usci_b_i2c_ex1_masterRxSingle.c

Go to the documentation of this file.

/* --COPYRIGHT--,BSD
 * Copyright (c) 2017, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    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"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * --/COPYRIGHT--*/
#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 receivedData;
 
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 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 Master in receive mode
    USCI_B_I2C_setMode(USCI_B0_BASE,
        USCI_B_I2C_RECEIVE_MODE
        );
 
    //Enable I2C Module to start operations
    USCI_B_I2C_enable(USCI_B0_BASE);
 
    //Enable master Receive interrupt
    USCI_B_I2C_clearInterrupt(USCI_B0_BASE,
        USCI_B_I2C_RECEIVE_INTERRUPT
        );
    USCI_B_I2C_enableInterrupt(USCI_B0_BASE,
        USCI_B_I2C_RECEIVE_INTERRUPT
        );
 
    while (1)
    {
        //Initiate command to receive a single character from Slave
        USCI_B_I2C_masterReceiveSingleStart(USCI_B0_BASE);
 
        //Enter low power mode 0 with interrupts enabled.
        //Wait until character is received.
        __bis_SR_register(LPM0_bits + GIE);
        __no_operation();
    }
}
 
//******************************************************************************
//
//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 10: Data received - RXIFG
        case USCI_I2C_UCRXIFG:
        {
            //Grab data from data register
            receivedData = USCI_B_I2C_masterReceiveSingle(
                USCI_B0_BASE);
 
            //Exit low power mode 0 and disable GIE on interrupt exit
            __bic_SR_register_on_exit(LPM0_bits + GIE);
 
            break;
        }
 
        default:    break;
    }
}