MSP430g2 i2c - SDA held low

* I2C LIBRARY FOR MSP430F2132 WITHOUT INTERRUPT
* created by Petus (c) 2013
*
* please, visit the website http://petus.cz
*
*/

#include "msp430g2553.h";

//---------I2C INICIALIZATION----------------------
void i2c_init(unsigned int slave_address)
{
	P1SEL |= BIT6 + BIT7;                     // set of pins
	P1SEL2 |= BIT6 + BIT7;                     // set of pins
	UCB0CTL1 |= UCSWRST;                      // enable SW reset
	UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master
	UCB0CTL1 = UCSSEL_2 + UCSWRST;            // SMCLK, keep SW reset
	UCB0BR0 = 12;                             // fSCL = SMCLK/12 = ~100kHz
	UCB0BR1 = 0;
	UCB0I2CSA = slave_address;                // Set slave address
	UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation

}
//----------CHANGE OF ADDRESS--------------
void i2c_adr(unsigned int adr)
{
	UCB0I2CSA = adr;
}

//----------SEND DATA WITH A START BIT------
void i2c_tx(unsigned char data)
{
	while((UCB0STAT & BUSY)!= 0);			         // free bus
	while (UCB0CTL1 & UCTXSTP);			           // stop
	UCB0CTL1 |= UCTR;                          // UCTR=1 => Transmit Mode (R/W bit = 0)
	UCB0CTL1 |= UCTXSTT;                       // start condition generation
	while((IFG2  & UCB0TXIFG ) ==0);
	UCB0TXBUF = data;
	__delay_cycles(200);
}

//----------SEND DATA WITHOUT START BIT--------
void i2c_txx(unsigned char data1)
{
	while((IFG2  & UCB0TXIFG ) ==0);		       // buffer is filled
	UCB0TXBUF = data1;
	__delay_cycles(200);
}

//----------SEND STRING WITHOUT START BIT----------
void i2c_retez(const char *s)
{
	while((UCB0STAT & BUSY)!= 0);			         // free bus
	while(*s)
		i2c_txx(*s++);

}


//-----------READ WITH START BIT-------------
unsigned char i2c_rx(void)
{

	while((UCB0STAT & BUSY)!= 0);			         // free bus
	UCB0CTL1 &= ~UCTR;                         // recive
	UCB0CTL1 |= UCTXSTT;
	while(UCB0CTL1 & UCTXSTT);				         // start
	while((IFG2  & UCB0RXIFG ) ==0);		       // char is complete
	return UCB0RXBUF;
}

//-----------READ WITHOUT START BIT------------
unsigned char i2c_rxx(void)
{

	while((UCB0STAT & BUSY)!= 0);			         // free bus

	while((IFG2  & UCB0RXIFG ) ==0);		       // char is complete
	return UCB0RXBUF;
}

//---------------STOP-------------------------
void i2c_stop(void)
{
	while((UCB0STAT & BUSY)!= 0);
	UCB0CTL1 |= UCTXSTP;
	while(UCB0CTL1 & UCTXSTP);
}

//---------STOP WITH NACK-------------
void i2c_stopNACK(void)
{
	while((UCB0STAT & BUSY)!= 0);
	UCB0CTL1 |= UCTXNACK;
}


int main()
{
	_delay_cycles(1000);

while(1){
	i2c_init(0x40);
	i2c_tx(0xfa);
	i2c_rx();
	
	_delay_cycles(400);
}
}