I2C Problem LPC1768

#include "i2c.h"

#include "type.h"

//////////////////////////////////////////////////////////////////////////

void init_i2c (void)

{

    // I2C Disable

    LPC_I2C2->I2CONCLR |= (1<<6);

    // CPU Taktteiler fuer I2C1

    //PCLKSEL1_bit.PCLK_I2C1 = 0;   // CCLK/4

    LPC_SC->PCLKSEL1 |= (1<<20);   // CCLK/1

    //PCLKSEL1_bit.PCLK_I2C1 = 2;   // CCLK/2

    //PCLKSEL1_bit.PCLK_I2C1 = 3;   // CCLK/8

    LPC_SC->PCONP |= (1 << 26);

    LPC_PINCON->PINSEL0 |= (1 << 21) | (1 << 23);   //Select SDA2 and SCL2 on PIN P0.10 and P0.11

    LPC_PINCON->PINMODE0 |= (1 << 21) | (1 << 23);

    LPC_PINCON->PINMODE_OD0 |= (1 << 10);

    LPC_PINCON->PINMODE_OD0 |= (1 << 11);  

    // I2C Takt

    // I2C Frequenz = PCLK_I2C / (I2C_I2SCLH + I2C_I2SCLL)

    // Register Wert ist Anzahl von Taktzyklen fuer high- oder low-Time

    LPC_I2C2->I2SCLH = 255/2;  // High-Time

    LPC_I2C2->I2SCLL = 255/2;  // Low-Time

    // I2C Configuration Register

    LPC_I2C2->I2CONCLR |= (1<<2);   // ACK Flag Clear           AAC

    LPC_I2C2->I2CONCLR |= (1<<3);   // Interrupt Flag Clear     SIC

    LPC_I2C2->I2CONCLR |= (1<<5);  // Start Flag Clear         STAC

    LPC_I2C2->I2CONSET |= (1<<6);  // I2C Enable               I2EN

}

///////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////

unsigned char write_i2c (unsigned char addr, unsigned char *data, unsigned char data_cnt)

{

    unsigned char i;

    // Start ausgeben

    LPC_I2C2->I2CONSET |= (1<<5);         //STA = 1

    // Auf Interrupt warten (Start fertig)

    while (!((LPC_I2C2->I2CONSET >> 3) & 0x01));

    if (LPC_I2C2->I2STAT != 0x08) return 11;//FALSE;

    // Adresse ausgeben

    LPC_I2C2->I2DAT = addr<<1;        // Write = 8. Bit low

    // Start ruecksetzen

    LPC_I2C2->I2CONCLR |= (1 << 5);   //Start zurücksetzen

    LPC_I2C2->I2CONCLR |= (1 << 3);   //Interrupt zurücksetzen

    // Auf Interrupt warten (ACK Adresse + Write)

    // Hier bleibt der Controller hängen!!!

    while (!((LPC_I2C2->I2CONSET >> 3) & 0x01));

    if (LPC_I2C2->I2STAT != 0x18) return 22;//FALSE;

    for (i = 0; i < data_cnt; i++)

    {

        // Daten ausgeben

        LPC_I2C2->I2DAT = data[i];

        // Interrupt ruecksetzen

        LPC_I2C2->I2CONCLR |= (1 << 3);

        // Auf Interrupt warten (TX fertig + ACK)

        while (!((LPC_I2C2->I2CONSET >> 3) & 0x01));

        if (((LPC_I2C2->I2STAT >> 2) & 0x1F) != 0x28) return 33;//FALSE;

    }

    //I2C1CONCLR_bit.SIC = 1; // Interrupt ruecksetzen

    LPC_I2C2->I2CONCLR |= (1 << 3);

    // Stop ausgeben

    LPC_I2C2->I2CONSET |= (1 << 4);

    return TRUE;

}

///////////////////////////////////////////////////////////////////////////

    char retVal = 0;

    int i = 0;

    unsigned char cmd[4];

    for(i = 0; i < 4;i++){

        cmd[i] = 0;

    }

    init_i2c ();

    int addr = 0x90;

    cmd[0] = 0xAC;

    cmd[1] = 0x02;

    retVal = write_i2c (addr, cmd, 2);