ENGR2721 Practical 5

interrupts.inc

interrupt_init:
    movlw b'11100000' ; Enable global, enable periferal, enable t0
    movwf INTCON
    movlw b'00000000' ; Set INT1 to falling edge
    movwf INTCON2
    movlw b'00001000' ; Enable INT1
    movwf INTCON3
    movlw b'00000001' ; t1 overflow
    movwf PIR1
    ;; dont need to configure PIR2
    movlw b'00000001' ; Enable t1
    movwf PIE1
    ;; dont need to configure PIE2
    ;; dont need to configure PIR, PIR2 (priority is disabled)
    bcf RCON, IPEN ; disable interrupt priority
    return

INT_handler:
    btfsc INTCON3, INT1IF ; skip if INT1 flag bit clear
    call INT1_handler
    btfsc INTCON, TMR0IF ; skip if TMR0 flag bit clear
    call TMR0_handler
    btfsc PIR1, TMR1IF ; skip if TMR1 flag bit clear
    call TMR1_handler
    retfie FAST

pulse.asm

;;;---------------------------------------------
;;; ENGR2721 Microprocessors
;;; Prac 5, Pulse Generator
;;; Caitlyn Pascoe, 12/05/2023
;;;
;;; S3 = DAC, LCD
;;; S4 = AN0, AN1, PB0, PB1
;;;---------------------------------------------

#include <p18f452.inc>

  config OSC = HS
  config BOR = OFF, WDT = OFF, LVP = OFF

  org 0x0000
    goto start

  org 0x0008
    goto INT_handler

  org 0x0020

  constant delay =  d'125000'
  constant length = d'250000'

  cblock
    pulse_delay
    pulse_length
  endc

#include "../include/analog.inc"
#include "interrupts.inc"
#include "../include/LCD.inc"
#include "../include/ops.inc"
#include "../include/table.inc"
#include "timer.inc"

start:
    call analog_init
    call timer_init
    call interrupt_init
    call LCD_init
    bsf TRISB, 0 ; Set PB0 to input
    bsf TRISB, 1 ; Set PB1 to output

loop:
    call ADC_0
    movwf pulse_delay
    foreach TEXT_delay, LCD_ASCII
    call LCD_BCD
    call ADC_1
    movwf pulse_length
    foreach TEXT_length, LCD_ASCII
    call LCD_BCD
    goto loop

INT1_handler:
    bcf INTCON3, INT1IF ; clear INT flag bit
    call timer_reset
    movlw h'FF' ; 5V for DAC values
    call DAC_A ; set DAC_A high to begin trigger
    ; Set delay timer
    movf pulse_delay, w
    negf WREG
    movwf TMR0H
    clrf TMR0L
    bsf T0CON, TMR0ON ; start timer 0 to time delay
    return

TMR0_handler:
    movlw h'FF' ; 5V for DAC values
    call DAC_B ; set DAC_B high to begin pulse
    ; Set length timer
    movf pulse_length, w
    negf WREG
    movwf TMR1H
    clrf TMR1L
    bsf T1CON, TMR1ON ; start timer 1 to time length
    return

TMR1_handler:
    clrf WREG
    call DAC_A
    call DAC_B ; set DAC_A and DAC_B low to end cycle

TEXT_delay:
  dw 'Delay: '

TEXT_length:
  dw 'Length: '

  end

timer.inc

;;;=============================================
;;; PIC Trainer timer support
;;;=============================================

timer_init:
    movlw b'00000010' ; 16-bit, internal clock, prescaler, 1:8
    movwf T0CON
    movlw b'10110000' ; 16-bit, 1:8, internal clock
    movwf T1CON
    return

timer_reset:
    bcf T0CON, TMR0ON ; Stop timer0
    clrf TMR0L ; Clear timer0 value
    clrf TMR0H
    bcf T1CON, TMR1ON ; Stop timer1
    clrf TMR1L ; Clear timer1 value
    clrf TMR1H
    return

timer0_load macro value
    movlw high(-value)
    movwf TMR0H
    movlw low(-value)
    movwf TMR0L
  endm

timer1_load macro value
    movlw high(-value)
    movwf TMR1H
    movlw low(-value)
    movwf TMR1L
  endm