Lab4 ENGR270

;-------------------------------------------------------------------------------------
; FILE: IntrExample
; DESC: Interrupt Example - Demonstrates use of interrupts
; DATE: 5-18-16
; AUTH: Class
; DEVICE: PICmicro (PIC18F1220)
;-------------------------------------------------------------------------------------
 list p=18F1220 ; processor type
 radix hex ; default radix for data
 config WDT=OFF, LVP=OFF, OSC = INTIO2 ; Disable Watchdog timer, Low V. Prog, and RA6 as a clock

#include p18f1220.inc
#define countID 0x80
#define countOD 0x81

    org 0x000 ; Executes after reset

 GOTO StartL
    org 0x008 ; Executes after high priority interrupt

 GOTO HPRIO
    org 0x018 ; Executes after low priority interrupt

 GOTO LPRIO
    org 0x20

HPRIO: ; high priority interrupt
    ADDLW .2 ; when interrupt 0 occurs
    BCF INTCON, INT0IF ; Clear Interrupt 0
    BSF PORTB,3 ;Enable Left Motor
    BSF PORTB,4 ;Enable Right motor
    BCF PORTA,6 ;Backward Right
    BSF PORTA,7 ;Forward Left
    MOVLW .10
    CALL Delay
    BCF PORTB,3 ;Disable Left Motor
    BCF PORTB,4 ;Disable Right Motor
    RETFIE ; Return from interrupt


LPRIO: ; Low priority interrupt
    BTFSC INTCON3, INT1IF ; Check for Interrupt 1
    BRA Intr1


    RETFIE ; Return from interrupt

Intr1: ; take care of Interrupt 1
    ADDLW 0xFB ; W?(W-5). {note: SUBLW .5 will not work}
    BCF INTCON3, INT1IF ; Clear interrupt 1 flag
    BSF PORTB,4 ;Enable Right motor
    BSF PORTB,3 ;Enable Left Motor
    BCF PORTA,7 ;Backward Left
    BSF PORTA,6 ;Forward Right
    MOVLW .10
    CALL Delay
    BCF PORTB,4 ;Disable Right Motor
    BCF PORTB,3 ;Disable Left Motor
    RETFIE ; Return from interrupt

StartL: ; Initialization code to be executed during reset
    ; Initialize all I/O ports
    CLRF PORTA ; Initialize PORTA
    CLRF PORTB ; Initialize PORTB
    MOVLW 0x7F ; Set all A\D Converter Pins as
    MOVWF ADCON1 ; digital I/O pins
    MOVLW 0x0D ; Value used to initialize data direction
    MOVWF TRISA ; Set Port A direction
    MOVLW 0xC7 ; Value used to initialize data direction
    MOVWF TRISB ; Set Port B direction
    MOVLW 0x00 ; clear Wreg
    BSF INTCON, PEIE ; enable all peripheral interrupts
    BSF INTCON, INT0IE ; enable INT0
    BSF INTCON3, INT1IE ; enable INT1
    BCF INTCON3, INT1IP ; INT1 is set to low priority
    BSF RCON, IPEN ; enable priority levels on interrupts
    BCF INTCON, INT0IF ;flags must be cleared to allow an interrupt
    BCF INTCON3, INT1IF ;
    BSF INTCON, GIE ; enable interrupts globally
    MOVLW .10 ; Set starting delay to 0.5 seconds

MainL: ;Main loop
    BTG PORTB,5 ; LED Toggle
    CALL Delay
    BRA MainL
    ;Function to delay for Wreg x 0.1 seconds

Delay:
    MOVWF countOD

DelayOL: ; delay Outer loop
    CLRF countID

DelayIL: ; Delay Inner Loop
    INCF countID
    BNZ DelayIL
    DECF countOD
    BNZ DelayOL
    RETURN ; end delay function

    end ; Interrupt Example Program