TCTL1 equ $1020
TCTL2 equ $1021
TMSK1 equ $1022
TFLG1 equ $1023
TMSK2 equ $1024
PACTL equ $1026
ADCTL equ $1030
ADR1 equ $1031
ADR2 equ $1032
org $F000
start: lds #$FF
ldaa #$FF ;Port C is output
staa DDRC
ldaa #$80 ;Enable OC1 interrupts.
staa TMSK1 ;
ldaa #$2 ;Set the prescaler (divide by 16)
staa TMSK2
ldaa #$80 ;Enable PA7 as output
staa PACTL
ldaa #$10 ;Start first ADC conversion - multi mode enable
staa ADCTL
ldd #$0100 ;Load the capture register
std TOC1
cli ;Enable interupts
loop wai
bra loop
;OC1 interrupt service
oc1f ldaa #$10 ;Start another ADC conversion
staa ADCTL
ldaa ADR1 ;Read the pot position from ADC channel 1
staa PORTB ;Display it
suba #127 ;0x7F is zero reference.
bne oc1f_ne ;Jump if values not same
;Set Both outputs low. Motor is stationary
clrb
stab PORTA ;Both OC1 and OC2 outputs low
stab TCTL1 ;TOC2 mode is disabled
bra done
;Non-zero drive - decide if +ve or -ve:
oc1f_ne bcs oc1f_cs
;Positive result - motor spins clockwise:
ldab #$40 ;Port A drives this value:
stab PORTA
clrb ;Release TOC2 latch - Port A acquires value, above.
stab TCTL1
ldab #$40 ;TOC 2 output toggles on OC2 event; motor drive stops.
stab TCTL1
bra done
;Negative result - motor spins anti-clockwise:
oc1f_cs ldab #$80 ;Port A drives this value:
stab PORTA
clrb ;Release TOC2 latch - Port A acquires value, above.
stab TCTL1
ldab #$40 ;TOC 2 output toggles on OC2 event; motor drive stops.
stab TCTL1
nega ;Invert result -> 0xFF -> 0x01 etc.
;Now set up TOC2 to trigger at a time forward of TOC1. This means that the motor will
;be powered for the number of ticks in ACCA * 256.
done: tab ;TOC 2 is set to trigger after this no of cycles.
clra
rolb
rola
rolb
rola
rolb
rola
rolb
rola
rolb
rola
addd TOC1
std TOC2
ldd #$1000
addd TOC1
std TOC1
ldaa #$80 ;Clear the TOC 1 interrupt
staa TFLG1
rti
;Interrupt Vectors
org $FFE8
dw oc1f
org $FFFE
dw start
4 vợ + 10 con + 5 bồ bịch
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