//******************************************************************************

__inline void i2c_force_scl(void)
{
PGDR &= ~SCL;
}

__inline void i2c_release_scl(void)
{
PGDR |= SCL;
}

__inline void i2c_force_sda(void)
{
PGDR &= ~SDA;
PGDDR |= SDA;
}

__inline void i2c_release_sda(void)
{
PGDDR &= ~SDA;
}

__inline u_int i2c_read_sda(void)
{
return (PGDR & SDA);
}

//******************************************************************************

int i2c_ini(void)
{
// HW
EEDrive = 0x00;
PGDR &= ~SDA;
PGDR |= SCL;
PGDDR &= ~SDA;
PGDDR |= SCL;

return 0;
}

u_int i2c_write_byte(u_int data)
{
u_int a;

for(a = 0; a < 8; a++)
{
i2c_force_scl();
i2c_qp_dly();
data <<= 1;
if(data & (1 << 8)) i2c_release_sda();
else i2c_force_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_hp_dly();
}

i2c_force_scl();
i2c_qp_dly();
i2c_release_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_hp_dly();
if(i2c_read_sda()) return 1;
else return 0;
}

u_int i2c_read_byte(u_int ack)
{
u_int a, data;

data = 0;
for(a = 0; a < 8; a++)
{
i2c_force_scl();
i2c_qp_dly();
i2c_release_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_hp_dly();

data <<= 1;
if(i2c_read_sda()) data |= 1;
}
i2c_force_scl();
i2c_qp_dly();
if(!ack) i2c_force_sda();
else i2c_release_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_hp_dly();

return data;
}

void i2c_start(void)
{
i2c_force_scl();
i2c_qp_dly();
i2c_release_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_qp_dly();

i2c_force_sda();
i2c_hp_dly();
}

void i2c_stop(void)
{
i2c_force_scl();
i2c_qp_dly();
i2c_force_sda();
i2c_qp_dly();
i2c_release_scl();
i2c_qp_dly();
i2c_release_sda();
i2c_qp_dly();
}

void i2c_qp_dly(void)
{
u_int a = 0x80;
while(--a) __asm{nop};
}

void i2c_hp_dly(void)
{
u_int a = 0x100;
while(--a) __asm{nop};
}

//******************************************************************************