CC1352R: Can't read AD Values, always some sort of fixed value with little noise

Part Number: CC1352R

Hy,

I am not able to read any analog voltages over ADC with TI driver ADC.h. I started from scratch with project adcsinglechannel_CC1352R1_LAUNCHXL_tirtos_ccs from C:\ti\simplelink_cc13x2_26x2_sdk_3_10_01_11\examples\rtos\CC1352R1_LAUNCHXL\drivers\adcsinglechannel.

I have the following code now:

CC1352R1_LAUNCHXL.h

/* Analog Capable DIOs */
#define CC1352R1_LAUNCHXL_DIO23_ANALOG          IOID_24

CC1352R1_LAUNCHXL.c

/*
 *  =============================== ADC ===============================
 */
#include <ti/drivers/ADC.h>
#include <ti/drivers/adc/ADCCC26XX.h>

ADCCC26XX_Object adcCC26xxObjects[CC1352R1_LAUNCHXL_ADCCOUNT];

const ADCCC26XX_HWAttrs adcCC26xxHWAttrs[CC1352R1_LAUNCHXL_ADCCOUNT] = {
    {
        .adcDIO              = CC1352R1_LAUNCHXL_DIO23_ANALOG,
        .adcCompBInput       = ADC_COMPB_IN_AUXIO7,
        .refSource           = ADCCC26XX_FIXED_REFERENCE,
        .samplingDuration    = ADCCC26XX_SAMPLING_DURATION_2P7_US,
        .inputScalingEnabled = true,
        .triggerSource       = ADCCC26XX_TRIGGER_MANUAL,
        .returnAdjustedVal   = false
    },

adcsinglechannel.c

void *threadFxn1(void *arg0)
{
    uint16_t     i;
    ADC_Handle   adc;
    ADC_Params   params;
    int_fast16_t res;

    ADC_Params_init(&params);
    adc = ADC_open(Board_ADC0, &params);
    for (i = 0; i < ADC_SAMPLE_COUNT; i++) {
        res = ADC_convert(adc, &adcValue1[i]);

        if (res == ADC_STATUS_SUCCESS) {

            adcValue1MicroVolt[i] = ADC_convertRawToMicroVolts(adc, adcValue1[i]);
        }
    }
    ADC_close(adc);

    return (NULL);
}

When I run the program I set a break poin at res = AD_convert and set different voltages to the pin DIO_24 (1.75V 1.62V 1.52V 1.43V 1.27V)

But the AD converter reads 184 on the very first measurement, then 152-154, independent on the actual input voltage.

Whats happening here? Might it be a hardware defect? Do I Initialize the AD converter incorrect?

Whats the maximum voltage, the pin can survive? I understand, when I set .inputScalingEnabled it can measure up to 1.4785V. What if input is higher? Would it damage the pin?

Any help appreciated

Harald