CCS/LDC1041EVM: Issue with MSP432

Sylvain,

   I have been able to discuss with my colleague but unfortunately the example he has is for the LDC2114.   Looking back on this and the prior thread, I believe the issue is with the chip select (CSB).  The four-wire mode provided by the MSP432 uses a concept of slave transmit enable (STE), which is not the same as a chip select.  I have attached a snippet on how you could write to the spi with chip select.

Chris

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/******************************************************************************
 * MSP432 SPI - 3-wire Master Incremented Data
 *
 * This example shows how SPI master talks to SPI slave using 3-wire mode.
 * Incrementing data is sent by the master starting at 0x01. Received data is
 * expected to be same as the previous transmission.  eUSCI RX ISR is used to
 * handle communication with the CPU, normally in LPM0. Because all execution 
 * after LPM0 is in ISRs, initialization waits for DCO to stabilize against 
 * ACLK.
 *
 * Note that in this example, EUSCIB0 is used for the SPI port. If the user
 * wants to use EUSCIA for SPI operation, they are able to with the same APIs
 * with the EUSCI_AX parameters.
 *
 * ACLK = ~32.768kHz, MCLK = SMCLK = DCO 3MHz
 *
 * Use with SPI Slave Data Echo code example.
 *
 *                MSP432P401
 *              -----------------
 *             |                 |
 *             |                 |
 *             |                 |
 *             |             P1.6|-> Data Out (UCB0SIMO)
 *             |                 |
 *             |             P1.7|<- Data In (UCB0SOMI)
 *             |                 |
 *             |             P1.5|-> Serial Clock Out (UCB0CLK)
 *******************************************************************************/
/* DriverLib Includes */
#include <ti/devices/msp432p4xx/driverlib/driverlib.h>

/* Standard Includes */
#include <stdint.h>
#include <stdbool.h>

uint8_t TXData[2];

//![Simple SPI Config]
/* SPI Master Configuration Parameter */
const eUSCI_SPI_MasterConfig spiMasterConfig =
{
        EUSCI_B_SPI_CLOCKSOURCE_SMCLK,             // SMCLK Clock Source
        3000000,                                   // SMCLK = DCO = 3MHZ
        500000,                                    // SPICLK = 500khz
        EUSCI_B_SPI_MSB_FIRST,                     // MSB First
        EUSCI_B_SPI_PHASE_DATA_CHANGED_ONFIRST_CAPTURED_ON_NEXT,    // Phase
        EUSCI_B_SPI_CLOCKPOLARITY_INACTIVITY_HIGH, // High polarity
        EUSCI_B_SPI_3PIN                           // 3Wire SPI Mode
};
//![Simple SPI Config]

int main(void)
{
    /* Halting WDT  */
    WDT_A_holdTimer();

    //![Simple SPI Example]
    /* Selecting P1.5 P1.6 and P1.7 in SPI mode */
    GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P1,
            GPIO_PIN5 | GPIO_PIN6 | GPIO_PIN7, GPIO_PRIMARY_MODULE_FUNCTION);

    /* Configuring SPI in 3wire master mode */
    SPI_initMaster(EUSCI_B0_BASE, &spiMasterConfig);

    /* Enable SPI module */
    SPI_enableModule(EUSCI_B0_BASE);

    TXData[0] = 0x01;
    TXData[1] = 0x02;

    /*
     * Send instruction with chip select
     */

    /* Polling to see if the TX buffer is ready */
    while (!(SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));

    /* Set Chip select here */

    /* Transmitting data to slave, the eUSCI is buffered so two writes can be made*/
    SPI_transmitData(EUSCI_B0_BASE, TXData[0]);
    SPI_transmitData(EUSCI_B0_BASE, TXData[1]);

    while (!(SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));
    SPI_clearInterruptFlag(EUSCI_B0_BASE,EUSCI_B_SPI_RECEIVE_INTERRUPT);
    
    /* do not clear the chip select until after the last byte is transmitted.  The
     * TX IFG indicates that the transmit buffer is free and can be loaded.  The
     * RX IFG indicates that the byte has been actually transmitted - actually 
     * in order to receive the transmit buffer needs to be loaded to generate clock
     * pulses.
     */
 
    while (!(SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_RECEIVE_INTERRUPT)));

    /* Clear Chip select here */

    /* Continue code */ 
}