#include "project.h"


#define SCL ((u8) 1 <<4)
#define SDA ((u8) 1 <<5)
#define BANK GPIOB


static u8
set (u8 sda, u8 scl)
{
  u8 ret;

  if (sda)
    GPIO_WriteHigh (BANK, SDA);
  else
    GPIO_WriteLow (BANK, SDA);

  if (scl)
    GPIO_WriteHigh (BANK, SCL);
  else
    GPIO_WriteLow (BANK, SCL);

  delay (4);
  //delay_us (10);
  ret = (GPIO_ReadInputData (BANK) & SDA) ? 1 : 0;

  return ret;
}




u8
i2cb_send (u8 wot)
{
  u8 i;

  for (i = 0; i < 8; ++i) {
    set (wot & 0x80, 0);
    set (wot & 0x80, 1);
    set (wot & 0x80, 0);
    wot <<= 1;
  }

  set (1, 0);
  i = set (1, 1);
  set (1, 0);

  return i;
}

u8
i2cb_send_addr (u8 addr, u8 rnw)
{
  return i2cb_send (addr << 1 | rnw);
}

int
i2cb_send_data (u8 d)
{
  return i2cb_send (d);
}

u8
i2cb_read (u8 ack)
{
  u8 i, wot = 0;

  for (i = 0; i < 8; ++i) {
    wot <<= 1;
    set (1, 0);
    wot |= set (1, 1);
    set (1, 0);
  }

  set (ack, 0);
  set (ack, 1);
  set (ack, 0);
  return wot;
}


void
i2cb_start (void)
{
  set (1, 1);
  set (0, 1);
  set (0, 0);
}

void
i2cb_stop (void)
{
  set (0, 0);
  set (0, 1);
  set (1, 1);
}


int
i2cb_start_transaction (u8 a, u8 rnw)
{
  i2cb_start();
  return i2cb_send_addr (a, rnw);

}


void
i2cb_reset (void)
{
  i2cb_start();
  i2cb_stop();
  i2cb_start();
  i2cb_stop();
}



#if 0
void
i2cb_scan (void)
{
  u8 r;
  u16 i;

  i2cb_reset();

  for (i = 0; i < 128; ++i) {
    i2cb_start();
    i2cb_stop();
    i2cb_start();
    r = i2cb_send ((i << 1) | I2C_WRITE);
    i2cb_stop();

    if (!r)
      printf ("target found at %02x\n", i);

  }

  i2cb_reset();

}
#endif

void
i2cb_init (void)
{
  GPIO_Init (BANK, SDA, GPIO_MODE_OUT_OD_HIZ_SLOW);
  GPIO_Init (BANK, SCL, GPIO_MODE_OUT_OD_HIZ_SLOW);

  set (1, 1);
  set (0, 1);
  set (1, 0);
  set (1, 1);
}