ENGR270 LAB5 EXP2

    list    p=18F1220
    radix   hex
    config  WDT=OFF, LVP=OFF, OSC=INTIO2;   Disable WDT, Low V Prog and RA6 as a clock

#include    p18f1220.inc    ;Header file for SFR definitions

    count   equ     0x80

    org     0x00
    GOTO    StartL      ;Executes after reset

    org     0x08        ;High priority
    GOTO    HIPRIO

    org     0x20        ;Start the code

HIPRIO:
    BTFSC   PIR1, TMR1IF
    BRA     pwm20      ;If timer1 is interrupting then go to timer1 service routine
    BTFSC   INTCON, TMR0IF
    BRA	    pwm50
    RETFIE

pwm50:
    BCF	    T0CON, TMR0ON   ;disable tmr0

    INCF    count
    BZ	    Done

    MOVLW   .50
    MOVWF   CCP1CON
    BCF	    INTCON, TMR0IF  ;clear tmr0 interrupt flag
    BSF	    T1CON, TMR1ON   ;enable tmr1
    RETFIE

pwm20:
    BCF     T1CON, TMR1ON   ;disable timer1

	BTG		PORTB,3			;toggle motor direction
    MOVLW   .20
    MOVWF   CCP1CON
    BCF	    PIR1, TMR1IF    ;clear tmr1 interrupt flag
    BSF	    T0CON, TMR0ON   ;enable tmr0
    RETFIE


StartL:     ;entry point from reset
    ;Initialize all I/O ports
    CLRF    PORTA
    CLRF    PORTB
    MOVLW   0x7F
    MOVWF   ADCON1
    MOVLW   0x0D
    MOVWF   TRISA
    MOVLW   0xC7
    MOVWF   TRISB
    ;Timer1 Initialization + interrupt enable/disable
    BSF     INTCON, PEIE        ;enable peripheral interrupts
    BSF     PIE1,   TMR1IE      ;enable timer1 interrupt
    BSF     IPR1,   TMR1IP	;set timer1 priority to high
    BCF	    PIR1,   TMR1IF	;clear tmr1 flag
    BSF	    INTCON, TMR0IE	;enable tmr0 interrupt
    BSF	    INTCON2,TMR0IP	;enable tmr0 priority to high
    BCF	    INTCON, TMR0IF	;clear tmr0 flag
    MOVLW   0x58		;Timer 1: "&&&-bit, osc. clock, 1:2 prescale, enabled, internal clk"
    MOVWF   T1CON
    MOVLW   0x00
    MOVWF   T0CON
    ;Set timer 1 so next timer interrupt is in approx 5 seconds
    MOVLW   0xB3
    MOVWF   TMR1H
    MOVWF   TMR0H
    MOVLW   0xB5
    MOVWF   TMR1L
    MOVWF   TMR0L

    BSF     T0CON, TMR0ON       ;Enable timer0
    BSF     INTCON, GIE		;Enable interrupts globally

    ;Following steps setup PWM
    MOVLW   0x00C           ;"0000 1100
    MOVWF   CCP1CON         ;PWM output on P1A Pin18

    CLRF    TMR2            ;Timer2 register
    MOVLW   0x05            ;Enable timer and set prescale to 4
    MOVWF   T2CON
    BCF     PIR1, TMR2IF    ;clear timer2 flag

    MOVLW   .99
    MOVWF   PR2

    MOVLW   .50
    MOVWF   CCPR1L          ;Set power level to 50%

    MOVLW   .254
    MOVWF   count

WAITL:
    BTFSS   PIR1, TMR2IF
    BRA     WAITL
    BCF     TRISB,3         ;Set P1A/RB3/CCP1 as an output pin
    BSF     PORTB,5         ;turn on LED just to indicate EDbot is on

MainL:      ;waiting in a loop
    BRA     MainL

Done:

    end