RIOT/cpu/cc430/cc430-adc.c

/* *************************************************************************************************
 *
 *  Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
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 *      its contributors may be used to endorse or promote products derived
 *      from this software without specific prior written permission.
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 *    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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/**
 * @ingroup cpu_cc430
 * @{
 */

/**
 * @file
 * @brief       eZ430 ADC driver
 *
 * @author      Oliver Hahm <oliver.hahm@inria.fr>
 *
 */


#include <legacymsp430.h>
#include "irq.h"
#include "cpu.h"
#include "cc430-adc.h"
#include "xtimer.h"

uint16_t adc12_result;
uint8_t  adc12_data_ready;

/************************************************************************************************
 * @fn          adc12_single_conversion
 * @brief       Init ADC12. Do single conversion. Turn off ADC12.
 * @param       none
 * @return      none
 ************************************************************************************************/
uint16_t adc12_single_conversion(uint16_t ref, uint16_t sht, uint16_t channel)
{
    /* Initialize the shared reference module  */
    REFCTL0 |= REFMSTR + ref + REFON;           /* Enable internal reference (1.5V or 2.5V) */

    /* Initialize ADC12_A  */
    ADC12CTL0 = sht + ADC12ON;                  /* Set sample time  */
    ADC12CTL1 = ADC12SHP;                       /* Enable sample timer */
    ADC12MCTL0 = ADC12SREF_1 + channel;         /* ADC input channel   */
    ADC12IE = 0x001;                            /* ADC_IFG upon conv result-ADCMEMO */
    irq_enable();

    /* Wait 66us to allow internal reference to settle */
    xtimer_usleep(66);

    /* Start ADC12 */
    ADC12CTL0 |= ADC12ENC;

    /* Clear data ready flag */
    adc12_data_ready = 0;

    /* Sampling and conversion start   */
    ADC12CTL0 |= ADC12SC;

    /* Wait until ADC12 has finished */
    xtimer_usleep(150);

    while (!adc12_data_ready);

    /* Shut down ADC12 */
    ADC12CTL0 &= ~(ADC12ENC | ADC12SC | sht);
    ADC12CTL0 &= ~ADC12ON;

    /* Shut down reference voltage   */
    REFCTL0 &= ~(REFMSTR + ref + REFON);

    ADC12IE = 0;

    /* Return ADC result */
    return adc12_result;
}

/*************************************************************************************************
 * @fn          ADC12ISR
 * @brief       Store ADC12 conversion result. Set flag to indicate data ready.
 * @param       none
 * @return      none
 *************************************************************************************************/
interrupt(ADC12_VECTOR) __attribute__((naked)) adc_isr(void)
{
    __enter_isr();

    switch(ADC12IV) {
        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 */
            adc12_result = ADC12MEM0;                       /* Move results, IFG is cleared */
            adc12_data_ready = 1;
            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;
    }

    __exit_isr();
}