C7-Serial-Communication/i2c.c at main · Ver12/C7-Serial-Communication · GitHub

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/*  Author: Steve Gunn
 * Licence: This work is licensed under the Creative Commons Attribution License.
 *          View this license at http://creativecommons.org/about/licenses/
 */

#include "i2c.h"

void init_i2c_master(void)
{
	/* F_SCL = F_CPU/120 = 100kHz */
	TWBR = 0x34;
	TWSR = 0x00;
}

void i2c_start(void)
{
	TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN);
	while(!(TWCR & _BV(TWINT)));
}

void i2c_stop(void)
{
	TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN);
}

void i2c_tx(uint8_t b)
{
	TWDR = b;
	TWCR = _BV(TWINT) | _BV(TWEN);
	while(!(TWCR & _BV(TWINT)));
}

uint8_t i2c_rx_ack(void)
{
	TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWEA);
	while(!(TWCR & _BV(TWINT)));
	return TWDR;
}

uint8_t i2c_rx_nack(void)
{
	TWCR = _BV(TWINT) | _BV(TWEN);
	while(!(TWCR & _BV(TWINT)));
	return TWDR;
}