#include "i2c.h"

void initI2C(void) {
  TWBR = 32;                               /* set bit rate, see p. 242 */
                                     /* 8MHz / (16+2*TWBR*1) ~= 100kHz */
  TWCR |= (1 << TWEN);                                       /* enable */
}

void i2cWaitForComplete(void) {
  loop_until_bit_is_set(TWCR, TWINT);
}

void i2cStart(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWSTA));
  i2cWaitForComplete();
}

void i2cStop(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWSTO));
}

uint8_t i2cReadAck(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWEA));
  i2cWaitForComplete();
  return (TWDR);
}

uint8_t i2cReadNoAck(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN));
  i2cWaitForComplete();
  return (TWDR);
}

void i2cSend(uint8_t data) {
  TWDR = data;
  TWCR = (_BV(TWINT) | _BV(TWEN));                  /* init and enable */
  i2cWaitForComplete();
}