164cx.asm

这是一个用单片机口模拟串口来驱动74LS164的汇编程序

	.device at90s1200
	.include "c:\avrtools\appnotes\1200def.inc" 
	.org 0000
	rjmp reset
	;.org 0001
	;rjmp adcb
	reti
	.org $02
	;rjmp t1zd
	reti
	reti
	reti
	
	;.org $06
	;rjmp tim0
	.org $07
reset:	;ldi r16,ramend		;初始化堆栈指针spl
	;out spl,r16
	ldi r16,0
	out ddrd,r16
	out portd,r16	
	ldi r16,255
	out ddrb,r16
	ldi r16,0
	out portb,r16
	;ldi r16,5
	;out tccr0,r16
	;ldi r16,0
	;out tcnt0,r16
	ldi r16,20
	
	sbi portb,1
	sbi ddrd,1
	sbi portd,1	
	;ldi r16,8		
	;out mcucr,r16		; 上升触发中断,int1
main:	;ldi r16,0
	;out timsk,r16
	;ldi r16,128
	;out gimsk,r16		
	;sei	
	cbi ddrd,2
	cbi portb,5
	sbi portd,2
	cbi portb,4
	cbi portb,3
	sbi ddrb,7
	sbi ddrb,6
	;sbi portd,6
	;cbi portd,1
	clr r20
	clr r2
	clr r0
	clr r21
	clr r14
	clr r15
	clr r13
	clr r12
	cbi portb,1
	;ldi r17,4
min1:	;ldi r24,0
	ldi r16,33
minn:	cbi portb,7
	sbi portb,6
	nop
	cbi portb,6
	;dec r16
	;brne min1
	ldi r22,255
pasef:	ldi r21,255
pasee:	dec r21
	brne pasee
	dec r22
	brne pasef
	dec r16
	brne minn
minm:	sbi portb,7
	sbi portb,6
	nop
	;sbi portb,7
	cbi portb,6
	cbi portb,7
	ldi r23,50
paseg:	ldi r21,255
paseb:	ldi r22,255
pasea:	dec r22
	brne pasea
	dec r21
	brne paseb
	dec r23
	brne paseg
	sbi portb,6
	nop
	cbi portb,6
	ldi r23,50
paseh:	ldi r21,255
pased:	ldi r22,255
pasec:	dec r22
	brne pasec
	dec r21
	brne pased
	dec r23
	brne paseh
	rjmp minm