TM4C1294NCPDT: Task blocks or gets stack overflow without apparent reason

Hi,

  I see you create a semaphore Adc_sem but I don't see it being used in your task. Normally, you would insert Semaphore_pend(Adc_sem) inside the while loop. It will block until it receives a Semaphore_post(Adc_sem) in the ISR. 

  Below is an example for TM4C123 using semaphore but the idea is the same. The LedToggle task is pending on Semaphore_pend(LEDSem, BIOS_WAIT_FOREVER) and hence is blocking until the timer generates an interrupt from which Semaphore_post(LEDSem) is issued to unblock the LedToggle task. 

//----------------------------------------
// BIOS header files
//----------------------------------------
#include <xdc/std.h>  						//mandatory - have to include first, for BIOS types
#include <ti/sysbios/BIOS.h> 				//mandatory - if you call APIs like BIOS_start()
#include <xdc/runtime/Log.h>				//needed for any Log_info() call
#include <xdc/cfg/global.h> 				//header file for statically defined objects/handles
#include <xdc/runtime/System.h>
#include <xdc/runtime/Error.h>
#include <ti/sysbios/hal/Hwi.h>
#include <ti/sysbios/knl/Task.h>
#include <ti/sysbios/knl/Semaphore.h>



//------------------------------------------
// TivaWare Header Files
//------------------------------------------
#include <stdint.h>
#include <stdbool.h>

#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "driverlib/timer.h"


//----------------------------------------
// Prototypes
//----------------------------------------
void hardware_init(void);
void ledToggle(void);
void Timer_ISR(void);


//---------------------------------------
// Globals
//---------------------------------------
volatile int16_t i16ToggleCount = 0;
Semaphore_Handle LEDSem;


//---------------------------------------------------------------------------
// main()
//---------------------------------------------------------------------------
void main(void)
{

    Task_Params TaskParams;
    Task_Handle LedToggleTask;
    Error_Block eb;
    /* Initialize error block and TaskParams to default values */
    Error_init(&eb);
    Task_Params_init(&TaskParams);
    TaskParams.stackSize = 2096;
    TaskParams.priority = 1;
    LedToggleTask = Task_create((Task_FuncPtr)ledToggle, &TaskParams, &eb);
    if (LedToggleTask == NULL) {
    System_abort("Task create failed");
    }

    /*
    * Create semaphore with initial count = 0 and default params
    */
    LEDSem = Semaphore_create(0, NULL, &eb);
    if (LEDSem == NULL) {
    System_abort("Semaphore create failed");
    }


   hardware_init();							// init hardware via Xware

   BIOS_start();

}


//---------------------------------------------------------------------------
// hardware_init()
//
// inits GPIO pins for toggling the LED
//---------------------------------------------------------------------------
void hardware_init(void)
{
	uint32_t ui32Period;

	//Set CPU Clock to 40MHz. 400MHz PLL/2 = 200 DIV 5 = 40MHz
	SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);

	// ADD Tiva-C GPIO setup - enables port, sets pins 1-3 (RGB) pins for output
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
	GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);

	// Turn on the LED
	GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3, 4);

	// Timer 2 setup code
	SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER2);			// enable Timer 2 periph clks
	TimerConfigure(TIMER2_BASE, TIMER_CFG_PERIODIC);		// cfg Timer 2 mode - periodic

	ui32Period = (SysCtlClockGet() /2);						// period = CPU clk div 2 (500ms)
	TimerLoadSet(TIMER2_BASE, TIMER_A, ui32Period);			// set Timer 2 period

	TimerIntEnable(TIMER2_BASE, TIMER_TIMA_TIMEOUT);		// enables Timer 2 to interrupt CPU

	TimerEnable(TIMER2_BASE, TIMER_A);						// enable Timer 2

}


//---------------------------------------------------------------------------
// ledToggle()
//
// toggles LED on Tiva-C LaunchPad
//---------------------------------------------------------------------------
void ledToggle(void)
{

	while(1)
	{
		Semaphore_pend(LEDSem, BIOS_WAIT_FOREVER);				// wait for Sem from ISR

		// LED values - 2=RED, 4=BLUE, 8=GREEN
		if(GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_2))
		{
			GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3, 0);
		}
		else
		{
			GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 4);
		}

		i16ToggleCount += 1;									// keep track of #toggles

		Log_info1("LED TOGGLED [%u] TIMES",i16ToggleCount);		// send toggle count to UIA

	}

}


//---------------------------------------------------------------------------
// Timer ISR - called by BIOS Hwi (see app.cfg)
//
// Posts Swi (or later a Semaphore) to toggle the LED
//---------------------------------------------------------------------------
void Timer_ISR(void)
{
    TimerIntClear(TIMER2_BASE, TIMER_TIMA_TIMEOUT);			// must clear timer flag FROM timer

	Semaphore_post(LEDSem);										// post LEDSwi
}

Here is a link to TI-RTOS training. https://training.ti.com/sites/default/files/docs/TI_RTOS_Kernel_Workshop_Student_Guide_rev4.00.pdf. Hope you will find it useful.

One more comment is that you seem to have an old XDCtools and TI-RTOS. The recommended TI-RTOS version is 2.16.00.08. You can download from http://downloads.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/tirtos/index.html. The recommended XDCtools that works with TI-RTOS version 2.16.00.08 is XDCtools version 3.32.00.06 which you can download from http://downloads.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/rtsc/3_32_00_06/index_FDS.html.