#include "i2c.h"
#include <util/delay.h>

void i2c_init(void)
{
	i2c_sda_hi();
	i2c_scl_hi();
	_delay_us(i2cbitdelay);
}

void i2c_writebit( uint8_t c )
{
    if ( c > 0 ) {
        i2c_sda_hi();
    } else {
        i2c_sda_lo();
    }

    i2c_scl_hi();
    _delay_us(i2cbitdelay);

    i2c_scl_lo();
    _delay_us(i2cbitdelay);

    if ( c > 0 ) {
        i2c_sda_lo();
    }
    _delay_us(i2cbitdelay);
}

uint8_t i2c_readbit(void)
{
    i2c_sda_hi();
    i2c_scl_hi();
    _delay_us(i2cbitdelay);

    uint8_t c = bitRead( SDAPORT,SDAPIN);

    i2c_scl_lo();
    _delay_us(i2cbitdelay);

    return c ? 1 : 0;
}

void i2c_start(void)
{
    i2c_sda_hi();
    i2c_scl_hi();

    _delay_us(i2cbitdelay);
   
    i2c_sda_lo();
    _delay_us(i2cbitdelay);

    i2c_scl_lo();
    _delay_us(i2cbitdelay);
}

void i2c_repstart(void)
{
    i2c_sda_hi();
    i2c_scl_hi();

    i2c_scl_lo();                           // force SCL low
    _delay_us(i2cbitdelay);

    i2c_sda_release();                      // release SDA
    _delay_us(i2cbitdelay);

    i2c_scl_release();                      // release SCL
    _delay_us(i2cbitdelay);

    i2c_sda_lo();                           // force SDA low
    _delay_us(i2cbitdelay);
}

void i2c_stop(void)
{
    i2c_scl_hi();
    _delay_us(i2cbitdelay);

    i2c_sda_hi();
    _delay_us(i2cbitdelay);
}

uint8_t i2c_write( uint8_t c )
{
    for ( uint8_t i=0;i<8;i++) {
        i2c_writebit( c & 128 );
        c<<=1;
    }

    return i2c_readbit();
}

uint8_t i2c_read( uint8_t ack )
{
    uint8_t res = 0;

    for ( uint8_t i=0;i<8;i++) {
        res <<= 1;
        res |= i2c_readbit();  
    }

    if ( ack )
        i2c_writebit( 0 );
    else
        i2c_writebit( 1 );

    _delay_us(i2cbitdelay);

    return res;
}