/*  I2C Programm mit kleinen Fehler x/y/z Werte werden nicht ab i=0 bis 5 sondern ab i=1-5 und dann 0 abgespeichert!!! 
    1.byte lower byte(x0) 2.byte higher(x1) */


#include <msp430.h>
#include <stdint.h>
uint8_t address = 0x53;
void i2c_write(uint8_t address, uint8_t* data, uint8_t len);
unsigned char I2C_ReadByte(uint8_t address, unsigned char registerAddr, uint8_t* data,int index);
void i2c_init();
void uart_init();
 

int main(void) 
{
    WDTCTL = WDTPW | WDTHOLD;    // stop watchdog timer

    BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;
        
    uint8_t start0[] = {}; 
    uint8_t data_format[] = {0x31,0x08};//reg0x31, 0x08 = full resolution +-2g  
    uint8_t bw_rate[] = {0x2C,0x0A};	//reg0x2C,0x0A = 100Hz
    uint8_t power_ctl[] = {0x2D,0x08};  //reg0x2D,0x08 = measure
    uint8_t offset_x[] = {0x1E,0xFD};   //reg0x1E,x-Axis calibration
    uint8_t offset_y[] = {0x1F,0xFD};
    uint8_t offset_z[] = {0x20,0x02};
    //uint8_t system =0;
    uint8_t axis[26] ;
    int maxindex = 5;			//maxindex = (maximum of read bytes)-1
    
    uart_init();
    i2c_init();   
    i2c_write(address,start0,0); 
    __delay_cycles(5000);
    i2c_write(address,data_format,2);
    __delay_cycles(5000); 
    i2c_write(address,bw_rate,2);
    __delay_cycles(5000);
    i2c_write(address,power_ctl,2);
    __delay_cycles(5000);
    i2c_write(address,offset_x,2);
    __delay_cycles(5000);
    i2c_write(address,offset_y,2);
    __delay_cycles(5000);
    i2c_write(address,offset_z,2);
    __delay_cycles(5000);
    
    while(1)
    {
      I2C_ReadByte(address,0x32,axis,maxindex); //read 6 bytes from address 0x32-0x37
      
      /*   die for schleife sollte eigentlich von 0 an laufen, 
           aber bei axis(0) zeigt er Inhalt von Register 0x37=axis(5) an ??? 
           die Speicherinhalte werden genau um 1 verschoben abgespeichert*/
    
      for(int i = 1;i <= maxindex; i++)		
      { 
      UCA0TXBUF = axis[i];
      __delay_cycles(5000);
      }
      UCA0TXBUF = axis[0];
      __delay_cycles(5000);
      UCA0TXBUF = 0x0D;
      __delay_cycles(500000);  //wait busy
    }
}


void i2c_init()
{
    P1SEL |= BIT6 + BIT7;
    P1SEL2 |= BIT6 + BIT7;

    UCB0CTL1 |= UCSWRST;
    UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;
    UCB0BR0 = 10;
    UCB0BR1 = 0;
    UCB0CTL1 = UCSSEL_2;
    UCA0CTL1 &= ~UCSWRST; //Take UCA0 out of reset

}

void uart_init()
{
   
    P1SEL |= BIT1 + BIT2 ;
    P1SEL2 |= BIT1 + BIT2;

    UCA0CTL1 = UCSWRST; //UCA0 in Reset   
    UCA0CTL1 |= UCSSEL_2; // SMCLK
    UCA0BR0 = 104; // 1MHz 9600
    UCA0BR1 = 0; // 1MHz 9600
    UCA0MCTL = UCBRS0; // Modulation UCBRSx = 1
    
}

void i2c_write(uint8_t address, uint8_t* data, uint8_t len) 
{
    // Warten, bis Bus frei
    while (UCB0CTL1 & UCTXSTP) {
    }

    UCB0I2CSA = address; // Slave Adresse setzen
    UCB0CTL1 |= UCTR + UCTXSTT;      // W-Mode, Start der Übertragung

    // Senden der Datenbytes
    for (uint8_t i = 0; i < len; i++) 
    {
        while (!(IFG2 & UCB0TXIFG)) 
        {
        }
        UCB0TXBUF = data[i];
        //UCA0TXBUF = data[i];
    }
    
    // Senden der Stoppsequenz
    while (!(IFG2 & UCB0TXIFG)) {
    }
    UCB0CTL1 |= UCTXSTP;
}

unsigned char I2C_ReadByte(uint8_t address, unsigned char registerAddr, uint8_t* data,int index) 
{

    UCB0I2CSA = address;      // Set slave address
    UCB0CTL1 |= UCTR + UCTXSTT;    // I2C TX, start condition

    // Wait for transmit buffer to be ready
    while (!(IFG2 & UCB0TXIFG));
    UCB0TXBUF = registerAddr;      // Send register address

    // Wait for transmit to finish
    while (!(IFG2 & UCB0TXIFG));
    UCB0CTL1 &= ~UCTR;             // I2C RX
    UCB0CTL1 |= UCTXSTT;           // I2C start (repeated)
    while (!(IFG2 & UCB0RXIFG)) // Wait for receive buffer to be ready
    
    //while (UCB0CTL1 & UCTXSTT)  // Wait for start to finish
    {}
   
    //if(index != 0)
   // {
      for(int i=0;i < index; i++)
      {
      data[i] = UCB0RXBUF;         // Read data    
      while (!(IFG2 & UCB0RXIFG)); // Wait for receive buffer to be ready
      }
    //} 
    UCB0CTL1 |= UCTXSTP;           // I2C stop            
    data[index] = UCB0RXBUF;       // Read data
    while ((UCB0CTL1 & UCTXSTP));  // Wait for stop
    return 0;
}

/*
void Receive(void){
   UCB0CTL1 &= ~UCTR ;                  // Clear UCTR
   while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
    UCB0CTL1 |= UCTXSTT;                    // I2C start condition
    while (UCB0CTL1 & UCTXSTT);             // Start condition sent?
    UCB0CTL1 |= UCTXSTP;                    // I2C stop condition
    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts
}
*/