;1-Wire port support:

;Send reset pulse and receive presence pulse:

TRes1:	Port_OWP1_0		;OWP1 <- 0
	ldi	Cnt,250
	rcall	Delay		;delay 250 uS
	ldi	Cnt,250
	rcall	Delay		;delay 250 uS
	cli			;interrupts disable
	Port_OWP1_Z		;OWP1 <- 1
	ldi	Cnt,14
	rcall	Delay		;delay 14 uS
	Skip_if_Port_OWP1_1
	rjmp	RFail1
	ldi	Cnt,52
	rcall	Delay		;delay 52 uS
	Skip_if_Port_OWP1_0
	rjmp	RFail1
	sei			;interrupts enable
	ldi	Cnt,250
	rcall	Delay		;delay 250 uS
	Skip_if_Port_OWP1_1
	rjmp	RFail1
	rcall	SetPr1		;set present
	rjmp	Rret1
RFail1:	sei			;interrupts enable
	rcall	ClrPr1		;present flag clear
	rcall	ClrTv1		;clear T valid flag	
Rret1:	ret

;R/W byte via 1-wire port:
;temp - data byte

TByte1:	push	Cnt
	ldi	Cnt,8		;bit counter
tb1:	ror	temp		;shift data byte
	rcall	TBit1		;send bit
	dec	Cnt
	brne	tb1
	ror	temp		;shift last bit
	pop	Cnt
	ret

;R/W one bit via 1-wire port:

TBit1:	push	Cnt
	push	temp
	cli			;interrupts disable
	Port_OWP1_0		;OWP1 <- 0
	ldi	Cnt,2
	rcall	Delay		;delay 2 uS
	brcc	bit01
	Port_OWP1_Z		;OWP1 <- 1 if C == 1
bit01:	ldi	Cnt,13
	rcall	Delay		;delay 13 uS
	clc
	Skip_if_Port_OWP1_0
	sec
	ldi	Cnt,45
	rcall	Delay		;delay 45 uS
	Port_OWP1_Z		;OWP1 <- 1
	sei			;interrupts enable
	ldi	Cnt,2
	rcall	Delay		;delay 2 uS
	rcall	Do_CRC		;update CRC
	pop	temp
	pop	Cnt
	ret

;----------------------------------------------------------------------------

;Update CRC:
;In: CRC, C - data bit
;Out: new CRC

Do_CRC:	in	temp,SREG	;save C
	push	temp
	rol	temp		;temp.0 <- C	
	eor	temp,CRC    	;temp.0 eor CRC.0
	ror	temp          	;temp.0 -> C
	brcc	ZERO1
	ldi	temp,0x18
	eor	CRC,temp    	;update the CRC value
ZERO1:	ror	CRC          	;position the new CRC
	pop	temp
	out	SREG,temp	;restore C
	ret

;----------------------------------------------------------------------------

;Delay:
;Cnt - delay value, uS (2uS min)
;CAUTION! Code is timed for 11.059 MHz 

Delay:	dec	Cnt
	nop
	nop
	nop
	nop
De:	dec	Cnt
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	brne	De
	ret