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i2c.c
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i2c.c
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/* I2C (TwoWire) AVR library
*
* Copyright (C) 2015-2017 Sergey Denisov.
* Rewritten by Sergey Denisov aka LittleBuster (DenisovS21@gmail.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public Licence
* as published by the Free Software Foundation; either version 3
* of the Licence, or (at your option) any later version.
*/
#include "i2c.h"
void i2c_init(void)
{
TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
//defaults: TWBR = 0, TWPS1 = TWPS0 = 0 -> TWI clock = FCPU / 16
// CPU @ 2MHz, twi clock 125kHz
}
bool i2c_start_condition(void)
{
TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN);
while (i2c_busy());
return TW_START == i2c_status() || TW_REP_START == i2c_status();
}
void i2c_stop_condition(void)
{
TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN);
}
void i2c_send_byte(unsigned char byte)
{
TWDR = byte;
TWCR = _BV(TWINT) | _BV(TWEN);
while (i2c_busy());
}
void i2c_send_packet(unsigned char value, unsigned char address)
{
i2c_start_condition();
i2c_send_byte(address);
i2c_send_byte(value);
i2c_stop_condition();
}
uint8_t i2c_recv_byte(void)
{
TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWEA);
while (i2c_busy());
return TWDR;
}
uint8_t i2c_recv_last_byte(void)
{
TWCR = _BV(TWINT) | _BV(TWEN);
while (i2c_busy());
return TWDR;
}