adc12_a_ex8_tempSensor.c

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/* --COPYRIGHT--,BSD
 * 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"
 
//******************************************************************************
//******************************************************************************
 
long temp;
volatile long IntDegF;
volatile long IntDegC;
 
void main (void)
{
    //Stop Watchdog Timer
    WDT_A_hold(WDT_A_BASE);
 
    //Initialize the ADC12_A Module
    /*
     * Base Address of ADC12_A Module
     * Use internal ADC12_A bit as sample/hold signal to start conversion
     * USE MODOSC 5MHZ Digital Oscillator as clock source
     * Use default clock divider of 1
     */
    ADC12_A_init(ADC12_A_BASE,
        ADC12_A_SAMPLEHOLDSOURCE_SC,
        ADC12_A_CLOCKSOURCE_ADC12OSC,
        ADC12_A_CLOCKDIVIDER_1);
 
    ADC12_A_enable(ADC12_A_BASE);
 
        ADC12_A_enable(ADC12_A_BASE);
 
    /*
     * Base Address of ADC12_A Module
     * For memory buffers 0-7 sample/hold for 768 clock cycles
     * For memory buffers 8-15 sample/hold for 4 clock cycles (default)
     * Disable Multiple Sampling
     *
     * Note: ADC12_A may have a minimum sample rate of 30us or 100us.
     * This example uses a sample time of ~154us to ensure it works.
     * 256 cycles (51.2us) or 512 cycles (100.4us) may be used, but
     * resulting readings may be less accurate.
     */
    ADC12_A_setupSamplingTimer(ADC12_A_BASE,
        ADC12_A_CYCLEHOLD_768_CYCLES,
        ADC12_A_CYCLEHOLD_4_CYCLES,
        ADC12_A_MULTIPLESAMPLESDISABLE);
 
    //Configure Memory Buffer
    /*
     * Base Addres of ADC12_A Module
     * Configure memory buffer 0
     * Map temp sensor to memory buffer 0
     * Vref+ = Vref+ (int)
     * Vref- = AVss
     * Memory buffer 0 is not the end of a sequence
     */
    ADC12_A_configureMemoryParam param = {0};
    param.memoryBufferControlIndex = ADC12_A_MEMORY_0;
    param.inputSourceSelect = ADC12_A_INPUT_TEMPSENSOR;
    param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_INT;
    param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
    param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;
    ADC12_A_configureMemory(ADC12_A_BASE ,&param);
 
    //Enable memory buffer 0 interrupt
    ADC12_A_clearInterrupt(ADC12_A_BASE,
        ADC12IFG0);
    ADC12_A_enableInterrupt(ADC12_A_BASE,
        ADC12IE0);
 
    //Configure internal reference
    //If ref generator busy, WAIT
    while ( REF_ACTIVE == Ref_isRefGenBusy(REF_BASE) ) ;
    //Select internal ref = 1.5V
    Ref_setReferenceVoltage(REF_BASE,
        REF_VREF1_5V);
    //Internal Reference ON
    Ref_enableReferenceVoltage(REF_BASE);
 
    //Delay (~75us) for Ref to settle
    __delay_cycles(75);
 
    while (1)
    {
        //Enable/Start first sampling and conversion cycle
        /*
         * Base address of ADC12_A Module
         * Start the conversion into memory buffer 0
         * Use the repeated sequence of channels
         */
        ADC12_A_startConversion(ADC12_A_BASE,
            ADC12_A_MEMORY_0,
            ADC12_A_SEQOFCHANNELS);
 
        //LPM4 with interrupts enabled
        __bis_SR_register(LPM4_bits + GIE);
        __no_operation();
 
        //Temperature in Celsius
        //((A10/4096*1500mV) - 680mV)*(1/2.25mV) = (A10/4096*667) - 302
        //= (A10 - 1855) * (667 / 4096)
        IntDegC = ((temp - 1855) * 667) / 4096;
 
        //Temperature in Fahrenheit
        //((A10/4096*1500mV) - 640mV)*(1/1.25mV) = (A10/4096*1200) - 512
        //= (A10 - 1748) * (1200 / 4096)
        IntDegF = ((temp - 1748) * 1200) / 4096;
 
        //SET BREAKPOINT HERE and watch IntDegC and IntDegF
        __no_operation();
    }
}
 
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC12_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(ADC12_VECTOR)))
#endif
void ADC12ISR (void)
{
    switch (__even_in_range(ADC12IV,34)){
        case  0: break;   //Vector  0:  No interrupt
        case  2: break;   //Vector  2:  ADC overflow
        case  4: break;   //Vector  4:  ADC timing overflow
        case  6:          //Vector  6:  ADC12IFG0
            //Move results, IFG is cleared
            temp = ADC12_A_getResults(ADC12_A_BASE,
            ADC12_A_MEMORY_0);
 
            //Exit active CPU
            __bic_SR_register_on_exit(LPM4_bits);
            break;
        case  8: break;   //Vector  8:  ADC12IFG1
        case 10: break;   //Vector 10:  ADC12IFG2
        case 12: break;   //Vector 12:  ADC12IFG3
        case 14: break;   //Vector 14:  ADC12IFG4
        case 16: break;   //Vector 16:  ADC12IFG5
        case 18: break;   //Vector 18:  ADC12IFG6
        case 20: break;   //Vector 20:  ADC12IFG7
        case 22: break;   //Vector 22:  ADC12IFG8
        case 24: break;   //Vector 24:  ADC12IFG9
        case 26: break;   //Vector 26:  ADC12IFG10
        case 28: break;   //Vector 28:  ADC12IFG11
        case 30: break;   //Vector 30:  ADC12IFG12
        case 32: break;   //Vector 32:  ADC12IFG13
        case 34: break;   //Vector 34:  ADC12IFG14
        default: break;
    }
}