adc_ex1_avccRef.c

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 * Copyright (c) 2017, Texas Instruments Incorporated
 * All rights reserved.
 *
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 *    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
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 *    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,
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//******************************************************************************
//******************************************************************************
#include "driverlib.h"
#include "Board.h"
 
void main (void)
{
    //Stop Watchdog Timer
    WDT_A_hold(WDT_A_BASE);
 
    //Set A7 as an input pin.
    //Set appropriate module function
    GPIO_setAsPeripheralModuleFunctionInputPin(
            GPIO_PORT_ADC7,
            GPIO_PIN_ADC7,
            GPIO_FUNCTION_ADC7);
 
    //Set LED1 as an output pin.
    GPIO_setAsOutputPin(
            GPIO_PORT_LED1,
            GPIO_PIN_LED1);
 
    //Set LED2 as an output pin.
    GPIO_setAsOutputPin(
            GPIO_PORT_LED2,
            GPIO_PIN_LED2);
 
    /*
     * Disable the GPIO power-on default high-impedance mode to activate
     * previously configured port settings
     */
    PMM_unlockLPM5();
 
    //Initialize the ADC Module
    /*
     * Base Address for the ADC Module
     * Use internal ADC bit as sample/hold signal to start conversion
     * USE MODOSC 5MHZ Digital Oscillator as clock source
     * Use default clock divider of 1
     */
    ADC_init(ADC_BASE,
        ADC_SAMPLEHOLDSOURCE_SC,
        ADC_CLOCKSOURCE_ADCOSC,
        ADC_CLOCKDIVIDER_1);
 
    ADC_enable(ADC_BASE);
 
    /*
     * Base Address for the ADC Module
     * Sample/hold for 16 clock cycles
     * Do not enable Multiple Sampling
     */
    ADC_setupSamplingTimer(ADC_BASE,
            ADC_CYCLEHOLD_16_CYCLES,
            ADC_MULTIPLESAMPLESDISABLE);
 
    //Configure Memory Buffer
    /*
     * Base Address for the ADC Module
     * Use input A7
     * Use positive reference of AVcc
     * Use negative reference of AVss
     */
    ADC_configureMemory(ADC_BASE,
            ADC_INPUT_A7,
            ADC_VREFPOS_AVCC,
            ADC_VREFNEG_AVSS);
 
    ADC_clearInterrupt(ADC_BASE,
            ADC_COMPLETED_INTERRUPT);
 
    //Enable Memory Buffer interrupt
    ADC_enableInterrupt(ADC_BASE,
            ADC_COMPLETED_INTERRUPT);
 
    for (;;)
    {
        //Delay between conversions
        __delay_cycles(5000);
 
        //Enable and Start the conversion
        //in Single-Channel, Single Conversion Mode
        ADC_startConversion(ADC_BASE,
                ADC_SINGLECHANNEL);
 
        //LPM0, ADC10_ISR will force exit
        __bis_SR_register(CPUOFF + GIE);
        //For debug only
        __no_operation();
 
 
    }
}
 
//ADC10 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(ADC_VECTOR)))
#endif
void ADC_ISR (void)
{
    switch (__even_in_range(ADCIV,12)){
        case  0: break; //No interrupt
        case  2: break; //conversion result overflow
        case  4: break; //conversion time overflow
        case  6: break; //ADC10HI
        case  8: break; //ADC10LO
        case 10: break; //ADC10IN
        case 12:        //ADC10IFG0
            //(Automatically clears ADC10IFG0 by reading memory buffer)
            if (ADC_getResults(ADC_BASE) < 0x1FF){
 
                //Turn LED1 off
                GPIO_setOutputLowOnPin(
                    GPIO_PORT_LED1,
                    GPIO_PIN_LED1
                );
 
                //Turn LED2 off
                GPIO_setOutputLowOnPin(
                    GPIO_PORT_LED2,
                    GPIO_PIN_LED2
                );
            }
            else {
                //Turn LED1 on
                GPIO_setOutputHighOnPin(
                    GPIO_PORT_LED1,
                    GPIO_PIN_LED1
                );
 
                //Turn LED2 on
                GPIO_setOutputHighOnPin(
                    GPIO_PORT_LED2,
                    GPIO_PIN_LED2
                );
            }
 
          //Clear CPUOFF bit from 0(SR)
            //Breakpoint here and watch ADC_Result
          __bic_SR_register_on_exit(CPUOFF);
          break;
        default: break;
    }
}