TM4C123: Trouble in implementing ADC function

Hello, I am Sky.

I am struggling with implementing an ADC function on TM4C123.

I would like to make an ADC function which satisfies four conditions:

1) acquire two channels of ADC signals from ADC0_BASE, ADC1_BASE concurrently

2) synchronize with specific sampling rate (e.g., 200khz) using TIMER (not PWM)

3) use oversampling (4x) mode and calculate average values of them

4) use differential mode

Fortunately, I found well-defined two documents as below:

Ref 1. ADC Oversampling Techniques for Stellaris® Family Microcontrollers

(http://www.ti.com/lit/an/spma001a/spma001a.pdf)

Ref 2. C:\ti\TivaWare_C_Series-2.1.3.156\examples\peripherals\adc\differential.c

They gives me information on oversampling(4x), average values, and differential mode well.

However, I faced with a few questions,

Q1) My program hangs on ADCIntStatus command.

When I write the code on Ref 2,

it hangs on a line "while(!ADCIntStatus(ADC0_BASE, 3, false))".

I don't know how to fix it.

Q2) How can I manipulate sampling time of ADC using Timer?

In order to synchronize with Timer0 (not PWM), I used this command.

ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_TIMER, 0);

(When I refer to another manual which named "TivaWare™ Peripheral Driver Library", it explains that

"ADC_TRIGGER_TIMER - A trigger generated by a timer; configured with TimerControlTrigger().")

And then, I follow an example of 5 page of (Ref 1).

However, it seems that defined sampling rate of the Timer doesn't work.

How can I run ADC conversion with desired sampling rate which is defined by Timer?

For better understanding of my problem, I would like to attach my source code below:

=====================================================================

    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

    uint32_t sequence_number = 3;

    GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_3 | GPIO_PIN_2);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_ADC0))
    {
    }
    SysCtlDelay(10);

    ADCIntEnable(ADC0_BASE, sequence_number);
    ADCSequenceDisable(ADC0_BASE, sequence_number);

    ADCSequenceConfigure(ADC0_BASE, sequence_number, ADC_TRIGGER_TIMER, 0);
    ADCSoftwareOversampleConfigure(ADC0_BASE, sequence_number, 4);
    ADCSoftwareOversampleStepConfigure(ADC0_BASE, sequence_number, 0, (ADC_CTL_CH1 | ADC_CTL_IE | ADC_CTL_END));
    ADCSequenceEnable(ADC0_BASE, sequence_number);
    ADCIntEnable(ADC0_BASE, sequence_number);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_TIMER0))
    {
    }
    SysCtlDelay(10);
    TimerConfigure(TIMER0_BASE, TIMER_CFG_B_PERIODIC);
    TimerControlTrigger(TIMER0_BASE, TIMER_A, true);
    TimerLoadSet(TIMER0_BASE, TIMER_A, SysCtlClockGet() / 1000);
    TimerEnable(TIMER0_BASE, TIMER_A);

    while(1)
    {
        ADCProcessorTrigger(ADC0_BASE, sequence_number);
        while(!ADCIntStatus(ADC0_BASE, sequence_number, false))
        {
	}
	uint32_t g_ulAverage;
	ADCSoftwareOversampleDataGet(ADC0_BASE, sequence_number, &g_ulAverage, 4);

	GPIO_toggle(Board_LED0);
    }

=====================================================================

Please give me a solution.

Thanks in advance.

-Sky

+ Nov 16, 2016

As Amit Ashara suggested, I will update my posting after remove ADCProcessorTrigger command.