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

;I2C bus 1 support:

;Start I2C-1 communications:
;Input:	temp - device address

I2C1_Start:
	Port_SDA1_0			;force SDA low
	rcall	I2C_qp_delay		;quarter period delay

;Write data byte via I2C-1:
;Input:	temp - data byte
;Out:	C = ASK

I2C1_Wr:
	sec				;set carry flag
	rol	temp			;shift in carry and out bit one
	rjmp	i2c1_wr_first
i2c1_wr_bit:
	lsl	temp			;if transmit register empty
i2c1_wr_first:
	breq	i2c1_get_ack		; goto get acknowledge
	Port_SCL1_0			;force SCL low
	brcc	i2c1_wr_low		;if bit high
	nop				; (equalize number of cycles)
	Port_SDA1_Z			; release SDA
	rjmp	i2c1_wr_high
i2c1_wr_low:				; else
	Port_SDA1_0			;  force SDA low
	rjmp	i2c1_wr_high		;  (equalize number of cycles)
i2c1_wr_high:
	rcall	I2C_hp_delay		;half period delay
	Port_SCL1_Z			;release SCL
	rcall	I2C_hp_delay		;half period delay
	rjmp	i2c1_wr_bit
i2c1_get_ack:
	Port_SCL1_0			;force SCL low
	nop
	nop
	Port_SDA1_Z			;release SDA
	rcall	I2C_hp_delay		;half period delay
	Port_SCL1_Z			;release SCL
	rcall	I2C_hp_delay		;half period delay
	clc				;clear carry flag
	Skip_if_Port_SDA1_0		;if SDA is high
	sec				; set carry flag
	rcall	I2C_hp_delay		;half period delay
	ret

;Read data byte via I2C-1:
;Out:	temp - data byte

I2C1_Rd:
	ldi	temp,0x01		;data = 0x01
i2c1_rd_bit:				;do
	Port_SCL1_0			; force SCL low
	rcall	I2C_hp_delay		; half period delay
	Port_SCL1_Z			; release SCL
	rcall	I2C_hp_delay		; half period delay
	clc				; clear carry flag
	Skip_if_Port_SDA1_0		; if SDA is high
	sec				;  set carry flag
	rol	temp			; store data bit
	brcc	i2c1_rd_bit		;while receive register not full
	Port_SCL1_0			;force SCL low
	nop
	nop
	Port_SDA1_0			;force SDA low (ASK=0)
	rcall	I2C_qp_delay		;quarter period delay
	Port_SCL1_Z			;release SCL
	rcall	I2C_hp_delay		;half period delay
	ret

;Stop I2C-1 communications:

I2C1_Stop:
	Port_SCL1_0			;force SCL low
	nop
	nop
	Port_SDA1_0			;force SDA low
	rcall	I2C_hp_delay		;half period delay
	Port_SCL1_Z			;release SCL
	rcall	I2C_qp_delay		;quarter period delay
	Port_SDA1_Z			;release SDA
	rcall	I2C_hp_delay		;half period delay
	ret

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

;I2C half clock period delay:
;(normal: 5.0us / fast: 1.3us)

I2C_hp_delay:
	ldi	Cnt,I2CDelHp
i2c_hp_delay_loop:
	dec	Cnt
	brne	i2c_hp_delay_loop
	ret

;I2C quarter clock period delay:
;(normal: 2.5us / fast: 0.6us)

I2C_qp_delay:
	ldi	Cnt,I2CDelQp	
i2c_qp_delay_loop:
	dec	Cnt
	brne	i2c_qp_delay_loop
	ret