;Program for 20 minute timer (FINAL) 
;				2009/7/18

;		Fuse and Lock bits are defaults.
;		[ != ] means 'not equal'.


.include "tn2313def.inc"

.def	W	=r16


.def	min_n	=r19
.def	led_n	=r20
.def	S_temp	=r21

.org	0x00
soft_r:	rjmp	reset
		rjmp	INTck
		nop
		nop
		nop
		rjmp	ovf1

.org	0x020
;Wake up from Sleep routine
INTck:		clr	W
		out	GIMSK,W		;Disable further INT0 interrupt
		reti 
;Main routine=======================================================
reset:		ldi	W,low(RAMEND)	;Set SPL
		out	SPL,W
		clr	min_n
		clr	led_n
	;Set MCUCR
		ldi	W,0b00110000	;bit7=0,Pull up enable
					;bit6/4=0/1,Power-down mode(Sleep)
					;bit5=1,Sleep Enable
					;bit3/2=0/0,INT1...no concern
					;bit1/0=0/0,INT0...interrupt at the low level
		out	MCUCR,W
	;Set IO Port
		ldi	W,0b00000000	;
		out	PORTB,W		;Clear Port B
		ldi	W,0b11111111
		out	DDRB,W		;Port B, all output
		ldi	W,0b00000100
		out	PORTD,W		;Clear Port D, Only PD2 is pull up INPUT.
		ldi	W,0b01111011	;
		out	DDRD,W

	;Set TMR1
		clr	W	
		out	TCCR1A,W	;bit7/4=0/0,OC1A/B port normal operation
					;bit3/2,reserved
					;bit1/0=0/0,CTC mode
		out	TCNT1H,W
		out	TCNT1L,W
		out	TIFR,W		;Clr interrupt flag
		out	EIFR,W		;Clr external interrupt flag
		ldi	W,3		;Set OCR1A 3*256+208=976,,,1.024msec*976=999.424msec
		out	OCR1AH,W
		ldi	W,208
		out	OCR1AL,W
		ldi	W,0b01000000
		out	GIMSK,W		;Enable INT0 interrupt

		sei			;Enable	Global interrupt
					
		sleep

;After wake up, TMR1 start
		sbi	PORTD,5		;Light on the 1st LED
		clr	W
		out	TIFR,W
		ldi	W,0b01000000
		out	TIMSK,W		;Enable OCF1A interrupt
		ldi	W,0b00001101	;TMR1 start
		out	TCCR1B,W	;bit7/6,no concern (input capture)
					;bit5,NIL
					;bit4/3=0/1,CTC on OCR1A
					;bit2/0=1,0,1, prescaler 1/1024, TMR1 Start
					;Wait for TMR1 interrupt
wait:		sei
		rjmp	wait
					

;================================================================================
;TMR1 overflow subroutine
ovf1:	
				


min_sq:		inc	min_n
		cpi	min_n,60
		brne	ovf_xt			;min != 60, exit from ovf1 routine

led_sq:		clr	min_n
		inc	led_n
led4:		cpi	led_n,4
		brne	led6
		sbi	PORTD,6
		rjmp	ovf_xt
led6:		cpi	led_n,6
		brne	led8
		sbi	PORTB,0
		rjmp	ovf_xt
led8:		cpi	led_n,8
		brne	led10
		sbi	PORTB,1
		rjmp	ovf_xt
led10:		cpi	led_n,10
		brne	led12
		sbi	PORTB,2
		rjmp	ovf_xt
led12:		cpi	led_n,12
		brne	led14
		sbi	PORTB,3
		rjmp	ovf_xt
led14:		cpi	led_n,14
		brne	led16
		sbi	PORTB,4
		rjmp	ovf_xt
led16:		cpi	led_n,16
		brne	led18
		sbi	PORTB,5
		rjmp	ovf_xt
led18:		cpi	led_n,18
		brne	led20
		sbi	PORTB,6
		rjmp	ovf_xt
led20:		cpi	led_n,20
		brne	ovf_xt
		sbi	PORTB,7
;		rjmp	ovf_xt



ovf_xt:		clr	W
		out	TIFR,W
		ldi	W,0b01000000
		out	TIMSK,W			;Enable ovf1 interrupt
		reti				;