comp_b_ex5_TAx.c

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 * Copyright (c) 2017, Texas Instruments Incorporated
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 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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//******************************************************************************
//******************************************************************************
 
#include "driverlib.h"
 
#define TIMER_A_PERIOD 0xFFFF
#define UCS_MCLK_DESIRED_FREQUENCY_IN_KHZ 12000
#define UCS_MCLK_FLLREF_RATIO 374
 
Timer_A_initUpModeParam initUpModeParam = {0};
 
void main (void)
{
    //Stop WDT
    WDT_A_hold(WDT_A_BASE);
 
    //Set DCO FLL reference = REFO
    UCS_initClockSignal(
        UCS_FLLREF,
        UCS_REFOCLK_SELECT,
        UCS_CLOCK_DIVIDER_1
        );
 
    //Set ACLK = REFO
    UCS_initClockSignal(
        UCS_ACLK,
        UCS_REFOCLK_SELECT,
        UCS_CLOCK_DIVIDER_1
        );
 
    //Set Ratio and Desired MCLK Frequency  and init DCO
    UCS_initFLLSettle(
        UCS_MCLK_DESIRED_FREQUENCY_IN_KHZ,
        UCS_MCLK_FLLREF_RATIO
        );
 
 
    //Initialize the Comparator B module
    /*
     * Base Address of Comparator B,
     * Pin CB0 to Positive(+) Terminal,
     * Reference Voltage to Negative(-) Terminal,
     * Normal Power Mode,
     * Output Filter On with minimal delay,
     * Non-Inverted Output Polarity
     */
    Comp_B_initParam initParam = {0};
    initParam.positiveTerminalInput = COMP_B_INPUT0;
    initParam.negativeTerminalInput = COMP_B_VREF;
    initParam.powerModeSelect = COMP_B_POWERMODE_NORMALMODE;
    initParam.outputFilterEnableAndDelayLevel = COMP_B_FILTEROUTPUT_DLYLVL1;
    initParam.invertedOutputPolarity = COMP_B_NORMALOUTPUTPOLARITY;
    Comp_B_init(COMP_B_BASE, &initParam);
 
    //Set the reference voltage that is being supplied to the (-) terminal
    /*
     * Base Address of Comparator B,
     * Reference Voltage of 2.0 V,
     * Lower Limit of Vcc*(8/32) = (1/4)*Vcc,
     * Upper Limit of Vcc*(24/32) = (3/4)*Vcc
     * Static Mode Accuracy
     */
    Comp_B_configureReferenceVoltageParam refVoltageParam = {0};
    refVoltageParam.supplyVoltageReferenceBase = COMP_B_VREFBASE_VCC;
    refVoltageParam.lowerLimitSupplyVoltageFractionOf32 = 8;
    refVoltageParam.upperLimitSupplyVoltageFractionOf32 = 24;
    refVoltageParam.referenceAccuracy = COMP_B_ACCURACY_STATIC;
    Comp_B_configureReferenceVoltage(COMP_B_BASE, &refVoltageParam);
 
    //Allow power to Comparator module
    Comp_B_enable(COMP_B_BASE);
 
    //delay for the reference to settle
    __delay_cycles(75);
 
    //Start timer TIMER_A0 in up mode
    initUpModeParam.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;
    initUpModeParam.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_1;
    initUpModeParam.timerPeriod = TIMER_A_PERIOD;
    initUpModeParam.timerInterruptEnable_TAIE = TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;
    initUpModeParam.captureCompareInterruptEnable_CCR0_CCIE =
        TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;
    initUpModeParam.timerClear = TIMER_A_DO_CLEAR;
    initUpModeParam.startTimer = true;
    Timer_A_initUpMode(TIMER_A0_BASE, &initUpModeParam);
 
    //Start timer TIMER_A1 in up mode
    initUpModeParam.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;
    initUpModeParam.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_1;
    initUpModeParam.timerPeriod = TIMER_A_PERIOD;
    initUpModeParam.timerInterruptEnable_TAIE = TIMER_A_TAIE_INTERRUPT_DISABLE;
    initUpModeParam.captureCompareInterruptEnable_CCR0_CCIE =
        TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;
    initUpModeParam.timerClear = TIMER_A_DO_CLEAR;
    initUpModeParam.startTimer = true;
    Timer_A_initUpMode(TIMER_A1_BASE, &initUpModeParam);
    
    //Capture Falling Edge
    Timer_A_initCaptureModeParam initCaptureMode = {0};
    initCaptureMode.captureRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;
    initCaptureMode.captureMode = TIMER_A_CAPTUREMODE_FALLING_EDGE;
    initCaptureMode.captureInputSelect = TIMER_A_CAPTURE_INPUTSELECT_CCIxB;
    initCaptureMode.synchronizeCaptureSource = TIMER_A_CAPTURE_SYNCHRONOUS;
    initCaptureMode.captureInterruptEnable = TIMER_A_CAPTURECOMPARE_INTERRUPT_DISABLE;
    initCaptureMode.captureOutputMode = TIMER_A_OUTPUTMODE_OUTBITVALUE;
    Timer_A_initCaptureMode(TIMER_A0_BASE, &initCaptureMode);
    
    //Capture Rising Edge, Enable Interrupt
    Timer_A_clearCaptureCompareInterrupt(TIMER_A1_BASE,
        TIMER_A_CAPTURECOMPARE_REGISTER_1);
        
    initCaptureMode.captureRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;
    initCaptureMode.captureMode = TIMER_A_CAPTUREMODE_RISING_EDGE;
    initCaptureMode.captureInputSelect = TIMER_A_CAPTURE_INPUTSELECT_CCIxB;
    initCaptureMode.synchronizeCaptureSource = TIMER_A_CAPTURE_SYNCHRONOUS;
    initCaptureMode.captureInterruptEnable = TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE;
    initCaptureMode.captureOutputMode = TIMER_A_OUTPUTMODE_OUTBITVALUE;
    Timer_A_initCaptureMode(TIMER_A1_BASE, &initCaptureMode);
    
    //Set P1.0 to output direction
    GPIO_setAsOutputPin(
        GPIO_PORT_P1,
        GPIO_PIN0
        );
 
    //Enter LPM0 with global interrupts enabled
    __bis_SR_register(LPM3_bits + GIE);
 
    //For Debug
    __no_operation();
}
 
//******************************************************************************
//
//This is the TIMER1_A1_VECTOR interrupt vector service routine.
//
//******************************************************************************
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=TIMER1_A1_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(TIMER1_A1_VECTOR)))
#endif
void TIMER_A (void)
{
    uint16_t temp;
 
    switch ( TA1IV){
        case  2:
 
            //Re-Start timer TIMER_A0
            initUpModeParam.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;
            initUpModeParam.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_1;
            initUpModeParam.timerPeriod = TIMER_A_PERIOD;
            initUpModeParam.timerInterruptEnable_TAIE = TIMER_A_TAIE_INTERRUPT_DISABLE;
            initUpModeParam.captureCompareInterruptEnable_CCR0_CCIE =
                TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;
            initUpModeParam.timerClear = TIMER_A_DO_CLEAR;
            initUpModeParam.startTimer = true;
            Timer_A_initUpMode(TIMER_A0_BASE, &initUpModeParam);
 
            //Re-Start timer TIMER_A1
            initUpModeParam.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;
            initUpModeParam.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_1;
            initUpModeParam.timerPeriod = TIMER_A_PERIOD;
            initUpModeParam.timerInterruptEnable_TAIE = TIMER_A_TAIE_INTERRUPT_DISABLE;
            initUpModeParam.captureCompareInterruptEnable_CCR0_CCIE =
                TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;
            initUpModeParam.timerClear = TIMER_A_DO_CLEAR;
            initUpModeParam.startTimer = true;
            Timer_A_initUpMode(TIMER_A1_BASE, &initUpModeParam);
 
 
            //Compare On and off time of input signal
            temp = (Timer_A_getCaptureCompareCount(TIMER_A1_BASE,
                        TIMER_A_CAPTURECOMPARE_REGISTER_1
                        )) >> 1;
 
            if (Timer_A_getCaptureCompareCount(TIMER_A0_BASE,
                    TIMER_A_CAPTURECOMPARE_REGISTER_1
                    ) > temp){
                //set P1.0
                GPIO_setOutputHighOnPin(
                    GPIO_PORT_P1,
                    GPIO_PIN0
                    );
            } else   {
                //Clear P1.0 LED off
                GPIO_setOutputLowOnPin(
                    GPIO_PORT_P1,
                    GPIO_PIN0
                    );
            }
            break;
        case  4: break;  //CCR2 not used
        case  6: break;  //CCR3 not used
        case  8: break;  //CCR4 not used
        case 10: break;  //CCR5 not used
        case 12: break;  //Reserved not used
        case 14:         //Overflow
            __no_operation();
 
            //If input frequency < 200Hz, trap here
            while (1) ;
        default: break;
    }
}