Function rt_hw_adc_unit_init

bsp/efm32/drv_adc.c:732–793

/ * @brief * Initialize the specified ADC unit * * @details * * @note * * @param[in] device * Pointer to device descriptor * * @param[in] unitNumber * Unit number * * @return * Pointer to ADC device ******************************************************************************/

 *  Pointer to ADC device
 ******************************************************************************/
static struct efm32_adc_device_t *rt_hw_adc_unit_init(
    rt_device_t device,
    rt_uint8_t  unitNumber)
{
    struct efm32_adc_device_t       *adc;
    CMU_Clock_TypeDef               adcClock;
    ADC_Init_TypeDef                init = ADC_INIT_DEFAULT;

    do
    {
        /* Allocate device and set default value */
        adc = rt_malloc(sizeof(struct efm32_adc_device_t));
        if (adc == RT_NULL)
        {
            adc_debug("no memory for ADC%d driver\n", unitNumber);
            break;
        }
        adc->mode               = 0;
        adc->singleCount        = 0;
        adc->singleDmaChannel   = (rt_uint8_t)EFM32_NO_DMA;
        adc->scanCount          = 0;
        adc->scanDmaChannel     = (rt_uint8_t)EFM32_NO_DMA;

        /* Initialization */
        if (unitNumber >= ADC_COUNT)
        {
            break;
        }
        switch (unitNumber)
        {
        case 0:
            adc->adc_device     = ADC0;
            adcClock            = (CMU_Clock_TypeDef)cmuClock_ADC0;
            break;

        default:
            break;
        }

        /* Enable ADC clock */
        CMU_ClockEnable(adcClock, true);

        /* Reset */
        ADC_Reset(adc->adc_device);

        /* Configure ADC */
        // TODO: Fixed oversampling rate?
        init.ovsRateSel         = adcOvsRateSel4096;
        init.timebase           = ADC_TimebaseCalc(0);
        init.prescale           = ADC_PrescaleCalc(ADC_CONVERT_FREQUENCY, 0);
        ADC_Init(adc->adc_device, &init);

        return adc;
    } while(0);

    if (adc)
    {
        rt_free(adc);