#define WSH() PORTB |= (1 << PB2)
#define WSL() PORTB &= ~(1 << PB2)
#define BCKH() PORTB |= (1 << PB1)
#define BCKL() PORTB &= ~(1 << PB1)
#define DATH() PORTB |= (1 << PB0)
#define DATL() PORTB &= ~(1 << PB0)

inline void i2s_send_bit(uint16_t n, uint8_t pos)
{
  if ( n & (1 << pos) ) DATH(); else DATL();
  NOP(); NOP();
  BCKH();
  NOP(); NOP();
  BCKL();
}

void i2s_send(const uint16_t data) {
  WSL();
  _delay_us(2);

  uint8_t i = 15;
  for(; i; i--) {
    i2s_send_bit(data, i);
  }
  WSH();
  i2s_send_bit (data, 0);

  for(i = 15; i; i--) {
    i2s_send_bit(data, i);
  }
  WSL();
  i2s_send_bit (data, 0);
}