sg9.asm

the practice of proteus and avr

.device AT90S8535
.equ    sph    	=$3E
.equ    spl    	=$3D
.equ	PORTC	=$15
.equ	DDRC	=$14 		
.equ    PINC    =$13
.equ    TIMSK   =$39
.equ    OCR1AH  =$2B
.equ    OCR1AL  =$2A
.equ    TCCR1B  =$2E
.equ    SREG	=$3F
.equ    TCNT1H	=$2D
.equ    TCNT1L	=$2C

	.org	$0000
	rjmp	main
	.org	$006
	rjmp	t1_cp

main:	ldi	r16,$02			;栈指针置初值
	out	sph,r16
	ldi	r16,$5f
	out	spl,r16
	ldi	r16,$01			;PC0口定义为输出口
	out	DDRC,r16
	ldi	r16,$10			;允许T1比较匹配A中断
	out	TIMSK,r16
	clr	r16			;置TCNT1初值为0
	out	TCNT1L,r16
	out	TCNT1H,r16
	ldi	r16,$7a			;OCRLA置$7A12，即1s中断1次
	out	OCR1AH,r16
	ldi	r16,$12
	out	OCR1AL,r16
	ldi	r16,$0c			;T/C1对主频256分频定时
	out	TCCR1B,r16
	sei
	
here:	rjmp	here

t1_cp:	in	r1,sreg			;保护标志
	in	r2,PORTC		;PC口取反
	com	r2
	out	PORTC,r2
	out	sreg,r1			;标志恢复
	reti