; Prac 4 - Using the AVR PWM

;******************************************************
.include "8515def.inc"
        rjmp RESET 		;Reset Handle
        reti			; We don't use INT0
        ;<INSERT CODE HERE >	; Jump to INT1 ISR
;******************************************************

RESET:
.def temp =r16
.def temp2 = r17

        ldi temp,low(RAMEND)
        out SPL,temp
        ldi temp,high(RAMEND)
        out SPH,temp        ;init Stack Pointer

		; Initialise PORTB for input
		;<INSERT CODE HERE >

        ; Initialise PORTD - INT1 must be set as input, OC1A to output
		;<INSERT CODE HERE >
        
        ; Set the initial value for the timer to count to
		;<INSERT CODE HERE >
        
        ; Select as 8-bit PWM
		;<INSERT CODE HERE >

		; Select timer to run at full clock speed
		;<INSERT CODE HERE >

        ; Enable the INT1 interrupt
		;<INSERT CODE HERE >
		
        ; Enable interrupt on falling edge of INT1 (the pushbuttons are active-low)
		;<INSERT CODE HERE >
		
        ; Enable interrupts
        ;<INSERT CODE HERE >

        ; Sit back and wait for interrupts to happen
mainloop: 
        rjmp mainloop


        ; INT1 Service routine
        ; We don't use any other registers in the program, so don't have to save them
INT1_ISR:
		; Read in data from PORTB
        ;<INSERT CODE HERE >
        
        ; Output it to the PWM register
        ;<INSERT CODE HERE >
        
        ; Return from the interrupt
        ;<INSERT CODE HERE >