eusci_b_i2c_ex3_masterTxMultiple.c

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#include "driverlib.h"
 
//******************************************************************************
//
 
//******************************************************************************
//*****************************************************************************
//
//Set the address for slave module. This is a 7-bit address sent in the
//following format:
//[A6:A5:A4:A3:A2:A1:A0:RS]
//
//A zero in the "RS" position of the first byte means that the master
//transmits (sends) data to the selected slave, and a one in this position
//means that the master receives data from the slave.
//
//*****************************************************************************
#define SLAVE_ADDRESS 0x48
 
uint8_t TXData =0;                    // Pointer to TX data
uint8_t TXByteCtr;
 
void main(void)
{
    WDT_A_hold(WDT_A_BASE);
 
    //Set DCO frequency to 1MHz
    CS_setDCOFreq(CS_DCORSEL_0,CS_DCOFSEL_0);
    //Set ACLK = VLO with frequency divider of 1
    CS_initClockSignal(CS_ACLK,CS_VLOCLK_SELECT,CS_CLOCK_DIVIDER_1);
    //Set SMCLK = DCO with frequency divider of 1
    CS_initClockSignal(CS_SMCLK,CS_DCOCLK_SELECT,CS_CLOCK_DIVIDER_1);
    //Set MCLK = DCO with frequency divider of 1
    CS_initClockSignal(CS_MCLK,CS_DCOCLK_SELECT,CS_CLOCK_DIVIDER_1);
 
    // Configure Pins for I2C
    //Set P1.6 and P1.7 as Secondary Module Function Input.
    /*
 
    * Select Port 1
    * Set Pin 6, 7 to input Secondary Module Function, (UCB0SIMO/UCB0SDA, UCB0SOMI/UCB0SCL).
    */
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P1,
        GPIO_PIN6 + GPIO_PIN7,
        GPIO_SECONDARY_MODULE_FUNCTION
    );
 
    /*
     * Disable the GPIO power-on default high-impedance mode to activate
     * previously configured port settings
     */
    PMM_unlockLPM5();
 
    EUSCI_B_I2C_initMasterParam param = {0};
    param.selectClockSource = EUSCI_B_I2C_CLOCKSOURCE_SMCLK;
    param.i2cClk = CS_getSMCLK();
    param.dataRate = EUSCI_B_I2C_SET_DATA_RATE_400KBPS;
    param.byteCounterThreshold = 0;
    param.autoSTOPGeneration = EUSCI_B_I2C_NO_AUTO_STOP;
    EUSCI_B_I2C_initMaster(EUSCI_B0_BASE, &param);
 
    //Specify slave address
    EUSCI_B_I2C_setSlaveAddress(EUSCI_B0_BASE,
                SLAVE_ADDRESS
                );
 
    //Set Master in receive mode
    EUSCI_B_I2C_setMode(EUSCI_B0_BASE,
                EUSCI_B_I2C_TRANSMIT_MODE
                );
 
    //Enable I2C Module to start operations
    EUSCI_B_I2C_enable(EUSCI_B0_BASE);
 
    EUSCI_B_I2C_clearInterrupt(EUSCI_B0_BASE,
                EUSCI_B_I2C_TRANSMIT_INTERRUPT0 +
                EUSCI_B_I2C_NAK_INTERRUPT
                );
 
    //Enable master Receive interrupt
    EUSCI_B_I2C_enableInterrupt(EUSCI_B0_BASE,
                EUSCI_B_I2C_TRANSMIT_INTERRUPT0 +
                EUSCI_B_I2C_NAK_INTERRUPT
              );
    while(1)
    {
    __delay_cycles(1000);                   // Delay between transmissions
    TXByteCtr = 4;                          // Load TX byte counter
    TXData = 0;
 
    while (EUSCI_B_I2C_SENDING_STOP == EUSCI_B_I2C_masterIsStopSent
            (EUSCI_B0_BASE));
 
    EUSCI_B_I2C_masterSendMultiByteStart(EUSCI_B0_BASE,
            TXData++);
 
    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts
                                            // Remain in LPM0 until all data
                                            // is TX'd
                                            // Increment data byte
    }
}
 
//------------------------------------------------------------------------------
// The USCIAB0TX_ISR is structured such that it can be used to transmit any
// number of bytes by pre-loading TXByteCtr with the byte count. Also, TXData
// points to the next byte to transmit.
//------------------------------------------------------------------------------
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_B0_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_B0_VECTOR)))
#endif
void USCIB0_ISR(void)
{
    switch(__even_in_range(UCB0IV, USCI_I2C_UCBIT9IFG))
  {
        case USCI_NONE:             // No interrupts break;
            break;
        case USCI_I2C_UCALIFG:      // Arbitration lost
            break;
        case USCI_I2C_UCNACKIFG:    // NAK received (master only)
            //resend start if NACK
            EUSCI_B_I2C_masterSendStart(EUSCI_B0_BASE);
            break;
        case USCI_I2C_UCTXIFG0:     // TXIFG0
            // Check TX byte counter
            if (TXByteCtr)
            {
                EUSCI_B_I2C_masterSendMultiByteNext(EUSCI_B0_BASE, TXData++);
                // Decrement TX byte counter
                TXByteCtr--;
            }
            else
            {
                EUSCI_B_I2C_masterSendMultiByteStop(EUSCI_B0_BASE);
                // Exit LPM0
                __bic_SR_register_on_exit(CPUOFF);
            }
            break;
        default:
            break;
  }
}