usci_b_i2c_ex3_masterTxSingle.c

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 * Copyright (c) 2017, Texas Instruments Incorporated
 * All rights reserved.
 *
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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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 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 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
 
uint8_t transmitData;
 
void main (void)
{
    //Stop WDT
    WDT_A_hold(WDT_A_BASE);
 
    //Assign I2C pins to USCI_B0
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P3,
        GPIO_PIN1 + GPIO_PIN2
        );
 
    //Initialize transmit data packet
    transmitData = 0x01;
 
    //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 in 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);
 
    //Enable TX 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
        );
 
    while (1)
    {
        //Send single byte data.
        USCI_B_I2C_masterSendSingleByte(USCI_B0_BASE,
            transmitData
            );
 
        //Delay until transmission completes
        while (USCI_B_I2C_isBusBusy(USCI_B0_BASE)) ;
 
        //Delay between each transaction
        __delay_cycles(50);
 
        //Increment transmit data counter
        transmitData++;
    }
}
 
//******************************************************************************
//
//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)){
        //Vector 12: Transmit buffer empty - TXIF
        case USCI_I2C_UCTXIFG:
        {
            __no_operation();
            break;
        }
        default:  break;
    }
}