TIVA C TM4C123G Launchpad Multiple ADC configure

uint32_t pui32ADC0Value[2];
int main(void)
{
	SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
    GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_3|GPIO_PIN_2);
    ADCSequenceDisable(ADC0_BASE, 0);
    ADCSequenceConfigure(ADC0_BASE, 0, ADC_TRIGGER_PROCESSOR, 0);
    ADCSequenceStepConfigure(ADC0_BASE, 0, 0, ADC_CTL_CH0);
    ADCSequenceStepConfigure(ADC0_BASE,0, 1, ADC_CTL_CH1 | ADC_CTL_IE |
                             ADC_CTL_END);
    ADCSequenceEnable(ADC0_BASE, 0);
    while(1)
    {
    	ADCIntClear(ADC0_BASE, 0);
        ADCProcessorTrigger(ADC0_BASE, 0);
        while(!ADCIntStatus(ADC0_BASE, 0, false))
        {
        }
        ADCSequenceDataGet(ADC0_BASE, 0, pui32ADC0Value);
    }
}

Hii Luis

As per your instruction, i have changed the code. I am using sequencer 0 for both adc inputs. but still getting same output in both the channels even if one is not even fed with input. kindly see the attached code.

I missed this before,
When using sequencer 0 you have use a table of size 8 even if you are just using 2 samples. So pui32ADC0Value should have size 8 instead of 2.

Now, how are you reading the data? How do you see it?
You know that pui32ADC0Value[0] should hold the data for CH0 and pui32ADC0Value[1] the data for CH1, correct?

Try to, instead of having a infinite loop of values, do just 1 reading.

Also, don't leave any input floating, have CH0 connected to GND and CH1 to 3.3V (with a resistor) for example. This is just to know exactly the values that the channels should be reading

Amit Ashara said:

The pui32ADC0Value can have the number of entry as many as there are conversions and not the number of steps. The API reads as long as the FIFO has data.

// This array is used for storing the data read from the ADC FIFO. It
// must be as large as the FIFO for the sequencer in use. This example
// uses sequence 3 which has a FIFO depth of 1. If another sequence
// was used with a deeper FIFO, then the array size must be changed.


In the Tivaware peripheral driver user guide does indeed say: "The number of samples available in the hardware FIFO are copied into the buffer, which is assumed to be large enough to hold that many samples"


Thank you for the correction Amit