MSPM0L1306: ADC12_0 values not consistence

Hi, Seema

That a long data table~

After you start ADC conversion, you need to wait for ADC conversion done.

In your code, you didn't wait and read adc result mem immediately.

Check this code example in SDK, will help you how to handle ADC mem read sequence.

C:\ti\mspm0_sdk_2_00_00_03\examples\nortos\LP_MSPM0L1306\driverlib\adc12_single_conversion

Regards,

Helic

Hi Helic,

Thank you for the reply but I already done that by using 10 mSec counter  and then start taking ADC conversion.
I already gone through the code which you have mention and getting these value variation. Expecting expert reply from your side as I think there is something which I am missing to do and due to which I am getting this fluctuation in ADC values. 

The answer I am getting from your side is very basic and logical things which I already tried and after my query not getting resolved I came here on forum.

I have checked number of similar questions on forum too but I have not get any answer. So expecting your expert answer.

Thank you in advance.

Hi, Seema

Please check this part firstly:

Helic Chi said:

After you start ADC conversion, you need to wait for ADC conversion done.

In your code, you didn't wait and read adc result mem immediately.

In the demo code, MCU need to wait for ADC result ready by running [while (false == gCheckADC);], when result is done, gCheckADC = true in ADC interrupt, and MCU can read ADC result from ADC result MEM.

int main(void)
{
    SYSCFG_DL_init();

    NVIC_EnableIRQ(ADC12_0_INST_INT_IRQN);
    gCheckADC = false;

    while (1) {
        DL_ADC12_startConversion(ADC12_0_INST);

        while (false == gCheckADC) {
            __WFE();
        }

        gAdcResult = DL_ADC12_getMemResult(ADC12_0_INST, DL_ADC12_MEM_IDX_0);

        if (gAdcResult > 0x7ff) {
            DL_GPIO_clearPins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);
        } else {
            DL_GPIO_setPins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);
        }
        gCheckADC = false;
        DL_ADC12_enableConversions(ADC12_0_INST);
    }
}

void ADC12_0_INST_IRQHandler(void)
{
    switch (DL_ADC12_getPendingInterrupt(ADC12_0_INST)) {
        case DL_ADC12_IIDX_MEM0_RESULT_LOADED:
            gCheckADC = true;
            break;
        default:
            break;
    }
}

For your code shown below, you didn't jam the CPU after ADC start. The CPU reads the results directly after the ADC is turned on, which will result in reading unknown results.

Please add more functions based on the SDK demo.

Regards,

Helic