usci_b_i2c_ex2_masterTxMultiple.c

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 * Copyright (c) 2017, Texas Instruments Incorporated
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 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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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
//*****************************************************************************
//
//Specify number of bytes to be transmitted
//
//*****************************************************************************
#define TXLENGTH 0x04
 
uint8_t transmitData[40] = {  0x61,
                                    0x62,
                                    0x63,
                                    0x64,
                                    0x65,
                                    0x66,
                                    0x67,
                                    0x68};
 
uint8_t transmitCounter = 0;
 
void main ()
{
    //Stop WDT
    WDT_A_hold(WDT_A_BASE);
 
    //Assign I2C pins to USCI_B0
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P3,
        GPIO_PIN1 + GPIO_PIN2
        );
 
    //Initialize Master
    USCI_B_I2C_initMasterParam param = {0};
    param.selectClockSource = USCI_B_I2C_CLOCKSOURCE_SMCLK;
    param.i2cClk = UCS_getSMCLK();
    param.dataRate = USCI_B_I2C_SET_DATA_RATE_400KBPS;
    USCI_B_I2C_initMaster(USCI_B0_BASE, &param);
 
    //Specify slave address
    USCI_B_I2C_setSlaveAddress(USCI_B0_BASE,
        SLAVE_ADDRESS
        );
 
    //Set Transmit mode
    USCI_B_I2C_setMode(USCI_B0_BASE,
        USCI_B_I2C_TRANSMIT_MODE
        );
 
    //Enable I2C Module to start operations
    USCI_B_I2C_enable(USCI_B0_BASE);
 
 
    while (1)
    {
        //Enable transmit Interrupt
        USCI_B_I2C_clearInterrupt(USCI_B0_BASE,
            USCI_B_I2C_TRANSMIT_INTERRUPT
            );
        USCI_B_I2C_enableInterrupt(USCI_B0_BASE,
            USCI_B_I2C_TRANSMIT_INTERRUPT
            );
 
        //Delay between each transaction
        __delay_cycles(50);
 
        //Load TX byte counter
        transmitCounter = 1;
 
        //Initiate start and send first character
        USCI_B_I2C_masterSendMultiByteStart(USCI_B0_BASE,
            transmitData[0]
            );
 
        //Enter LPM0 with interrupts enabled
        __bis_SR_register(LPM0_bits + GIE);
        __no_operation();
 
        //Delay until transmission completes
        while (USCI_B_I2C_isBusBusy(USCI_B0_BASE)) ;
    }
}
 
//******************************************************************************
//
//This is the USCI_B0 interrupt vector service routine.
//
//******************************************************************************
#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 USCI_B0_ISR (void)
{
    switch (__even_in_range(UCB0IV,12)){
        case USCI_I2C_UCTXIFG:
        {
            //Check TX byte counter
            if (transmitCounter < TXLENGTH){
                //Initiate send of character from Master to Slave
                USCI_B_I2C_masterSendMultiByteNext(USCI_B0_BASE,
                    transmitData[transmitCounter]
                    );
 
                //Increment TX byte counter
                transmitCounter++;
            } else   {
                //Initiate stop only
                USCI_B_I2C_masterSendMultiByteStop(USCI_B0_BASE);
 
                //Clear master interrupt status
                USCI_B_I2C_clearInterrupt(USCI_B0_BASE,
                    USCI_B_I2C_TRANSMIT_INTERRUPT);
 
                //Exit LPM0 on interrupt return
                __bic_SR_register_on_exit(LPM0_bits);
            }
            break;
        }
    }
}