notes.txt

as3050 interfacing with atmega8

/*
  in	r0,SREG		; store SREG
	ldi	temp1,(256-N+8)
	out	TCNT0,temp1	; reset T/C0 to one bit length
	inc	bit_cnt		; increment bit counter
	sbrs	u_stat,TXC	; if (transmit complete flag clear)
	rjmp	transmit	;    goto transmit

to_0:	
	sec			; set carry
	sbis	PIND,RXPIN	; if (RxD == LOW)
	clc			;	clear carry
	ror	u_data		; shift carry into u_data

	cpi	bit_cnt,8	; if (bit_cnt == 8)
	brne	to_1		; {
	clr	temp1		;    disable T/C0 Overflow Interrupt
	out	TIMSK,temp1
	sbr	u_stat,1<<RXC	;    set receive complete
to_1:				; }
	out	SREG,r0	        ; restore SREG
	reti			; exit

transmit:
	cpi	bit_cnt,1	; if (bit_cnt == 1)	\\ start bit
	brne	to_2		; {
	cbi	PORTD,TXPIN	;	generate start bit
	rjmp	to_1		;	exit
to_2:				; }
	cpi	bit_cnt,10	; if (bit_cnt == 10)	\\ stop bit
	brne	to_3		; {
	sbi	PORTD,TXPIN	;	generate stop bit
	clr	temp1		;	disable TC0 overflow interrupt
	out	TIMSK,temp1
	sbr	u_stat,1<<TXC	;	set transmit complete bit
	rjmp	to_1		;	exit
to_3:				; }
	sbrc	u_data,0	; if (LSB set)
	sbi	PORTD,TXPIN	;	PD3 = HIGH
	sbrs	u_data,0	; if (LSB clear)
	cbi	PORTD,TXPIN	;	PD3 = LOW
	lsr	u_data		; shift left u_data
	rjmp	to_1	


*/