MSP432 and I2C configuration

Hi Tommaso,

I tried the BOOSTXL-EDUMKII LightSensor BoosterPack Example on the MSP432 + Educational BoosterPack MK II, and it worked fine without adding the delay. The lux value was shown on the LCD and changed according to the applied brightness. I found this example in CCS under TI Resource Explorer in MSPWare -> Development Tools -> MSP-EXP432P401R -> BoosterPack Examples. Perhaps you're using an older version of MSPWare? I'm using version 3_30_00_18.

Here's the example code for your reference.

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//****************************************************************************
//
// main.c - MSP-EXP432P401R + Educational Boosterpack MkII - Light Sensor
//
//          Displays lux value measured by the OPT3001 Digital Ambient
//          Light Sensor on the colored LCD. The MSP432 communicates
//          with the sensor through I2C.
//
//          The ambient light measurement is also used to automatically
//          adjust the LCD backlight.
//
//      *** Make sure J5 jumper on the BOOSTXL-EDUMKII is connected ***
//          to 3.LCD BACKLT
//
//****************************************************************************

#include "msp.h"
#include <driverlib.h>
#include <grlib.h>
#include <HAL_I2C.h>
#include <HAL_OPT3001.h>
#include "Crystalfontz128x128_ST7735.h"
#include "HAL_MSP_EXP432P401R_Crystalfontz128x128_ST7735.h"
#include <stdio.h>

/* Graphic library context */
Graphics_Context g_sContext;

/* Variable for storing lux value returned from OPT3001 */
float lux;

/* Timer_A Up Configuration Parameter */
const Timer_A_UpModeConfig upConfig =
{
        TIMER_A_CLOCKSOURCE_ACLK,               // ACLK Clock SOurce
        TIMER_A_CLOCKSOURCE_DIVIDER_1,          // ACLK/1 = 3MHz
        200,                                    // 200 tick period
        TIMER_A_TAIE_INTERRUPT_DISABLE,         // Disable Timer interrupt
        TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE,    // Disable CCR0 interrupt
        TIMER_A_DO_CLEAR                        // Clear value
};

/* Timer_A Compare Configuration Parameter  (PWM) */
Timer_A_CompareModeConfig compareConfig_PWM =
{
        TIMER_A_CAPTURECOMPARE_REGISTER_3,          // Use CCR3
        TIMER_A_CAPTURECOMPARE_INTERRUPT_DISABLE,   // Disable CCR interrupt
        TIMER_A_OUTPUTMODE_TOGGLE_SET,              // Toggle output but
        100                                         // 50% Duty Cycle
};

/*
 * Main function
 */
void main(void)
{
    /* Halting WDT and disabling master interrupts */
    MAP_WDT_A_holdTimer();
    MAP_Interrupt_disableMaster();

    /* Initializes Clock System */
    MAP_CS_setDCOCenteredFrequency(CS_DCO_FREQUENCY_48);
    MAP_CS_initClockSignal(CS_MCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1 );
    MAP_CS_initClockSignal(CS_HSMCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1 );
    MAP_CS_initClockSignal(CS_SMCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1 );
    MAP_CS_initClockSignal(CS_ACLK, CS_REFOCLK_SELECT, CS_CLOCK_DIVIDER_1);

    /* Initializes display */
    Crystalfontz128x128_Init();

    /* Set default screen orientation */
    Crystalfontz128x128_SetOrientation(0);

    /* Initializes graphics context */
    Graphics_initContext(&g_sContext, &g_sCrystalfontz128x128);
    Graphics_setForegroundColor(&g_sContext, GRAPHICS_COLOR_RED);
    Graphics_setBackgroundColor(&g_sContext, GRAPHICS_COLOR_WHITE);
    GrContextFontSet(&g_sContext, &g_sFontFixed6x8);
    Graphics_clearDisplay(&g_sContext);
    Graphics_drawStringCentered(&g_sContext,
                                    "Light Sensor:",
                                    AUTO_STRING_LENGTH,
                                    64,
                                    30,
                                    OPAQUE_TEXT);

    /* Configures P2.6 to PM_TA0.3 for using Timer PWM to control LCD backlight */
    MAP_GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P2, GPIO_PIN6,
            GPIO_PRIMARY_MODULE_FUNCTION);

    /* Configuring Timer_A0 for Up Mode and starting */
    MAP_Timer_A_configureUpMode(TIMER_A0_BASE, &upConfig);
    MAP_Timer_A_startCounter(TIMER_A0_BASE, TIMER_A_UP_MODE);

    /* Initialize compare registers to generate PWM */
    MAP_Timer_A_initCompare(TIMER_A0_BASE, &compareConfig_PWM);

    /* Initialize I2C communication */
    Init_I2C_GPIO();
    I2C_init();

    /* Initialize OPT3001 digital ambient light sensor */
    OPT3001_init();

    __delay_cycles(100000);

    while(1)
    {
        /* Obtain lux value from OPT3001 */
        lux = OPT3001_getLux();

        char string[20];
        sprintf(string, "%f", lux);
        Graphics_drawStringCentered(&g_sContext,
                                        (int8_t *)string,
                                        6,
                                        48,
                                        70,
                                        OPAQUE_TEXT);

        sprintf(string, "lux");
        Graphics_drawStringCentered(&g_sContext,
                                        (int8_t *)string,
                                        3,
                                        86,
                                        70,
                                        OPAQUE_TEXT);

        /* Adjust LCD Backlight */
        if (lux < 2000)
            compareConfig_PWM.compareValue = ((2000*0.1) + (lux*0.9))/2000 * 200;
        else
            compareConfig_PWM.compareValue = 200;
        Timer_A_initCompare(TIMER_A0_BASE, &compareConfig_PWM);
    }
}

Hope this helps.

Regards,

James

MSP Customer Applications

I'm using your configuration, hardware and software.