eusci_b_i2c_ex1_slaveRXMultiple.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--*/
/*******************************************************************************
 * MSP430i2xx EUSCI_B I2C - Slave receive multiple bytes
 *
 * Description: In this example, the device is configured as an I2C slave. It
 * receives bytes over I2C and stores them in an array for further inspect. The
 * device stays in LPM0 for the entire interaction. This example can be
 * modified to change the length of received bytes. Start this example
 * before running the corresponding master code.
 *
 *
 *                                /|\  /|\
 *                MSP430i2041     10k  10k      MSP430i2041
 *                   slave         |    |         master
 *             -----------------   |    |   -----------------
 *            |     P1.6/UCB0SCL|<-|----+->|P1.6/UCB0SCL     |
 *            |                 |  |       |                 |
 *            |                 |  |       |                 |
 *            |     P1.7/UCB0SDA|<-+------>|P1.7/UCB0SDA     |
 *            |                 |          |                 |
 *
 * Author: Zack Lalanne
 ******************************************************************************/
 
#include "driverlib.h"
 
#define SLAVE_ADDRESS       0x48
#define NUM_OF_RX_BYTES     4
 
static volatile uint8_t RXData[NUM_OF_RX_BYTES];
static volatile uint8_t RXDataIndex;
 
int main(void) {
 
    EUSCI_B_I2C_initSlaveParam i2cConfig = {
        SLAVE_ADDRESS,                              // Slave Address
        EUSCI_B_I2C_OWN_ADDRESS_OFFSET0,
        EUSCI_B_I2C_OWN_ADDRESS_ENABLE
    };
 
    WDT_hold(WDT_BASE);
 
    // Setting the DCO to use the internal resistor. DCO will be at 16.384MHz
    CS_setupDCO(CS_INTERNAL_RESISTOR);
 
 
    // Setting P1.6 and P1.7 as I2C pins
    GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,
                                               GPIO_PIN6 | GPIO_PIN7,
                                               GPIO_PRIMARY_MODULE_FUNCTION);
 
    // Setting up I2C communication as slave
    EUSCI_B_I2C_initSlave(EUSCI_B0_BASE, &i2cConfig);
 
    // Set slave in receive mode
    EUSCI_B_I2C_setMode(EUSCI_B0_BASE, EUSCI_B_I2C_RECEIVE_MODE);
 
    // Enable the module for operation
    EUSCI_B_I2C_enable(EUSCI_B0_BASE);
 
    // Enable needed I2C interrupts
    EUSCI_B_I2C_clearInterrupt(EUSCI_B0_BASE,
                                   EUSCI_B_I2C_RECEIVE_INTERRUPT0);
    EUSCI_B_I2C_enableInterrupt(EUSCI_B0_BASE,
                                EUSCI_B_I2C_RECEIVE_INTERRUPT0);
 
    // Go to sleep and wait for LPM exit
    __bis_SR_register(LPM0_bits | GIE);
}
 
#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: break;
        case USCI_I2C_UCALIFG: break;
        case USCI_I2C_UCNACKIFG:
        case USCI_I2C_UCSTTIFG: break;
        case USCI_I2C_UCSTPIFG: break;
        case USCI_I2C_UCRXIFG3: break;
        case USCI_I2C_UCTXIFG3: break;
        case USCI_I2C_UCRXIFG2: break;
        case USCI_I2C_UCTXIFG2: break;
        case USCI_I2C_UCRXIFG1: break;
        case USCI_I2C_UCTXIFG1: break;
        case USCI_I2C_UCRXIFG0:
            RXData[RXDataIndex++] = EUSCI_B_I2C_slaveGetData(EUSCI_B0_BASE);
 
            // Reset index if at end of array
            if(RXDataIndex == NUM_OF_RX_BYTES) {
                RXDataIndex = 0;
            }
 
            break;
        case USCI_I2C_UCTXIFG0: break;
        case USCI_I2C_UCBCNTIFG: break;
        case USCI_I2C_UCCLTOIFG: break;
        case USCI_I2C_UCBIT9IFG: break;
        default: break;
    }
}